Tag: Diamondback moth

Predicted Diamondback Moth Development

After arriving in western Canada in the spring, migrant diamondback moths begin to reproduce. In western Canada, there are usually up to four non-migrant generations of diamondback moth produced in ‘local populations’ during the growing season.

Due to warm weather in 2023, development of diamondback moth populations is well ahead of average development. Model simulations to August 20, 2023, indicate that the fourth and fifth generations of non-migrant adults (based on early May arrival dates) are currently occurring across the Canadian prairies (Fig. 1). Fourth generation diamondback moths, if present, are occurring farther north on the prairies compared to fifth generation diamondback moths.

**Figure 1.  Predicted number of non-migrant generations of diamondback moth (*Plutella xylostella*) expected to have occurred across the Canadian prairies as of August 20, 2023.**

In a ‘normal year’ based on climate normals data (e.g., 30-year averages), we would expect the third generation of non-migrant diamondback moth to be occurring across the northern prairie region at this time of year, with the fourth generation occurring across the southern regions of the prairies (Fig. 2).

Figure 2. The predicted number of non-migrant generations of diamondback moth (*Plutella xylostella*) expected to have occurred across the Canadian prairies as of August 20, based on climate normals data.

Considering advanced canola development, risk across the southern and central regions of the prairies associated with the development of a fifth generation of diamondback moth should be minimal. In regions where broccoli, rutabaga, and other brassica vegetables are grown and where crops are late to mature, these crops could still be at risk of damage from diamondback moth. Keep scouting for diamondback moth where crops are still green and could provide a desirable food source for developing diamondback moth larvae.

To scout for diamondback moth, estimate the number of diamondback moth larvae per m² at several locations in a field. The economic threshold for diamondback moth is NOT based on pheromone traps or sweep net samples, but on the density of larvae per plant. For immature and flowering canola, the economic threshold is 100-150 larvae/m². In podded canola, the economic threshold is 200-300 larvae/m². See the Field Crop and Forage Pests guide and monitoring protocol for more information about scouting for diamondback moth.

2023 Week 15 (Released August 17, 2023)

Insect scouting season continues, even though harvest has already started in some regions! Development of many pest insects has been ahead of schedule all year in most parts of the prairies, thanks to warmer than average weather during this growing season.

Adult grasshoppers are now in flight and will be laying eggs across the prairie region. Scouting individual fields is the best way to estimate crop risk. At this time of year, we start to look forward to next season. Insect surveyors are working to estimate grasshopper populations in ditches/roadsides and may be collecting samples of adult grasshoppers for species identification.

Aside from grasshoppers, fall surveys for wheat midge and wheat stem sawfly will begin as harvest is completed in Alberta and Saskatchewan. This week, the Insect of the Week post features wheat stem sawfly, including information about how to estimate their population densities in the fall.

Diamondback moth, if present, are into the fourth non-migrant generation across most of the prairies now and could be starting a fifth generation in some southern parts of the prairies. Keep in mind that diamondback moth develop quickly in warm weather which could lead to rapidly increasing populations over the summer.

On the topic of diamondback moths, Dr. Maya Evenden’s lab at the University of Alberta is conducting research on diamondback moth, flea beetles, and alfalfa weevil. Learn more about Maya’s research program in this week’s Prairie Research post.

Use the links in the Provincial Insect Updates post to learn more about what is happening with populations of insect pests (and beneficial insects) in your province.

Remember:

1) There are many resources available to help with planning for late-season insecticide applications to ensure Pre-Harvest Interval requirements are met.

2) Insect Monitoring Protocols containing information about in-field scouting as well as information about insect pest biology and identification are available from the Prairie Pest Monitoring Network.

To receive Weekly Updates automatically, please subscribe to the website!

Questions or problems accessing the contents of this Weekly Update? Please contact Dr. Meghan Vankosky (meghan.vankosky@agr.gc.ca) to get connected to our information. Past Weekly Updates, full of information and helpful links, can be accessed on our Weekly Update page .

Predicted Diamondback Moth Development

Due to warm weather in 2023, development of diamondback moth populations is well ahead of average development. Model simulations to August 13, 2023, indicate that the fourth generation of non-migrant adults (based on early May arrival dates) are currently occurring across the Canadian prairies (Fig. 1) and that fifth generation non-migrant adults could also be occurring in some localized areas of the southern prairies.

In a ‘normal year’ based on climate normals data (e.g., 30-year averages), we would expect only the third generation of non-migrant diamondback moth to be occurring across the northern prairie region at this time of year, with the fourth generation occurring across the extreme southern region of the prairies (Fig. 2).

Considering advanced canola development, risk across the southern and central regions of the prairies associated with the development of a fifth generation of diamondback moth should be minimal. However, in regions where broccoli, rutabaga, and other brassica vegetables are grown and where crops are late to mature, these crops could still be at risk. Keep scouting for diamondback moth where crops are still green and could provide a desirable food source for developing diamondback moth larvae.

2023 Week 14 (Released August 10, 2023)

Insect scouting season continues! Development of many pest insects (and of their host crops) is ahead of schedule this year, thanks to warmer than average weather during this growing season.

Adult grasshoppers are now in flight and are expected to be busy reproducing across the prairie region. Scouting individual fields is important to best estimate crop risk. At this time of year, we start to look forward to next season. Insect surveyors are now working to estimate grasshopper populations in ditches/roadsides and may be collecting samples of adult grasshoppers for species identification.

Diamondback moth, if present, are into the fourth non-migrant generation across most of the prairies now. Keep in mind that diamondback moth develop quickly in warm weather which could lead to rapidly increasing populations over the summer.

Use the links in the Provincial Insect Updates post to learn more about what is happening with insect pest (and beneficial insect) populations in your province.

Remember: 1) there are many resources available to help with planning for late-season insecticide applications to ensure Pre-Harvest Interval requirements are met, and 2) insect Monitoring Protocols containing information about in-field scouting as well as information about insect pest biology and identification are available from the Prairie Pest Monitoring Network.

Finally, due to the long weekend and my departure for southern Saskatchewan early on Tuesday morning (to help with the aforementioned grasshopper survey), I wasn’t able to post the Insect of the Week until today. This week, we feature Aphidius spp. parasitoids, an important natural enemy of aphids.

To receive Weekly Updates automatically, please subscribe to the website!

Predicted Diamondback Moth Development

Due to warm weather in 2023, development of diamondback moth populations is well ahead of average development. Model simulations to August 6, 2023, indicate that the fourth generation of non-migrant adults (based on early May arrival dates) are currently occurring across the Canadian prairies (Fig. 1).

In a ‘normal year’ based on climate normals data (e.g., 30-year averages), we would expect only the third generation of non-migrant diamondback moth to be occurring at this time of the year.

Some areas of the prairies might be at risk of damage from diamondback moth this summer, based both on pheromone trap results for adult moths this spring and on the presence of high numbers of larvae in canola samples. Pheromone traps with cumulative counts greater than 25 male moths were located around Cadillac, Rosetown, Makwa, Eatonia, and Swift Current in Saskatchewan and in all regions of Manitoba (see the July 5 and July 19 editions of the Crop Pest Report). In Alberta, Shelley Barkley has found high numbers of diamondback moth larvae in canola samples from Yellowhead county, Parkland county, Lac St. Anne county, the Barrhead area, the Leduc area, and the Bonnyville area (so far).

Because diamondback moth can have multiple generations in a single growing season and because the generation time is shorter when temperatures are warm, their populations can build up quickly. Keep scouting for diamondback moth to avoid unpleasant surprises at the end of this summer.

2023 Week 13 (Released August 3, 2023)

Insect scouting season continues! Development of many pest insects (and of their host crops) is ahead of schedule this year, thanks to warmer than average weather during this growing season.

Between fieldwork and summer vacations, this Weekly Update is a short one. Thankfully, Shelley Barkley (Alberta Agriculture and Irrigation), James Tansey (Saskatchewan Ministry of Agriculture) and John Gavloski (Manitoba Agriculture) have kindly shared information about what they are seeing for insect pests in their respective prairie provinces.

Adult grasshoppers are now in flight and are expected to be busy reproducing across the prairie region. Scouting individual fields is important to best estimate crop risk. Information about grasshoppers and grasshopper monitoring is available from the Prairie Pest Monitoring Network, in the Field Crop and Forage Pests guide, Alberta Agriculture and Irrigation, Saskatchewan Ministry of Agriculture, and Manitoba Agriculture.

**Adult (brown with fully developed wings) and immature (green with wing ‘nubs’). Picture by Meghan Vankosky, AAFC-Saskatoon.**

Diamondback moth, if present, should now be well into their fourth generation across the prairies. As warm temperatures prevail, remember that diamondback moth develop from eggs to adults quickly and the population increases with each generation. Scout canola fields for diamondback moth larvae. To scout for diamondback moth, estimate the number of diamondback moth larvae per m² at several locations in a field. The economic threshold for diamondback moth is NOT based on pheromone traps or sweep net samples, but on the density of larvae per plant. For immature and flowering canola, the economic threshold is 100-150 larvae/m². In podded canola, the economic threshold is 200-300 larvae/m². See the Field Crop and Forage Pests guide and monitoring protocol for more information about scouting for diamondback moth.

Watch out for Invasive and Migrating Insects! If you suspect that you have found any of the insects on the Prairie Region Poster, please let us know using the form linked to the QR code on the poster. Note: many of us entomologists on the prairies are members of the Insect Surveillance Community of Practice!

On the topic of invasive insects, August is Tree Check Month! The Prairie Region Poster (and posters for BC, Ontario & Quebec, and Atlantic Canada) include invasive insect pests that could affect our forests in Canada.

Remember: 1) there are many resources available to help with planning for late-season insecticide applications to ensure Pre-Harvest Interval requirements are met, and 2) insect Monitoring Protocols containing information about in-field scouting as well as information about insect pest biology and identification are available from the Prairie Pest Monitoring Network.

To receive Weekly Updates automatically, please subscribe to the website!

Provincial Insect Updates

In Alberta, grasshopper population densities are high in the southeast and southcentral municipalities and the Agricultural Fieldmen are now starting to survey for adult grasshopper populations. There have been reports of wheat head armyworm in the central Peace River region, but there have also been Cotesia parasitoid cocoons in those fields, which is a good sign in terms of natural control of the armyworm population. Tiger moth caterpillars have also been reported in the central Peace River region; these are not typically pests but are interesting as they have been feeding on wild buckwheat.

Visit the Alberta Insect Pest Monitoring Network and Crop Insects pages for information about insects and monitoring in Alberta, including links for live maps from the 2023 monitoring season for diamondback moth, bertha armyworm, cutworms, and cabbage seedpod weevil.

Grasshopper densities are high in many parts of the prairies this year, especially now that adult grasshoppers are able to fly to disperse. With adults present, egg laying is likely to be underway. Picture by Jonathon Williams, AAFC-Saskatoon.

In Saskatchewan, grasshopper population densities are particularly high in the southern and central regions. Ripening canola crops are currently playing host to crickets (reported consuming pods), crucifer flea beetles, diamondback moth and Lygus bugs. Densities of diamondback moth and Lyugs have been economically significant in some regions, so scouting is important. Pea aphid and cereal aphid numbers appear to be increasing in some parts of the province, so scouting for these pests in their respective host crops is also important as the growing season winds down. There have been four reports of Hessian fly in Saskatchewan this summer.

Saskatchewan Crop Production News issues are now online! There are links on the Crop Production News page so that interested readers can subscribe to the newsletter or read issues from past years.

**A diamondback moth larva on a canola leaf. Population densities are high in some fields and scouting is needed to avoid unpleasant surprises. Picture by Jonathon Williams, AAFC-Saskatoon**.

In Manitoba, aphid population densities have been high enough to warrant control in small grain cereal crops in some regions, especially where crops were planted late and crops are still in vulnerable stages. Where there are a lot of aphids in fields, there have also been lots of lady beetle larvae and aphid mummies (resulting from aphids being attacked by parasitoids). A few fields in the Cypress River/Balder area of Manitoba have been sprayed for bertha armyworm. Some canola fields have been sprayed for diamondback moth and Lygus bugs in the Eastern region, and for diamondback moth in the Interlake region. Like in Saskatchewan, crucifer flea beetles are now active again, and are feeding on green canola. A soybean field in the Central region of Manitoba was treated for spider mites. Some insecticide applications for banded sunflower moth have occurred in the Eastern region. Grasshoppers are numerous in crops in some areas, and pastures in some areas have been sprayed for grasshoppers. John spotted some dead grasshoppers clinging to the upper leaves of plants that were infected with the pathogen Entomophaga grylii, but the incidence of infection has been low so far this year. Scout for aphids in cereal crops and for a variety of insects in canola fields.

Weekly Manitoba Crop Pest Updates for 2023 are available online with timely updates about insect pests, weeds, and plant pathogens. Watch their website for new Crop Pest Updates (usually published on Wednesdays this year).

Prairie Research

*This text was prepared by Kanishka Seneveirathna, Natalie LaForest, and Boyd Mori from the University of Alberta

Under the supervision of Dr. Boyd Mori at the University of Alberta, the ecological and agricultural entomology lab employs diverse molecular methods to tackle pest-related problems and develop integrated pest management approaches. Here we highlight research conducted by two graduate students: Kanishka Seneveirathna and Natalie LaForest.

Kanishka’s research uses population genetics to detect and monitor invasive insects in the prairie ecosystem. His research focuses on reconstructing the invasion routes of wheat midge (Sitodiplosis mosellana) and diamondback moth (Plutella xylostella), two devastating pests, by determining their origins in North America. To understand their invasion patterns, Kanishka employs a genomic approach (RADSeq), which allows for genome-wide population structure analysis.

A pheromone trap (left) used to collect adult wheat midge for population genetic analyses. The adult midge are trapped on a sticky card (right). Pictures by Kanishka Seneveirathna, University of Alberta.

By reconstructing the invasion routes of these pests, Kanishka aims to identify their origins and determine the genetic diversity and structure of different populations. This comprehensive understanding will facilitate the development of integrated pest management strategies, including forecasting systems and insecticide resistance management strategies. Initial findings indicate multiple independent invasion events for wheat midge across North America.

Moving forward, Kanishka and the Mori Lab team will work with members of the PPMN to collect a larger number of samples across the Prairies, ensuring comprehensive coverage. Collaboration with international research groups is also on the agenda, enabling the validation of findings and broader knowledge exchange. The goal is to develop effective management strategies to mitigate the damage caused by these invasive pests and enhance the productivity and quality of canola and wheat crops in the Canadian Prairies.

Pheromone traps (A) are used to collect adult diamondback moths in canola fields. Once trapped, the moths are removed from the sticky cards that are placed on the floor of the pheromone trap (B). To collect diamondback moth larvae for population genetic analyses, canola is sampled using sweep nets (C). **Pictures by Kanishka Seneveirathna, University of Alberta.**

Natalie’s research focuses on integrated pest management, more specifically the ecosystem service of weed seed predation performed by ground beetles (Coleoptera: Carabidae). Previous research on determining the species of weeds consumed by this group of beneficial insects have used seed cards in the field or cafeteria choice tests in the laboratory. Natalie’s work uses a multiplex-PCR approach, where she uses the DNA found within the gut of field captured ground beetles to determine what the ground beetles are consuming in the field. She is designing species-specific primers of agronomic significant weeds to decipher this significant predator-prey interaction.

Throughout the 2021 and 2022 seasons, the most abundant ground beetle species collected has been Pterostichus melanarius, which is an introduced, opportunist generalist predator. Natalie is focusing on ground beetles in wheat and industrial hemp, but there are other members in the Mori lab looking at the prey items of ground beetles in canola and pulses. Identifying species specific predator-prey interactions will development more sustainable pest management strategies for producers.

A pitfall trap full of adult ground beetles (Coleoptera: Carabidae); pitfall traps are used to collect ground beetles and other insects during the growing season. Picture by Natalie LaForest, University of Alberta.

Predicted Diamondback Moth Development

A fourth generation of non-migrant adult diamondback moths could be flying right now in southern Manitoba and in southeastern Alberta (Fig. 1). This prediction is based on model simulations to July 23, 2023 using early May arrival dates for diamondback moth adults that migrated into western Canada in the spring.

**Figure 1. Predicted number of non-migrant generations of diamondback moth (*Plutella xylostella*) expected to have occurred (or be occurring) across the Canadian prairies as of July 23, 2023.**

Compared to past years, warm weather in 2023 has sped up the development of diamondback moth. Using long-term average weather data (also known as climate normal data), model simulations to July 23 indicate that a second or third non-migrant generation of diamondback moth should be occurring right now (Fig. 2). In 2023, we could already be seeing a fourth generation!

**Figure 2. The number of non-migrant generations of diamondback moth (*Plutella xylostella*) expected to have occurred across the Canadian prairies as of July 23, based on climate normal data.**

Some areas of the prairies might be at risk of damage from diamondback moth this summer. Pheromone traps with cumulative counts greater than 25 male moths were located around Cadillac, Rosetown, Makwa, Eatonia, and Swift Current in Saskatchewan and in all regions of Manitoba (see the July 5 and July 19 editions of the Crop Pest Report). In Alberta, Shelley Barkley is finding diamondback moth larvae in canola samples from Yellowhead county, Parkland county, the Leduc area, and the Bonnyville area.

PARASITOIDS OF DIAMONDBACK MOTH

This week, our insects of the week are the natural enemies of diamondback moth found on the Prairies! Four important parasitoids attack this pest: Diadegma insulare, Diadromus subtilicornis, Microplitis plutellae, and Trichogramma praetiosum.

**A pupa of the parasitoid *Diadegma insulare* inside its cocoon. Picture credit: Andrea Brauner, AAFC.**

Some of these species (like Diadegma insulare) follow diamondback moth on its yearly migration from the southern United States and some (like Micropletis plutellae) overwinter in Canada and can help with early-season control. These small, dark colored wasps occasionally completely control diamondback moth outbreaks in Canada!

**Parasitoids of diamondback moth. On the left: *Diadegma insulare*. On the right: *Microplitis plutellae*. Both pictures taken by Amanda Jorgensen, AAFC-Beaverlodge Research Farm.**

The four parasitoid species attack during different stages of the diamondback moth lifecycle. Diadegma and Micropletis parasitoids attack larval diamondback moth. Trichogramma and Diadromus species attack the prepupal and pupal stages.

**A female *Diadromus* parasitoid preparing to parasitize a diamondback moth pupa. Picture credit: Andrea Brauner, AAFC.**

There is a long list of other wasp species that have been found to parasitize diamondback moth larvae to a lesser extent. Hoverfly larvae, yellowjacket wasps, lacewings, plant bugs, pirate bugs, beetles, spiders and birds also prey on diamondback moth larvae.

Biological and monitoring information related to diamondback moths in field crops can be found on our Monitoring page as well as on provincial Agriculture Ministry pages (Manitoba, Saskatchewan and Alberta). For more information, visit the diamondback moth page in the Field Crop and Forage Pests and their Natural Enemies in Western Canada: Identification and Management field guide. (en français : Guide d’identification des ravageurs des grandes cultures et des cultures fourragères et de leurs ennemis naturels et mesures de lutte applicables à l’Ouest canadien). You can find more information about some of the parasitoids of diamondback moth on the field heroes website or learn about Braconid wasp life cycles here.

Predicted Diamondback Moth Development

In summer 2023, diamondback moth development is well ahead of average. Model simulations to July 16, 2023, indicate that the third generation of non-migrant adults (based on early May arrival dates) is currently occurring across the Canadian prairies (Fig. 1).

When we ran the model using long term average weather data (based on climate normals), the model output showed that the second generation of diamondback moth would be occurring at this date in a ‘normal’ year (Fig. 2). Above normal temperatures in 2023 have increased the rate of diamondback moth development, resulting in three generations in the time it usually takes for the development of two generations!

Some areas of the prairies might be at risk of damage from diamondback moth this summer. Pheromone traps with cumulative counts greater than 25 male moths were located around Cadillac, Rosetown, Makwa, Eatonia, and Swift Current in Saskatchewan, in the Vulcan area in Alberta, and in all regions of Manitoba (data in the July 5 Crop Pest Update). According to the July 19 edition of the Manitoba Crop Pest Update, canola fields in the Plum Coulee, St. Joseph and Dominion City areas of Manitoba had high levels of diamondback moth larvae in the last week. Because diamondback moth can have multiple generations in a single growing season and because the generation time is shorter when temperatures are warm, their populations can build up quickly. Keep scouting for diamondback moth to avoid unpleasant surprises at the end of this summer.

DIAMONDBACK MOTH

The diamondback moth (Plutella xylostella) is an invasive species that migrates northward to the Canadian Prairies on wind currents from infested regions in the USA. Upon arrival, migrant diamondback moths begin to reproduce, resulting in non-migrant populations that may have three or four generations on the prairies during the growing season. The time required for diamondback moth to complete a generation gets shorter when temperatures are warm. In warmer years, diamondback moth populations can build up relatively quickly, increasing their chances of causing economic damage to crops where populations are present. Host plants of diamondback moth include canola, mustard and other cruciferous vegetables and weeds.

Diamondback moths lay their eggs on leaves. Hatchling larvae emerge and tunnel into the leaves, later moving to the surface to feed. Damage first appears as shot holes but eventually expands until the leaves are skeletonized, leaving only the leaf veins. Larvae also feed on flowers and strip the surface of developing pods and stems. Larval damage lowers seed quality and crop yield of canola and can affect the marketability of crucifer vegetables.

The lifecycle of diamondback moth: A) eggs, B) early instar larva with damage typical of this life stage, C) late instar larva on a skeletonized leaf, D) pupa, and E) adult moth. All pictures taken by Jonathon Williams, AAFC-Saskatoon.

Adult moths measure 12 millimeters long with an 18-20 millimeter wingspan. At rest, their forewings form a diamond-shaped pattern along the mid-line. Mature larvae are 8-millimetre-long green caterpillars. Their terminal prolegs extend backwards, resembling a fork. When disturbed, caterpillars drop towards the ground on a silken thread to avoid harm.

Biological and monitoring information related to diamondback moths in field crops can be found on our Monitoring page as well as on provincial Agriculture Ministry pages (Manitoba, Saskatchewan and Alberta). For more information, visit the diamondback moth page in the Field Crop and Forage Pests and their Natural Enemies in Western Canada: Identification and Management field guide. (en français: Guide d’identification des ravageurs des grandes cultures et des cultures fourragères et de leurs ennemis naturels et mesures de lutte applicables à l’Ouest canadien).

Diamondback Moth

Diamondback moths are a migratory invasive species; in 2023, the first migratory adults were found in pheromone traps in early May. Thanks to the above average warm weather across most of the prairie region this year, diamondback moth development is well ahead of average. Based on development models and weather to July 2, a third generation of non-migrant adults is expected to be occurring in some parts of the prairies (Fig. 1), with the second generation occurring in nearly all other areas of the prairies (Fig. 1).

Diamondback moth typically have 4 full generations during prairie summers. In an average year, we would expect that the second generation of non-migrant diamondback moth would we widespread right now, NOT the third non-migrant generation (Fig. 2).

Figure 2. Number of non-migrant generations of diamondback moth (*Plutella xylostella*) expected to have occurred across the prairie region by early July in a ‘normal’ year (based on 30-year average or long-term normal weather data).

Some areas of the prairies might be at risk of damage from diamondback moth. Pheromone traps with cumulative counts greater than 25 male moths so far in 2023 are located around Cadillac, Rosetown, Makwa, Eatonia, and Swift Current in Saskatchewan, in the Vulcan area in Alberta, and in all regions of Manitoba (see the July 5 Manitoba Crop Pest Update). In Manitoba, the highest counts of diamondback moths in pheromone traps exceed 200 total moths in the Central and Eastern regions. Because diamondback moth can have multiple generations in a single growing season and because the generation time is shorter when temperatures are warm, their populations can build up quickly. Keep scouting for diamondback moth to avoid unpleasant surprises later this summer.

Grasshoppers, bertha armyworm, and diamondback moth

Grasshoppers

Development of the pest grasshoppers continues to be ahead of schedule in 2023, as compared to past years. The first adult two-striped grasshoppers (Melonplus bivittatus) were collected on June 15 (Alberta) and June 19-20 (Saskatchewan). No one that we’ve spoken to remembers finding adult two-striped grasshoppers in June before. Especially in the south, densities are quite high and crop damage is being reported, as well as spraying to protect crops.

Model simulations for grasshopper development indicate that grasshoppers should range from first to fifth instars with some adults now present at many locations across the prairies, as of June 25. Based on average instar, development is most advanced across the southern prairies where 65% of the population is predicted to be fourth and 5th instar, with some adults also present (Fig. 1). In an ‘average year’, the majority of the grasshopper population (60%) would typically be in the first, second, and third instars in late June.

**Figure 1. Predicted grasshopper (*Melanoplus sanguinipes*) development, presented as average instar, across the Canadian prairies as of June 25, 2023.**

Based on occurrence of fifth instar grasshoppers, development is most advanced across southern Manitoba (Fig. 2).

**Figure 2. Predicted migratory grasshopper (Melanoplus sanguinipes) development, presented as the percent of the population in the fifth instar, across the Canadian prairies as of June 25, 2023.**

Adult two-striped grasshoppers (Melanoplus bivittatus) and migratory grasshoppers (M. sanguinipes) have been observed across the southern prairies.

Information about grasshoppers and grasshopper monitoring is available from the Prairie Pest Monitoring Network, in the Field Crop and Forage Pests guide, Alberta Agriculture and Irrigation, Saskatchewan Ministry of Agriculture, and Manitoba Agriculture.

Bertha armyworm

Last week, models predicted that first instar bertha armyworm larvae might be present in some areas of the prairies. Bertha armyworm larvae could also be developing quickly, thanks to warm weather. The network of pheromone traps across the prairies is reporting low numbers of adults (less than 300 cumulative catch), including in Manitoba (check out the June 21 Manitoba Crop Pest Update) and Alberta. Risk to yield from bertha armyworm increases when cumulative trap catches exceed 300 (300-900 = medium risk, >900 = high risk). For information about scouting, check out the PPMN protocol and the Alberta Agriculture and Irrigation pages.

Diamondback moth

Some areas of the prairies might be at risk of damage from diamondback moth; pheromone traps with cumulative counts greater than 25 male moths so far in 2023 are located around Rosetown and Swift Current in Saskatchewan, in the Vulcan area in Alberta, and in the Central, Eastern, and Interlake regions in Manitoba (see the June 21 Manitoba Crop Pest Update). Like grasshoppers and bertha armyworm, diamond back moth development occurs quickly in warm weather. Last week, we predicted that diamondback moths had reached the second non-migrant generation and we heard of some sightings of larvae in some areas of the prairies. Because diamondback moth can have multiple generations in a single growing season, their populations can build up quickly. Keep scouting for diamondback moth to avoid unpleasant surprises later this summer.

Predicted Diamondback Moth Development

Diamondback moths (Plutella xylostella) were first found on pheromone traps across western Canada in early May in 2023. After the first migrant adults arrive, there can be multiple non-migrant populations of diamondback moth, with the population density potentially increasing with each generation. Average development, based on climate normals, suggests that diamondback moths should be in the first non-migrant generation. However, diamondback moth development can be rapid during periods of warm weather, such as we have experienced across most of western Canada so far this spring. As a result, model simulations to June 18, 2023, indicate that prairie diamondback moth populations are now in the second non-migrant generation (Fig. 1).

Local scouting is needed to determine if diamondback moths pose a threat to crops. To scout, estimate the number of diamondback moth larvae per m² at several locations in a field. The economic threshold for diamondback moth is NOT based on pheromone traps or sweep net samples, but on the density of larvae per plant. For immature and flowering canola, the economic threshold is 100-150 larvae/m². In podded canola, the economic threshold is 200-300 larvae/m². See the Field Crop and Forage Pests guide and monitoring protocol for more information about scouting for diamondback moth.

**The life stages of diamondback moth: A) eggs, B) early instar larva, C) later instar larva, D) pupa, and E) adult. Picture credit: Jonathon Williams, AAFC-Saskatoon.**

Predicted Diamondback Moth Development

Diamondback moth development can be rapid during periods of warm weather. Model simulations to June 11, 2023, indicate that the second generation of non-migrant adults (based on early-May arrival dates) is currently occurring across the southern prairies (Fig. 1).

On the prairies, we use a network of pheromone traps to detect the first spring appearance of diamondback moths. In the June 7 and June 14 issues of the Manitoba Crop Pest Update, some diamondback moth trap locations in the central and eastern parts of the province reported catching between 100-200 adult moths. At least three sites in central and southern Alberta (use the link to see the live map) have also caught between 100-200 moths so far this year. Lower numbers have been recorded so far in Saskatchewan in 2023.

Now, local scouting is needed to determine if diamondback moths pose a threat to crops. To scout, estimate the number of diamondback moth larvae per m² at several locations in a field. The economic threshold for diamondback moth is NOT based on pheromone traps or sweep net samples, but on the density of larvae per plant. For immature and flowering canola, the economic threshold is 100-150 larvae/m². In podded canola, the economic threshold is 200-300 larvae/m². See the Field Crop and Forage Pests guide and monitoring protocol for more information about scouting for diamondback moth.

2023 Week 5 (Released June 8, 2023)

Insect scouting and monitoring season is getting into full swing!

Weather patterns in May and so far in June have been perfect for the development of some insect pests, but suboptimal for others. However, it is hard to generalize, as some parts of the prairies have been wet and others dry. Similarly, some areas have been very warm, while others have been cooler. This year it will be very important to scout and to monitor insect populations at the field-scale.

Grasshoppers thrive in warm, dry conditions. This week, some 4th instar nymphs were spotted in ditches in southwestern Saskatchewan, although there are many first, second and some third instar nymphs as well. Signs of damage are starting to appear. Overall grasshopper development continues to be ahead of schedule and two-striped grasshoppers continue to be prevalent.

Diamondback moths that arrived in early May have likely reproduced and adult moths found now could be from the first generation produced on the prairies. Diamondback moths develop rapidly when it is warm and their population densities can build up quickly with each generation. Be ready to scout if pheromone traps in your area have detected diamondback moths this spring.

Bertha armyworm development is also well ahead of schedule – pupal development could be 90% complete in some areas and adult moths could already be flying around. Watch the provincial websites in Alberta, Saskatchewan, and Manitoba for reports on bertha armyworm pheromone trap captures for your area over the next few weeks.

This week, the Insect of the Week featured ground beetles and rove beetles! Both can prey on different life stages of the pea leaf weevil and on other insect pests (and slugs!).

Please read this week’s posts in the Weekly Update for more information about the insects listed above and for a sneak peak of wheat midge development!

Remember, insect Monitoring Protocols containing helpful insect pest biology, how and when to plan for in-field scouting, and economic thresholds to help support in-field management decisions. All are available to read or download for free!

To receive Weekly Updates automatically, please subscribe to the website!

Predicted diamondback moth development

Diamondback moths (Plutella xylostella) are a migratory invasive species; after initial migration into the prairies, diamondback moths can have multiple non-migratory generations during the growing season. Diamondback moth development can be rapid during periods of warm weather. Model simulations to June 4, 2023, indicate that the first generation of non-migrant adults (based on early-May arrival dates) is currently occurring across the Canadian prairies. If above-normal temperatures persist, then we may start to see some second-generation diamondback moths next week.

**The life cycle of diamondback moth can rapidly progress from egg (A) to larvae (B and C), to pupae (D) to adults (E). Photo credit: Jonathon Williams, AAFC-Saskatoon.**

On the prairies, we use a network of pheromone traps to detect the first spring appearance of diamondback moths. Now, local scouting is needed to determine if diamondback moth pose a threat to crops. To scout, estimate the number of diamondback moth larvae per m² at several locations in a field. The economic threshold for diamondback moth is NOT based on pheromone traps or sweep net samples, but on the density of larvae per plant. For immature and flowering canola, the economic threshold is 100-150 larvae/m². In podded canola, the economic threshold is 200-300 larvae/m². See the Field Crop and Forage Pests guide and monitoring protocol for more information about scouting for diamondback moth.

Predicted diamondback moth development

Diamondback moths (Plutella xylostella) are a migratory invasive species to western Canada. Each spring adult populations migrate northward to the Canadian prairies on wind currents from infested regions in the southern or western U.S.A. Upon arrival to the prairies, migrant diamondback moths begin to reproduce, resulting in subsequent non-migrant populations that may have three or four generations during the growing season. DBM development can be rapid during periods of warm weather. Model simulations, initiated in early May and extending to May 28, 2023, indicate that the first generation of non-migrant adults are currently occurring across the Canadian prairies (Fig. 1).

In-Field Monitoring: Remove plants in an area measuring 0.1 m² (about 12″ square), beat them onto a clean surface and count the number of larvae dislodged from the plant. Repeat this procedure at least in five locations in the field to get an accurate count.

Biological and monitoring information for diamondback moth (including tips for scouting and economic thresholds) is posted by Manitoba Agriculture, Saskatchewan Ministry of Agriculture, and the Prairie Pest Monitoring Network. Also, refer to the diamondback moth pages within the “Field Crop and Forage Pests and their Natural Enemies in Western Canada: Identification and management field guide” (2018) accessible as a free downloadable PDF in either English or French on our Field Guides page.

Predicted diamondback moth development

Analysis of wind trajectory data (from Environment and Climate Change Canada) indicates that a number of upper air currents, originating over the USA Pacific Northwest, passed over Alberta and Saskatchewan during the last week of April and first three weeks of May. These wind currents could have been carrying adult diamondback moths into the prairies. In fact, adult diamondback moths have been collected in traps located across Alberta (information courtesy of Shelley Barkley, Alberta Agriculture and Irrigation) and Saskatchewan (information courtesy of Carter Peru and James Tansey, Saskatchewan Ministry of Agriculture) during the first three weeks of May.

DBM development can be rapid during periods of warm weather. This week, the diamondback moth model was initialized for May 1, 2023 and run to May 21. Though canola may not be present, model results indicate that females may have begun to lay eggs on cruciferous plants like volunteer canola and weeds. Larvae could now also be found feeding on these host plants. The model simulation indicates that populations near Grande Prairie, AB (Fig. 1) are likely to be more advanced in terms of development than populations near Cadillac, SK (Fig. 2) reflecting differences in growing season weather so far in 2023 at the two locations.

**Figure 1. Predicted development of diamondback moth (*Plutella xylostella*) near Grande Prairie, AB as of May 21, 2023.**

**Figure 2. Predicted development of diamondback moth (*Plutella xylostella*) near Cadillac, SK as of May 21, 2023 (Biofix date = May 1, 2023).**

Spring Pheromone Trap Monitoring of Adult Males: Across the Canadian prairies, spring monitoring is initiated to acquire weekly counts of adult moths attracted to pheromone-baited delta traps deployed in fields. Weekly trap interceptions are observed to generate cumulative counts. Summaries or maps of cumulative male diamondback moth counts will be available for each province as the monitoring season progresses. These cumulative count estimates are broadly categorized to help producers prioritize and time in-field scouting for larvae.

The life stages of diamondback moth, *Plutella xylostella*: (A) eggs, (B) early instar larva, (C) late instar larvae, (D) pupa, and (E) adult moth. Photo credit: Jonathon Williams, AAFC-Saskatoon (all pictures)

Biological and monitoring information for DBM (including tips for scouting and economic thresholds) is posted by Manitoba Agriculture, Saskatchewan Ministry of Agriculture, and the Prairie Pest Monitoring Network. Also, refer to the diamondback moth pages within the “Field Crop and Forage Pests and their Natural Enemies in Western Canada: Identification and management field guide” (2018) accessible as a free downloadable PDF in either English or French on our Field Guides page.

Predicted Diamondback Moth Development

It has been suggested the overwintering mortality of diamondback moth (DBM) is high on the prairies. DBM, carried on upper air currents, may be introduced to the prairies from overwintering sites in southern USA and the US Pacific Northwest. Analysis of wind trajectory data (from Environment and Climate Change Canada) indicated that a number of upper air currents, originating over the US Pacific Northwest, passed over the Peace River region during the last week of April and first two weeks of May. DBM development can be rapid during periods of warm weather. Shelley Barkley (Alberta Agriculture and Irrigation) reports that DBM adults have been collected from a number of traps across Alberta. In Alberta, trap captures of DBM have been highest near Grande Prairie. Similarly, Carter Peru and James Tansey (Saskatchewan Ministry of Agriculture) note that adult DBM have been collected on traps located across Saskatchewan.

During the growing season, results from the DBM monitoring program in Saskatchewan will be available here (scroll to the bottom of the page) and results from Alberta will be available here.

DBM were collected during the first and second weeks of May. Thus, the DBM model was initialized for May 1, 2023 and run to May 14. Though canola may not be present, results indicate that females may have started to lay eggs on brassicaceous plants (e.g., volunteer canola, flix weed) and larvae may have hatched from early-laid eggs. In the Grande Prairie area, for example, both eggs and first instar larvae may already be present (Fig. 1).

**Figure 1. Predicted development of diamondback moth (*Plutella xylostella*) near Grande Prairie, AB as of May 14, 2023.**

Weekly Wind Trajectory Report for June 27

Access background information on how and why wind trajectories are monitored. Reverse and forward trajectories are available in this report.

1. REVERSE TRAJECTORIES (RT)
Since May 1, 2022, the majority of reverse trajectories that have crossed the prairies have originated from the Pacific Northwest (Idaho, Oregon and Washington). This past week (June 21-27, 2022) the number of incoming trajectories was lower than the week of June 14-20, 2022 (Fig. 1).

Figure 1. Average number (based on a 5-day running average) of reverse trajectories (RT) crossing the prairies for the period of **June 1-27, 2022**.

a. Pacific Northwest (Idaho, Oregon, Washington) – The majority of Pacific Northwest reverse trajectories continue to pass over southern and central Alberta and western Saskatchewan (Fig. 2). This past week (June 21-27, 2022) the ECCC model predicted that 77 reverse trajectories would cross the prairies. This is significantly less than the number of reverse trajectories predicted for the period of June 14-20 (n=124).

Figure 2. Total number of dates with reverse trajectories originating over the Idaho, Oregon, and Washington that have crossed the prairies between April 1 and June 27, 2022.

b. Mexico and southwest USA (Texas, California) – This week (June 21-27, 2022), a total of 13 reverse trajectories were predicted to cross the prairies (n=44 for June 14-20). Most reverse trajectories from this region of southern North America have crossed Manitoba during the 2022 growing season.

Figure 3. The total number of dates with reverse trajectories originating over Mexico, California and Texas that have crossed the prairies between April 1 and June 27, 2022.

c. Oklahoma and Texas – This week reverse trajectories have passed over Manitoba and Watrous, Saskatchewan (Fig. 4). This week there were significantly fewer (n=5) reverse trajectories than for the period of June 14-20, 2022 (n=33).

Figure 4. The total number of dates with reverse trajectories originating over Texas and Oklahoma that have crossed the prairies between May 1 and June 27, 2022.

d. Nebraska and Kansas – This past week (June 21-27, 2022), reverse trajectories originating from Kansas and Nebraska have crossed Manitoba and Yorkton, Saskatchewan (Fig. 5). The ECCC model predicted that 5 reverse trajectories passed over the prairies. This is a significant decrease from the previous week (n=51).

Figure 5. The total number of dates with reverse trajectories originating over Kansas and Nebraska that have crossed the prairies between April 1 and June 27, 2022.

2. FORWARD TRAJECTORIES (FT)
The following map presents the total number of dates (since April 1, 2022) with forward trajectories (originating from Mexico and USA) that were predicted to cross the Canadian prairies (Fig. 6). This week (June 21-27, 2022) there was a decrease in the number of (n=19) forward trajectories predicted to cross the prairies (last week n=50). Results indicate that the greatest number of forward trajectories entering the prairies have originated from the Pacific Northwest (Idaho, Oregon, Washington), Montana and Wyoming.

Figure 6. Total number of dates with forward trajectories, originating from various regions of the United States and Mexico, crossing the prairies between **April 1 and June 27, 2022**.

View historical PPMN wind trajectory reports by following this link which sorts the reports from most recent to oldest.

Weekly Wind Trajectory Report for June 13

Access background information on how and why wind trajectories are monitored. Reverse and forward trajectories are available in this report.

1. REVERSE TRAJECTORIES (RT)
Since May 1, 2022, the majority of reverse trajectories that have crossed the prairies originated from the Pacific Northwest (Idaho, Oregon and Washington) (Fig. 1). This past week (June 7-13, 2022) the number of reverse trajectories originating from Mexico, California, Texas, Oklahoma, Nebraska and Kansas continued to be low. This week reverse trajectories generally originated over the Pacific Ocean before entering the prairies.

Figure 1. Average number (based on a 5-day running average) of reverse trajectories (RT) crossing the prairies for the period of **June 1-13, 2022**.

a. Pacific Northwest (Idaho, Oregon, Washington) – The majority of Pacific Northwest reverse trajectories have been reported to pass over southern and central Alberta and western Saskatchewan (Fig. 2). This past week (June 7-13, 2022) the ECCC model predicted that 134 reverse trajectories would cross the prairies. This is a significant increase over the previous week (n=26).

b. Mexico and southwest USA (Texas, California) – This past week (June 7-13, 2022) the model reported that zero reverse trajectories that originated from Mexico, California or Texas crossed over the Canadian prairies. Since May 1, 2022, these trajectories have been restricted to Manitoba and eastern Saskatchewan (Fig. 3).

c. Oklahoma and Texas – Since April 1, reverse trajectories were reported for Manitoba and eastern Saskatchewan. This past week (June 7-13, 2022) one trajectory crossed over Edmonton, Alberta.

d. Nebraska and Kansas – Until this week, reverse trajectories originating from Kansas and Nebraska have been associated with southeastern Saskatchewan and southern Manitoba (Fig. 5). This past week (June 7-13, 2022) the ECCC model predicted that 8 reverse trajectories passed over the prairies. Six of these reverse trajectories passed over parts of Alberta, including Beiseker, Olds, Edmonton, Rycroft, and Fort Vermilion and Fort St. John in British Columbia.

2. FORWARD TRAJECTORIES (FT)
The following map presents the total number of dates (since April 1, 2022) with forward trajectories (originating from Mexico and USA) that were predicted to cross the Canadian prairies (Fig. 6). This week (May 31 to June 6, 2022) there The following map presents the total number of dates (since April 1, 2022) with forward trajectories (originating from Mexico and USA) that were predicted to cross the Canadian prairies (Fig. 6). This week (June 7-13, 2022) there was an increase in the number of forward trajectories (n=34) predicted to cross the prairies compared to last week (n=12). Results indicate that the greatest number of forward trajectories entering the prairies have originated from the Pacific Northwest (Idaho, Oregon, Washington), Montana and Wyoming.

View historical PPMN wind trajectory reports by following this link which sorts the reports from most recent to oldest.

Weekly Wind Trajectory Report for June 6

Access background information on how and why wind trajectories are monitored. Reverse and forward trajectories are available in this report.

1. REVERSE TRAJECTORIES (RT)
Since May 1, 2022 the majority of reverse trajectories that have crossed the prairies originated from the Pacific Northwest (Idaho, Oregon and Washington) (Fig. 1). Relative to previous weeks, there was a significant decrease in the number of trajectories that were predicted to cross over the prairies from May 31 – June 6, 2022. This week reverse trajectories generally originated over the arctic before entering the prairies.

Figure 1. Average number (based on a 5-day running average) of reverse trajectories (RT) crossing the prairies for the period of **May 1-June 6, 2022**.

a. Pacific Northwest (Idaho, Oregon, Washington) – The majority of Pacific Northwest reverse trajectories have been reported to pass over southern and central Alberta and western Saskatchewan (Fig. 2). This past week (May 31-June 6, 2022) the ECCC model predicted that 26 reverse trajectories passed over the prairies. This is a significant decrease compared to the previous week (n=124).

b. Mexico and southwest USA (Texas, California) – This past week (May 31 to June 6, 2022) reverse trajectories that originated from Mexico, California or Texas crossed over Carman and Selkirk (May 31, 2022). Since April 1, reverse trajectories were reported for Manitoba (Portage, Selkirk, Brandon, Carman, Russell) and eastern Saskatchewan (Gainsborough, Grenfell) (Fig. 3).

c. Oklahoma and Texas – Since April 1, reverse trajectories were reported for Manitoba and eastern Saskatchewan (Fig. 4). This past week (May 31 to June 6, 2022) there has been an increase in the number of reverse trajectories that have crossed over southeastern Saskatchewan (Weyburn and Gainsborough) and Manitoba (Portage and Brandon).

d. Nebraska and Kansas – Reverse trajectories, originating from Kansas and Nebraska, have crossed southeastern Saskatchewan and southern Manitoba (Fig. 5). This past week (May 31 to June 6, 2022) the ECCC model predicted that 6 reverse trajectories passed over the prairies. This is a significant decrease compared to the previous week (n=27).

View historical PPMN wind trajectory reports by following this link which sorts the reports from most recent to oldest.

Weekly Wind Trajectory Report for May 30

Access background information on how and why wind trajectories are monitored. Reverse and forward trajectories are available in this report.

1. REVERSE TRAJECTORIES (RT)
Since May 1, 2022, the majority of reverse trajectories crossing the prairies originated from the Pacific Northwest (Idaho, Oregon and Washington) (Fig. 1). Relative to previous weeks, this past week (May 24-30, 2022) there was a significant increase in the number of trajectories (PNW, OK/TX and NE/KS) that passed over the prairies.

Figure 1. Average number (based on a 5-day running average) of reverse trajectories (RT) crossing the prairies for the period of **May 1-30, 2022**.

b. Mexico and southwest USA (Texas, California) – This past week there have not been any reverse trajectories that originated from Mexico, California or Texas. Since April 1, reverse trajectories were reported for Manitoba (Portage, Selkirk, Brandon, Carman, Russell) and eastern Saskatchewan (Gainsborough, Grenfell) (Fig. 3).

c. Oklahoma and Texas – Since April 1, reverse trajectories were reported for Manitoba and eastern Saskatchewan (Fig. 4). This past week (May 24-30, 2022) there was an increase in the number of reverse trajectories that have crossed over southeastern Saskatchewan (Weyburn and Gainsborough) and Manitoba (Portage and Brandon) relative to previous weeks.

d. Nebraska and Kansas – Reverse trajectories, originating from Kansas and Nebraska have crossed southeastern Saskatchewan and southern Manitoba (April 1 – May 23, 2022) (Fig. 5). This past week (May 24-30, 2022) there was an increase in the number of reverse trajectories that have crossed over eastern Saskatchewan and Manitoba relative to previous weeks.

2. FORWARD TRAJECTORIES (FT)
The following map presents the total number of dates (since April 1, 2022) with forward trajectories (originating from Mexico and USA) that were predicted to cross the Canadian prairies (Fig. 6). Results indicate that the greatest number of forward trajectories entering the prairies have originated from the Pacific Northwest (Idaho, Oregon, Washington), Montana and Wyoming.

View historical PPMN wind trajectory reports by following this link which sorts the reports from most recent to oldest.

Weekly Wind Trajectory Report for May 23

Access background information on how and why wind trajectories are monitored. Reverse and forward trajectories are available in this report.

1. REVERSE TRAJECTORIES (RT)
Since May 1, 2022, the majority of reverse trajectories that have crossed the prairies originated from the Pacific Northwest (Idaho, Oregon and Washington) (Fig. 1). Relative to previous weeks, this past week (May 17-23, 2022) there were fewer trajectories passing over the prairies.

Figure 1. Average number (based on a 5-day running average) of reverse trajectories (RT) crossing the prairies for the period of **May 1-23, 2022**.

b. Mexico and southwest USA (Texas, California) – This past week there were no reverse trajectories originating from Mexico, California or Texas. Since April 1, reverse trajectories were reported for Manitoba (Portage, Selkirk, Brandon, Carman, Russell) and eastern Saskatchewan (Gainsborough, Grenfell) (Fig. 3).

c. Oklahoma and Texas – Since April 1, reverse trajectories were reported for Manitoba and eastern Saskatchewan (Fig. 4). No trajectories were predicted for May 17-23, 2022.

d. Nebraska and Kansas – Reverse trajectories, originating from Kansas and Nebraska have crossed southeastern Saskatchewan and southern Manitoba (April 1 – May 23, 2022) (Fig. 5).

2. FORWARD TRAJECTORIES (FT)
The following map presents the total number of dates (since April 1, 2022) with forward trajectories (originating from Mexico and USA) predicted to cross the Canadian prairies (Fig. 6). Results indicate that the greatest number of forward trajectories entering the prairies have originated from the Pacific Northwest (Idaho, Oregon, Washington), Montana and Wyoming.

Weekly Wind Trajectory Report for May 16

Access background information on how and why wind trajectories are monitored. Reverse and forward trajectories are available in this report.

1. REVERSE TRAJECTORIES (RT)
Since May 1, 2022, the majority of reverse trajectories crossing the prairies originated from the Pacific Northwest (Idaho, Oregon and Washington) (Fig. 1).

Figure 1. Average number (based on a 5-day running average) of reverse trajectories (RT) crossing the prairies for the period of **May 1-16, 2022**.

a. Pacific Northwest (Idaho, Oregon, Washington) – The majority of Pacific Northwest reverse trajectories have passed over south-central Alberta and western Saskatchewan (link to view Fig. 2).

b. Mexico and southwest USA (Texas, California) – Since April 1, reverse trajectories were reported for Manitoba (Portage, Selkirk, Brandon, Carman, Russell) and eastern Saskatchewan (Gainsborough, Grenfell) (link to view Fig. 3).

c. Oklahoma and Texas – Since April 1, reverse trajectories were reported for Manitoba and eastern Saskatchewan (link to view Fig. 4).

2. FORWARD TRAJECTORIES (FT)
The following map presents the total number of dates (since April 1, 2022) with forward trajectories (originating from Mexico and USA) predicted to cross the Canadian prairies (Fig. 5). Results indicate that the greatest number of forward trajectories entering Canada originated from the Pacific Northwest (Idaho, Oregon, Washington).

Figure 5. Total number of dates with forward trajectories, originating from various regions of the United States and Mexico, crossing the prairies between **April 1 and May 16, 2022**.

Weekly Wind Trajectory Report for June 28

Access background information for how and why wind trajectories are monitored in this post.

1. REVERSE TRAJECTORIES (RT)
Since June 16, 2021, a decreasing number of reverse trajectories have moved north from the Pacific Northwest (Idaho, Oregon and Washington), Texas, Oklahoma, Kansas and Nebraska (Fig. 1). Though these US regions can be a source of diamondback moths (DBM), the ECCC models predict air movement, not actual occurrence of diamondback moths. Fields (and DBM traps) should be monitored for DBM adults and larvae.

Figure 1. The average number (based on a 5 day running average) of reverse trajectories that have crossed the prairies for the period of May 28 – June 28, 2021.

a. Pacific Northwest (Idaho, Oregon, Washington) – This week (June 22-28, 2021) there were 3 trajectories that crossed Alberta, Manitoba and Saskatchewan that originated in the Pacific Northwest.

b. Mexico and southwest USA (Texas, California) – This week (June 22-28, 2021) there were 0 trajectories that originated in Mexico or the southwest USA that crossed the prairies.

c. Oklahoma and Texas – This week (June 22-28, 2021) there were 0 trajectories originating in Oklahoma or Texas that passed over the prairies.

d. Kansas and Nebraska – This week (June 22-28, 2021) there were 0 trajectories that originated in Kansas or Nebraska that passed over the prairies.

2. FORWARD TRAJECTORIES (FT)
a. Since June 9, 2021 there has been a steady decrease in the number of forward trajectories that are predicted to cross the prairies (Fig. 2). The dates on the graph report when the trajectories originated in the USA (blue bars). These trajectories generally require 3-5 days to enter the prairies (red line).

Figure 2. The average number (based on a 5 day running average) of forward trajectories that were predicted to cross the prairies for the period of May 28-June 28, 2021.

Weekly Wind Trajectory Report for June 15

Access background information for how and why wind trajectories are monitored in this post.

1. REVERSE TRAJECTORIES (RT)
Similar to last week, this week there were an increasing number of reverse trajectories moving north from the Pacific Northwest (Idaho, Oregon and Washington) (Fig. 1). Though this US region can be a source of diamondback moths (DBM), the ECCC models predict air movement, not actual occurrence of diamondback moths. Fields (and DBM traps) should be monitored for DBM adults and larvae.

Figure 1. The average number (based on a 5 day running average) of reverse trajectories that have crossed the prairies for the period of May 15 – June 15, 2021.

a. Pacific Northwest (Idaho, Oregon, Washington) – This week (June 11-15, 2021) there were 109 trajectories (versus 106 last week) that crossed Alberta, Manitoba and Saskatchewan (Fig. 2).

Figure 2. Total number of dates with reverse trajectories originating over the Pacific Northwest (Idaho, Oregon, and Washington) and have crossed the prairies between March 24 and June 15, 2021.

b. Mexico and southwest USA (Texas, California) – Compared to previous years, there has been a noticeable increase in number of trajectories from the southern US. The majority of these trajectories have crossed Manitoba and eastern Saskatchewan (Fig. 3). This week (June 11-15, 2021) there have been 11 trajectories (10 last week) that originated in Mexico or the southwest USA that have crossed the prairies.

Figure 3. The total number of dates with reverse trajectories originating over Mexico, California and Texas and have crossed the prairies between March 24 and June 15, 2021.

c. Oklahoma and Texas – The majority of these trajectories passed over Manitoba and eastern Saskatchewan (Fig. 4). This week (June 11-15, 2021) there were 18 trajectories (13 last week) originating in Oklahoma or Texas that passed over the prairies.

Figure 4. The total number of dates with reverse trajectories originating over Oklahoma and Texas and have crossed the prairies between March 24 and June 15, 2021.

d. Kansas and Nebraska – This week (June 11-15, 2021) there were 20 trajectories (19 last week) that originated in Kansas or Nebraska that passed over the prairies (Fig. 5).

Figure 5. The total number of dates with reverse trajectories originating over Kansas and Nebraska and have crossed the prairies between March 24 and June 15, 2021.

2. FORWARD TRAJECTORIES (FT)
a. This week there was a decrease in the number of forward trajectories predicted to cross the prairies (Fig. 6). The dates on the graph report when the trajectories originated in the USA (blue bars). These trajectories generally require 3-5 days to enter the prairies (red line). The data suggests that there will be increased potential for introduction of DBM to the prairies.

Figure 6. The average number (based on a 5 day running average) of forward trajectories that were predicted to cross the prairies for the period of May 15-June 15, 2021.

Weekly Wind Trajectory Report for June 10

Access background information for how and why wind trajectories are monitored in this post.

1. REVERSE TRAJECTORIES (RT)
This past week (in particular June 9 and 10) there were an increasing number of reverse trajectories moving north from the Pacific Northwest (Idaho, Oregon and Washington), Texas, Oklahoma, Kansas and Nebraska (Fig. 1). Though these US regions can be a source of diamondback moths (DBM), the ECCC models predict air movement, not actual occurrence of diamondback moths. Fields (and DBM traps) should be monitored for DBM adults and larvae.

a. Pacific Northwest (Idaho, Oregon, Washington) – This week there have been 106 trajectories (53 last week) that have crossed Alberta, Manitoba and Saskatchewan. This growing season, PNW trajectories have crossed all parts of the prairies (Fig. 2).

b. Mexico and southwest USA (Texas, California) – Compared to previous years, there has been a noticeable increase in the number of trajectories from the southern US. The majority of these trajectories have crossed Manitoba and eastern Saskatchewan (Fig. 3). This week there have been 10 trajectories (0 last week) that originated in Mexico or the southwest USA that have crossed the prairies (Fig. 3).

c. Oklahoma and Texas – This week there have been 13 trajectories (0 last week) originating in Oklahoma or Texas that have passed over the prairies (Fig. 4).

d. Kansas and Nebraska – This week there were 19 trajectories (versus 1 last week) that originated in Kansas or Nebraska that passed over the prairies (Fig. 5). Relative to the reverse trajectories associated with Oklahoma and Texas (Fig. 4), the trajectories from Kansas and Nebraska have crossed further into Alberta (Fig. 5).

2. FORWARD TRAJECTORIES (FT)
a. Continuing a trend that began last week, this week there was an increase in the number of forward trajectories predicted to cross the prairies (Fig. 6). The dates on the graph report when the trajectories originated in the USA (blue bars). These trajectories generally require 3-5 days to enter the prairies (red line). The data suggests that there will be increased potential for introduction of DBM to the prairies.

Weekly Wind Trajectory Report for June 3

Access background information for how and why wind trajectories are monitored in this post.

1. REVERSE TRAJECTORIES (RT)
This past week there were an increasing number of reverse trajectories moving north from the Pacific Northwest (Idaho, Oregon and Washington) (Fig. 1). Though this US region can be a source of diamondback moths, the ECCC models predict air movement, not actual occurrence of diamondback moths.

Figure 1. The average number (based on a 5 day running average) of reverse trajectories that have crossed the prairies for the period of May 15 – June 3 2021.

a. Pacific Northwest (Idaho, Oregon, Washington) – This week there were 53 trajectories (compared to 36 last week) that crossed Alberta, Manitoba and Saskatchewan. In previous years, the majority of Pacific Northwest reverse trajectories usually have been reported to pass over southern Alberta. However, tis growing season, PNW trajectories have crossed all parts of the prairies (Figs. 2 and 3).

Figure 2. Total number of reverse trajectories originating across Idaho, Oregon, and Washington and have crossed specific prairie locations between March 18 and June 3, 2021.

Figure 3. Total number of dates with reverse trajectories originating over the Pacific Northwest (Idaho, Oregon, and Washington) and have crossed the prairies between March 24 and June 3, 2021.

b. Mexico and southwest USA (Texas, California) – Compared to previous years, there has been a noticeable increase in the number of trajectories from the southern US. The majority of these trajectories have crossed Manitoba and eastern Saskatchewan (Fig. 4). This week there were no trajectories (compared to 54 last week) that originated in Mexico or the southwest USA that crossed the prairies (Fig. 5).

Figure 4. Total number of reverse trajectories originating across Mexico, California and Texas and have crossed specific prairie locations between March 18 and June 3, 2021.

Figure 5. The total number of dates with reverse trajectories originating over Mexico, California and Texas and have crossed the prairies between March 24 and June 3, 2021.

c. Oklahoma and Texas – The majority of these trajectories have passed over Manitoba and eastern Saskatchewan (Fig. 6). This week there were no trajectories (compared to 51 last week) originating in Oklahoma or Texas that passed over the prairies (Fig. 7).

Figure 6. Total number of reverse trajectories originating across Oklahoma and Texas and have crossed specific prairie locations between March 18 and June 3, 2021.

Figure 7. The total number of dates with reverse trajectories originating over Oklahoma and Texas and have crossed the prairies between March 24 and June 3, 2021.

d. Kansas and Nebraska – Similar to results for Oklahoma and Texas, the majority of these trajectories crossed Manitoba and eastern Saskatchewan (Fig. 8). This week there was one trajectory that originated in Kansas or Nebraska that passed over Carman, Manitoba (Fig. 9). Relative to the reverse trajectories associated with Oklahoma and Texas, the trajectories from Kansas and Nebraska have crossed further into Alberta (Fig. 9).

Figure 8. Total number of reverse trajectories originating across Kansas and Nebraska and have crossed specific prairie locations between March 18 and June 3, 2021.

Figure 9. The total number of dates with reverse trajectories originating over Kansas and Nebraska and have crossed the prairies between March 24 and June 3, 2021.

2. FORWARD TRAJECTORIES (FT)
a. Continuing a trend that began last week, this week there was a decrease in the number of forward trajectories that were predicted to cross the prairies (Fig. 10). The dates on the graph report when the trajectories originated in the USA (blue bars). These trajectories generally require 3-5 days to enter the prairies (red line). The data suggests that, compared to this week, there will be decreased potential for the introduction of DBM to the prairies.

Figure 10. The average number (based on a 5-day running average) of forward trajectories that were predicted to cross the prairies for the period of May 15-June 3, 2021.

Weekly Wind Trajectory Report for May 28

Access background information for how and why wind trajectories are monitored in this post.

1. REVERSE TRAJECTORIES (RT)
Since May 1, 2021 the majority of reverse trajectories that have crossed the prairies originated from the Pacific Northwest (Idaho, Oregon and Washington). For the past two weeks there have been an increasing number of reverse trajectories that moved north from Texas, Oklahoma, Kansas and Nebraska (Fig. 1). Compared to previous years, the number incoming trajectories (May) has increased. Though these US regions can be a source of diamondback moths, the ECCC models predict air movement, not actual occurrence of diamondback moths. It should also be noted that host plants of diamondback moth include all plants in the Brassicacea family, including cruciferous weeds and volunteer canola. These plants are suitable hosts until canola emerges.

Figure 1. The average number (based on a 5 day running average) of reverse trajectories that have crossed the prairies for
the period of May 1 – 27 2021.

a. Pacific Northwest (Idaho, Oregon, Washington) – This week there have been 36 trajectories (44 last week) that have crossed Alberta, Manitoba and Saskatchewan. In previous years, the majority of Pacific Northwest reverse trajectories usually have been reported to pass over southern Alberta. This growing season, PNW trajectories have crossed all parts of the prairies (Fig. 2). Compared to this time last year there has been a significant increase in the number of trajectories that have crossed Manitoba and eastern Saskatchewan.

Figure 2. Total number of dates with reverse trajectories originating over Pacific Northwest (Idaho, Oregon, and Washington) and
have crossed the prairies between March 24 and May 27, 2021.

b. Mexico and southwest USA (Texas, California) – Compared to previous years, there has been a noticeable increase in number of trajectories from the southern US. This week there have been 54 trajectories (15 last week) that originated in Mexico and the southwestern US that have crossed the prairies (Fig. 3).

c. Oklahoma and Texas – This week there have been 51 trajectories (16 last week) that have passed over Manitoba, Saskatchewan and eastern Alberta that originated in Oklahoma or Texas (Fig. 4).

d. Kansas and Nebraska – This week there have been 63 trajectories (35 last week) that originated in Kansas or Nebraska that have passed over the prairies (Fig. 5). Relative to the reverse trajectories associated with Oklahoma and Texas, the trajectories from Kansas and Nebraska have crossed further into Alberta.

2. FORWARD TRAJECTORIES (FT)
a. Forward trajectories, originating from Mexico and USA, have crossed a number of prairie locations since May 1, 2021. This week there has been a decrease in the number of trajectories that are predicted to cross the prairies (Fig. 6). The dates on the graph report when the trajectories originated in the USA (blue bars). These trajectories generally require 3-5 days to enter the prairies (red line). The data suggests that, compared to this week, there may be increased potential for the introduction of DBM to the prairies.

Figure 6. The average number (based on a 5-day running average) of forward trajectories that have crossed
the prairies for the period of May 1- 27, 2021.

Weekly Wind Trajectory Report for May 20

Access background information for how and why wind trajectories are monitored in this post.

1. REVERSE TRAJECTORIES (RT)
Since May 1, 2021 the majority of reverse trajectories that have crossed the prairies originated from the Pacific Northwest (Idaho, Oregon and Washington). This week there have been an increasing number of reverse trajectories that moved north from Texas, Oklahoma and Kansas and Nebraska (Fig. 1). Though these US regions can be a source of diamondback moths, the ECCC models predict air movement, not actual occurrence of diamondback moths. It should also be noted that host plants of diamondback moth include all plants in the Brassicacea family, including cruciferous weeds and volunteer canola. These plants are suitable hosts until canola emerges.

**Figure 1.** The average number (based on a 5 day running average) of reverse trajectories that have crossed the prairies for
the period of May 1- 20, 2021.

a. Pacific Northwest (Idaho, Oregon, Washington) – This week there have been 44 trajectories (27 last week) that have crossed Alberta, Manitoba, and Saskatchewan. The majority of Pacific Northwest reverse trajectories usually have been reported to pass over southern Alberta. This growing season, PNW trajectories have crossed all of the prairies (Fig. 2).

b. Mexico and southwest USA (Texas, California) – This week there have been 15 trajectories that originated in Mexico and the southwestern US that have crossed Manitoba and Saskatchewan.

c. Oklahoma and Texas – This week there have been 16 trajectories that have passed over Manitoba and Saskatchewan (Fig. 3) that originated in Oklahoma or Texas. These are the first trajectories, that originated over Oklahoma and Texas, to enter the prairies during the month of May.

**Figure 3**. The total number of dates with reverse trajectories originating over Oklahoma and Texas and have crossed the
prairies between March 24 and May 20, 2021.

d. Kansas and Nebraska – This week there have been 35 trajectories (8 last week) that originated in Kansas or Nebraska that have passed over Manitoba and Saskatchewan (Fig. 4).

**Figure 4.** The total number of dates with reverse trajectories originating over Kansas and Nebraska and have crossed the
prairies between March 24 and May 20, 2021.

2. FORWARD TRAJECTORIES (FT)
a. Forward trajectories, originating from Mexico and USA, have crossed a number of prairie locations since May 1, 2021. This week, there has been a steady increase in the number of trajectories that are predicted to cross the prairies (Fig. 5). The dates on the graph report when the trajectories originated in the USA (blue bars). These trajectories generally require 3-5 days to enter the prairies (red line). The data suggests that, compared to this week, there may be increased potential for the introduction of DBM to the prairies.

**Figure 5.** The average number (based on a 5 day running average) of forward trajectories that have crossed the
Canadian prairies for the period of May 1- 20, 2021.

The following map presents the total number of forward trajectories that have crossed the Canadian prairies (since March 24, 2021) (Fig. 6). Results indicate that the greatest number of forward trajectories entering Canada originated from the Pacific Northwest (Idaho, Oregon, Washington).

**Figure 6.** The total number of dates with forward trajectories, originating from various regions of the United States and
Mexico, crossed the prairies between March 24 and May 20, 2021.

Earlier in the week, an Alert related to wind trajectories assessed over May 18-19, 2021, was shared by the PPMN. It communicated the anticpated arrival of several air masses arriving across the Canadian prairies over the next few days that originated from multiple areas of USA. Remember, the current WEEKLY REPORT (above) summarizes daily data over a longer, more comprehensive period.

ALERT – Wind Trajectory Report for May 19

Access background information for how and why wind trajectories are monitored in this earlier post.

Alert: Yesterday and today ECCC models produced results that suggest a number of RT’s for prairie locations. Compared to previous dates, the ECCC model output predicts that trajectories are passing almost the entire prairie region over a very short period of time. The weather forecast may result in downward movement of DBM.

Details: There has been a significant increase in the number of trajectories, originating over a number of states in the USA, that have crossed the prairies (Fig. 1). These air currents may introduce diamondback moths to the prairies. ECCC trajectory models indicate that air trajectories, originating over the Pacific Northwest (Idaho, Oregon, Washington), have crossed Alberta, Saskatchewan and western Manitoba (Fig. 2). Trajectories originating over Texas and Oklahoma have passed over eastern Saskatchewan and Manitoba (Fig. 3). A third group of trajectories, originating across Kansas and Nebraska have also crossed eastern Saskatchewan and Manitoba (Fig. 4).

Though these US regions can be a source of diamondback moths, the ECCC models predict air movement, not actual occurrence of diamondback moths. It should also be noted that host plants of diamondback moth include all plants in the Brassicaceae family, including cruciferous weeds and volunteer canola. These plants are suitable hosts until canola emerges.

Action: The ECCC model output predicts that trajectories are passing almost the entire prairie region over a very short period of time. Areas highlighted in green in Figures 2, 3, and 4 of this alert may receive downward movement of DBM very shortly. The presence of any Brassicaceae plant will provide a host for incoming DBM so scout volunteers and emerging canola. If DBM were carried north on air currents it may take a few days for DBM to show up in traps.

**Figure 1**. Summary of the average number (5 day running average) of reverse trajectories that have crossed the Canadian prairies (May 1-19, 2021)

**Figure 2**. The green region indicates the potential for introduction of diamondback moths from the Pacific Northwest (Idaho, Oregon, and Washington) to the Canadian prairies (May 18-19, 2021).

**Figure 3**. The green region indicates the potential for introduction of diamondback moths from Texas and Oklahoma to
the Canadian prairies (May 18-19, 2021).

**Figure 4**. The green region indicates the potential for introduction of diamondback moths from Kansas and Nebraska to the Canadian prairies (May 18-19, 2021).

Potential of trajectories for monitoring insect movements

Agriculture and Agri-Food Canada (AAFC) and Environment and Climate Change Canada (ECCC) have been working together to study the potential of trajectories for monitoring insect movements since the late 1990s. Trajectory models are used to deliver an early-warning system for the origin and destination of migratory invasive species, such as diamondback moth. In addition, plant pathologists have shown that trajectories can assist with the prediction of plant disease infestations and are also beginning to utilize these same data. We receive two types of model output from ECCC: reverse trajectories and forward trajectories.

‘Reverse trajectories’ refer to air currents that are tracked back in time from specified Canadian locations over a five-day period prior to their arrival date. Of particular interest are those trajectories that, prior to their arrival in Canada, originated over northwestern and southern USA and Mexico, anywhere diamondback moth populations overwinter and adults are actively migrating. If diamondback adults are present in the air currents that originate from these southern locations, the moths may be deposited on the Prairies at sites along the trajectory, depending on the local weather conditions at the time that the trajectories pass over our area (e.g. rain showers, etc.). Reverse trajectories are the best available estimate of the ”true” 3D wind fields at a specific point. They are based on observations, satellite and radiosonde data.

‘Forward trajectories’ have a similar purpose; however, the modeling process begins at sites in USA & Mexico. The model output predicts the pathway of a trajectory. Again, of interest to us are the winds that eventually end up passing over the Prairies.

Access all the Historical Wind Trajectory Reports.

Weiss1, Vankosky1, Trudel2
1 Agriculture and Agri-Food Canada
2 Environment and Climate Change Canada

Weekly Wind Trajectory Report (released May 13)

Agriculture and Agri-Food Canada (AAFC) and Environment and Climate Change Canada (ECCC) have been working together to study the potential of trajectories for monitoring insect movements since the late 1990s. Trajectory models are used to deliver an early-warning system for the origin and destination of migratory invasive species, such as diamondback moth. Read a brief overview of this strategy plus the definitions and applications of both ‘Reverse’ and ‘Forward’ trajectories.

1. REVERSE TRAJECTORIES (RT)
Since May 1, 2021, the majority of reverse trajectories crossing the prairies originated from the Pacific Northwest (Idaho, Oregon and Washington). This week, an increasing number of reverse trajectories have been moving north from Kansas and Nebraska (Fig. 1).

Figure 1. The average number (based on a 5-day running average) of reverse trajectories (RTs) that have
crossed the prairies for the period of May 1-13, 2021.

a. Pacific Northwest (Idaho, Oregon, Washington) – The majority of Pacific Northwest reverse trajectories have been reported to pass over southern Alberta (Fig. 2).

Figure 2. Total number of dates with reverse trajectories originating over the Pacific Northwest (PNW including Idaho, Oregon, and Washington) that have crossed the prairies between March 24 and May 13, 2021.

b. Mexico and southwest USA (Texas, California) – Since last week there have not been any trajectories that originated in these areas that have crossed the prairies.

c. Oklahoma and Texas – Since last week there have not been any trajectories originating in Oklahoma or Texas that have crossed the prairies.

d. Kansas and Nebraska – This week reverse trajectories were reported for Alberta (Andrew, Sedgewick), Saskatchewan (Gainsborough, Grenfell, Kindersley, Regina, Yorkton) and Manitoba (Brandon) (Fig. 3).

Figure 3. The total number of dates with reverse trajectories originating over Kansas and Nebraska that have crossed the
prairies between March 24 and May 13, 2021.

2. FORWARD TRAJECTORIES (FT)
Forward trajectories, originating from Mexico and USA have crossed a number of prairie locations since May 1, 2021. Based on average totals (averaged across a five day period), the greatest number of forward trajectories were observed to originate between May 5 and 8 (blue bars) and entered the prairies between May 6-9 (Fig. 4).

Figure 4. The average number (based on a 5 day running average) of forward trajectories that have crossed the
prairies for the period of May 1- 13, 2021.

The following map presents the total number of dates (since March 24, 2021) with forward trajectories that have crossed the Canadian prairies (Fig. 5). Results indicate that the greatest number of forward trajectories entering Canada originated from the Pacific Northwest (Idaho, Oregon, Washington).

Figure 5. The total number of dates with forward trajectories, originating from various regions of the United States and Mexico, that crossed the prairies between March 24 and May 13, 2021.

Access a PDF version of the full WEEKLY report released May13, 2021.

Wind Trajectory Report for May 10

ECCC trajectory models indicate that air trajectories, originating over the Pacific Northwest (Idaho, Oregon, Washington), have crossed one Saskatchewan location (Unity) and a number of Alberta locations including Lethbridge, Beiseker, Olds, Provost, Vegreville, Andrew, Grande Prairie, Rycroft and Fort Vermillion.

Access this DAILY one-page report to learn more. Albertans and Saskatchewanians please take note!

Areas highlighted green in this alert may receive incoming winds from the Pacific Northwest of the USA very shortly! Remember, host plants of diamondback moth include all plants in the Brassicacea family, including cruciferous weeds and volunteer canola. These plants are suitable hosts until canola emerges.

ALERT – Wind Trajectory Report for May 7

Environment and Climate Change Canada (ECCC) trajectory models indicate that air trajectories, originating over the Pacific Northwest (Idaho, Oregon, Washington), have crossed a number of Alberta locations including Lethbridge, Beiseker, Olds, Manning, Rycroft, and Wanham.

Access this special one-page alert to learn more. Albertans please take note!

Action: Areas highlighted green in this alert may receive incoming winds from the Pacific Northwest of the USA very shortly so please deploy diamondback pheromone traps as soon as possible!

Weekly Wind Trajectory Report (released May 5)

Access a PDF version of the full report for May 5, 2021.

Predicted diamondback moth development

The Diamondback moth (DBM) model was run with a biofix of May 15, 2020. DBM densities generally increase with increasing numbers of generations. Figure 1 represents the model output for the 2020 growing season (as of August 17, 2020). The number of generations varies from two in western Alberta to four in southeastern Saskatchewan and most of Manitoba (Fig. 1). Next, the model was run with climate normal data to compare the 2020 growing season with an ‘average’ growing season (Fig. 2). The second map (climate normal) indicates that an average growing season results in two to three generations, with a fourth generation predicted to occur near Winnipeg (Fig. 2). These results indicate that there was an elevated DBM risk in 2020.

**Figure 1**. Using a biofix date of May 15, 2020, the projected number of diamondback moth (*Plutella xylostella*) generations across the Canadian prairies as of August 17, 2020.

**Figure 2**. Using a biofix date of May 15, 2020, the projected number of diamondback moth (*Plutella xylostella*) generations across the Canadian prairies as of August 17, 2020, using climate normal data.

The economic threshold for diamondback moth in canola at the advanced pod stage is 20 to 30 larvae/ 0.1 m² (approximately 2-3 larvae per plant). Economic thresholds for canola or mustard in the early flowering stage are not available. However, insecticide applications are likely required at larval densities of 10 to 15 larvae/ 0.1 m² (approximately 1-2 larvae per plant).

Monitoring to apply the economic threshold: Remove the plants in an area measuring 0.1 m² (about 12″ square). Beat them on to a clean surface and count the number of larvae (Fig. 3) dislodged from the plant. Repeat this procedure at least in five locations in the field to get an accurate count.

This image has an empty alt attribute; its file name is DBM_Larva_AAFC.jpg — **Figure 3**. Diamondback larva measuring ~8mm long.
Note brown head capsule and forked appearance of prolegs on posterior.

This image has an empty alt attribute; its file name is DBM_Pupa_AAFC-1.jpg — **Figure 4**. Diamondback moth pupa within silken cocoon.

This image has an empty alt attribute; its file name is DBM_adult_AAFC-1.png — **Figure 5**. Diamondback moth.

Biological and monitoring information for DBM is posted by Manitoba Agriculture, Saskatchewan Agriculture, and the Prairie Pest Monitoring Network.

More information about Diamondback moths can be found by accessing the pages from the “Field Crop and Forage Pests and their Natural Enemies in Western Canada: Identification and Field Guide“. View ONLY the Diamondback moth page but remember the guide is available as a free downloadable document as both an English-enhanced or French-enhanced version.

Predicted diamondback moth development

This week, the DBM model based on Harcourt (1954) was run with a biofix of May 15, 2020. Most of Alberta has had two generations. It is possible that three generations have been completed across Saskatchewan and southeastern Alberta where it has been warmer. Results indicate that a potential fourth generation may be occurring across southern Manitoba. DBM densities generally increase with increasing numbers of generations. Later maturing canola fields may be susceptible to damage resulting from larval feeding.

Monitoring:

Remove the plants in an area measuring 0.1 m² (about 12″ square). Beat them on to a clean surface and count the number of larvae (Fig. 2) dislodged from the plant. Repeat this procedure at least in five locations in the field to get an accurate count.

Economic threshold for diamondback moth in canola at the advanced pod stage is 20 to 30 larvae/ 0.1 m² (approximately 2-3 larvae per plant). Economic thresholds for canola or mustard in the early flowering stage are not available. However, insecticide applications are likely required at larval densities of 10 to 15 larvae/ 0.1 m² (approximately 1-2 larvae per plant).

Biological and monitoring information for DBM is posted by Manitoba Agriculture, Saskatchewan Agriculture, and the Prairie Pest Monitoring Network.

Predicted diamondback moth development

Based on Harcourt (1954) the DBM model was run with a biofix of May 15, 2020. Model runs (as of August 3, 2020) were conducted with weather data for 2020 (Fig. 1) and climate normals (long term average temperatures). The first map illustrates that potentially three generations have been completed across Manitoba and southeastern Saskatchewan (Fig. 1). Most of the prairies have had two generations (Fig. 1). The second map, showing results for climate normal data, indicates that prairie populations should have completed two generations (Fig. 2).

The charts provide location specific details regarding potential development at Winnipeg (Fig. 3) and Lacombe (Fig. 4). The first chart illustrates DBM development at Winnipeg. Results indicate that there is potential for a fourth generation of DBM to occur in southern Manitoba. Populations near Lacombe are predicted to be completing the second generation.

**Figure 3**. Predicted diamondback moth (*Plutella xylostella*) phenology at Saskatoon SK. Values are based on model simulations (April 1-August 3, 2020).

**Figure 4**. Predicted diamondback moth (*Plutella xylostella*) phenology at Lacombe AB. Values are based on model simulations (April 1-August 3, 2020).

Monitoring:

Remove the plants in an area measuring 0.1 m² (about 12″ square). Beat them on to a clean surface and count the number of larvae (Fig. 5) dislodged from the plant. Repeat this procedure at least in five locations in the field to get an accurate count.

Biological and monitoring information for DBM is posted by Manitoba Agriculture, Saskatchewan Agriculture, and the Prairie Pest Monitoring Network.

Diamondback moth

Monitoring: Remove the plants in an area measuring 0.1 m² (about 12″ square), beat them on to a clean surface and count the number of larvae (Fig. 1) dislodged from the plant. Repeat this procedure at least in five locations in the field to get an accurate count.

Biological and monitoring information for DBM is posted by Manitoba Agriculture, Saskatchewan Agriculture, and the Prairie Pest Monitoring Network.

Diamondback moth

Once diamondback moth is present in the area, it is important to monitor individual canola fields for larvae. Warm growing conditions can quickly translate into multiple generations in a very short period!

Wind Trajectory Updates – Completed for 2020 growing season as of Week 09 (released June 22, 2020).

Weekly Pheromone-baited Trapping Results – Early season detection of diamondback moth is improved through the use of pheromone-baited delta traps deployed in fields across the Canadian prairies. Click each province to access moth reporting numbers observed in Alberta, Saskatchewan and Manitoba as they become available. Check these sites to assess cumulative counts and relative risk in your geographic region.

Figure 1. Diamondback larva measuring ~8 mm long.Note brown head capsule and forked appearance of prolegs on posterior.

Figure 2. Diamondback moth pupa within silken cocoon.

Biological and monitoring information for DBM is posted by Manitoba Agriculture, Saskatchewan Agriculture, and the Prairie Pest Monitoring Network.

Wind trajectories

The entire list of 2020 Wind Trajectory Reports is available here.

→ Read the WEEKLY Wind Trajectory Report for Wk10 (released June 22, 2020).

Wind Trajectories

The entire list of 2020 Wind Trajectory Reports is available here.

→ Read the WEEKLY Wind Trajectory Report for Wk08 (released June 15, 2020).

Wind trajectories

The entire list of 2020 Wind Trajectory Reports is available here.

→ Read the WEEKLY Wind Trajectory Report for Wk07 (released June 8, 2020).

Wind trajectories

The entire list of 2020 Wind Trajectory Reports is available here.

→ Read the WEEKLY Wind Trajectory Report for Wk06 (released June 1, 2020).

Wind trajectories

The entire list of 2020 Wind Trajectory Reports is available here.

→ Read the WEEKLY Wind Trajectory Report for Wk05 (released May 25, 2020).

Wind trajectories

The entire list of 2020 Wind Trajectory Reports is available here.

→ Read the WEEKLY Wind Trajectory Report for Wk04 (released May 18, 2020).

→ Read the DAILY Wind Trjectory Reports for Wk04 (released May 20 and May 21).

Wind trajectories

Access the 2020 Wind Trajectory Reportsfor the first WEEKLY REPORT (11 May 2020).

New – Review the DAILY REPORT (released 15May2020).

Wind trajectories

Find the first WEEKLY report (available 11 May 2020).

Wind trajectories

Data not available this week.

Diamondback moth

Diamondback moth (Plutellidae: Plutella xylostella) – Once diamondback moth is present in the area, it is important to monitor individual canola fields for larvae. Warm growing conditions can quickly translate into multiple generations in a very short period!

Monitoring:

Remove the plants in an area measuring 0.1 m² (about 12″ square), beat them on to a clean surface and count the number of larvae (Fig. 1) dislodged from the plant. Repeat this procedure at least in five locations in the field to get an accurate count.

Biological and monitoring information for DBM is posted by Manitoba Agriculture, Saskatchewan Agriculture, and the Prairie Pest Monitoring Network.

Diamondback moth

Monitoring:

Biological and monitoring information for DBM is posted by Manitoba Agriculture, Saskatchewan Agriculture, and the Prairie Pest Monitoring Network.

Wind Trajectories

In a continuing effort to produce timely information, the wind trajectory reports are available in two forms:

DAILY REPORTS, as they can be generated, are accessible as a downloadable PDF file on this page.
WEEKLY REPORTS can be retrieved by clicking this hyperlink with the most recent version available here.

Wind Trajectories

In a continuing effort to produce timely information, the wind trajectory reports are available in two forms:

DAILY REPORTS, as they can be generated, are accessible as a downloadable PDF file on this page.
WEEKLY REPORTS can be retrieved by clicking this hyperlink with the most recent version available here.

Wind Trajectories

In a continuing effort to produce timely information, the wind trajectory reports are available in two forms:

DAILY REPORTS, as they can be generated, are accessible as a downloadable PDF file on this page.
WEEKLY REPORTS can be retrieved by clicking this hyperlink with the most recent version available here.

Wind Trajectories

In a continuing effort to produce timely information, the wind trajectory reports are available in two forms:

DAILY REPORTS, as they can be generated, are accessible as a downloadable PDF file on this page.
WEEKLY REPORTS can be retrieved by clicking this hyperlink with the most recent version available here.

Wind Trajectories

In a continuing effort to produce timely information, the wind trajectory reports are available in two forms:

DAILY REPORTS, as they can be generated, are accessible as a downloadable PDF file on this page.
WEEKLY REPORTS can be retrieved by clicking this hyperlink with the most recent version available here.

Wind Trajectories

In a continuing effort to produce timely information, the wind trajectory reports are available in two forms:

DAILY REPORTS, as they can be generated, are accessible as a downloadable PDF file on this page.
WEEKLY REPORTS can be retrieved by clicking this hyperlink with the most recent version available here.

Wind Trajectories

In a continuing effort to produce timely information, the wind trajectory reports are available in two forms:

DAILY REPORTS, as they can be generated, are accessible as a downloadable PDF file on this page.
WEEKLY REPORTS can be retrieved by clicking this hyperlink with the most recent version available here.

Wind Trajectories

In a continuing effort to produce timely information, the wind trajectory reports are available in two forms:

DAILY REPORTS, as they can be generated, are accessible as a downloadable PDF file on this page.
WEEKLY REPORTS can be retrieved by clicking this hyperlink with the most recent version available here.

Wind trajectories

Agriculture and Agri-Food Canada (AAFC) and Environment and Climate Change Canada (ECCC) have been working together to study the potential of trajectories for monitoring insect movements since the late 1990s. Trajectory models are used to deliver an early-warning system for the origin and destination of migratory invasive species, such as diamondback moth. In addition, plant pathologists have shown that trajectories can assist with the prediction of plant disease infestations and are also beginning to utilize these same data. We receive two types of model output from ECCC: reverse trajectories and forward trajectories.

‘Reverse trajectories’ (RT) refer to air currents that are tracked back in time from specified Canadian locations over a five-day period prior to their arrival date. Of particular interest are those trajectories that, prior to their arrival in Canada, originated over northwestern and southern USA and Mexico, anywhere diamondback moth populations overwinter and adults are actively migrating. If diamondback adults are present in the air currents that originate from these southern locations, the moths may be deposited on the Prairies at sites along the trajectory, depending on the local weather conditions at the time that the trajectories pass over our area (e.g. rain showers, etc.). Reverse trajectories are the best available estimate of the ”true” 3D wind fields at a specific point. They are based on observations, satellite and radiosonde data.

‘Forward trajectories’ (FT) have a similar purpose; however, the modelling process begins at sites in USA & Mexico. The model output predicts the pathway of a trajectory. Again, of interest to us are the winds that eventually end up passing over the Prairies.

Ross Weiss (AAFC), Meghan Vankosky (AAFC) and Serge Trudel (ECCC)

DATE: APRIL 30, 2019

1. Reverse trajectories (RT)

a. Pacific Northwest (PNW) – For the period of April 24-30 there have been 18 RTs (originating over ID, OR and WA) that have crossed over prairie locations. By comparison, for the period of April 17-23 there were 51 RT’s. The majority PNW RTs have been reported to pass over southern AB. Since March 23rd Lethbridge AB has reported the highest number of PNW RTs (n=22), Beiseker AB (n=15) and Olds AB (n=31).

b. Mexico and SW USA (TX, CA) – No trajectories, originating over Mexico or southwest USA have crossed the prairies for the period of April 24-30, 2019. Since March 23, 2019 there have been 5 reverse trajectories that originated over Mexico, CA and TX. All five occurred on April 7.

c. Texas and Oklahoma – No trajectories, originating over TX or OK have crossed the prairies for the period of April 24-30, 2019. Since March 23, 2019 there have been 18 reverse trajectories that have originated over OK and TX. Most of these trajectories have crossed eastern SK and MB.

2. Forward trajectories (FT) –

The following table reports the origin of forward trajectories predicted to cross the prairies over the next five days (Note: ‘InitialDate’ refers to when the forward trajectory crossed the source location. Trajectories are predicted to cross prairie locations within five days of the initial date).

In a continuing effort to produce timely information, wind trajectory reports will be available both DAILY and WEEKLY:

DAILY REPORTS, as they can be generated, will be put up as a downloadable PDF file on this page.
WEEKLY REPORTS can be retrieved by clicking this hyperlink.

Weather forecasts (7 day):

Winnipeg: https://weather.gc.ca/city/pages/mb-38_metric_e.html
Brandon: https://weather.gc.ca/city/pages/mb-52_metric_e.html
Saskatoon: https://weather.gc.ca/city/pages/sk-40_metric_e.html
Regina: https://weather.gc.ca/city/pages/sk-32_metric_e.html
Edmonton: https://weather.gc.ca/city/pages/ab-50_metric_e.html
Lethbridge: https://weather.gc.ca/city/pages/ab-30_metric_e.html
Grande Prairie: https://weather.gc.ca/city/pages/ab-31_metric_e.html

Wind Trajectories

Ross Weiss (AAFC), Meghan Vankosky (AAFC) and Serge Trudel (ECCC)

DATE: APRIL 24, 2019

Reverse trajectories (RT)

a. Pacific Northwest (PNW) – For the period of April 17-23, 2019, there have been 55 RT’s (originating over ID, OR and WA) that have crossed over prairie locations (Figs. 1 and 2). By comparison, for the period of April 10-16, 2019, there were 31 RT’s. The majority PNW RT’s have been reported to pass over southern AB. Since March 23rd, Lethbridge AB has reported the highest number of PNW RT’s (n=20), Beiseker AB (n=15) and Gainsborough SK (n=11).

b. Mexico and SW USA (TX, CA) – No trajectories, originating over Mexico or southwest USA have crossed the prairies for the period of April 17-23, 2019. Since March 23, 2019 there have been 5 reverse trajectories that originated over Mexico, CA and TX. All five occurred on April 7, 2019.

c. Texas and Oklahoma – No trajectories, originating over TX or OK have crossed the prairies for the period of April 17-23, 2019. Since March 23, 2019 there have been 18 reverse trajectories that have originated over OK and TX (Fig. 3). Most of these trajectories have crossed eastern SK and MB.

d. Nebraska and Kansas – No trajectories, originating over KS or NE have crossed the prairies for the period of April 17-23, 2019. Since March 23, 2019 there have been 18 reverse trajectories that have originated over KS and NE (Fig. 4).

In a continuing effort to produce timely information, wind trajectory reports will be available both DAILY and WEEKLY:

DAILY REPORTS, as they can be generated, will be put up as a downloadable PDF file on this page.
WEEKLY REPORTS can be retrieved by clicking this hyperlink.

Wind Trajectories

In a continuing effort to produce timely information, the wind trajectory reports will be available both DAILY and WEEKLY:

DAILY REPORTS, as they can be generated, will be put up as a downloadable PDF file on this page.
WEEKLY REPORTS will be included within the Weekly Update and can be retrieved by clicking this hyperlink.

2019 Risk and Forecast Maps for the Prairies

The 2019 Prairie-Wide Risk and Forecast Maps can be viewed and downloaded here.

Economically significant insect pests are monitored across the Canadian prairies each year, thanks to extensive networks of collaborators and cooperators. In 2018, that effort culminated in 5764 survey stops across Manitoba, Saskatchewan, Alberta and the BC Peace!

Here’s what’s included in the PDF file:

Average tempature, average precipitation, and modeled soil moisture for 2018.
A series of geospatial maps are included for each of the target species; the current map is followed by the previous 4 years.
For some species, the geospatial maps represent 2018 distributions used to infer risk in the coming 2019 growing season. Data is included for bertha armyworm, cabbage seedpod weevil, pea leaf weevil, wheat stem sawfly and diamondback moth.
For wheat midge and grasshoppers, the geospatial maps forecast or predict expected populations or risk for the 2019 growing season.

The historical Risk and Forecast Maps (2015-2019) are available for review.

These maps help the agricultural industry prepare to manage insect pests across the prairies and helps growers make crop choices and anticipate scouting priorities within their growing region. From May to July, the Weekly Updates will provide in-season updates, predictive model outputs plus scouting tips and links to relevant information.

Thank you to the many people who monitor each growing season!

Wind Trajectories

Ross Weiss (AAFC), Meghan Vankosky (AAFC) and Serge Trudel (ECCC)

DATE: APRIL 8, 2019

1. Reverse trajectories (RT):
a. Pacific Northwest (PNW) – For the period of April 2-8 there have been 69 RT’s (originating over the PNW) that have crossed over prairie locations. Since March 23rd Lethbridge has reported the highest number of PNW RT’s (n=9), followed by Olds AB, Beiseker AB and Dauphin MB (n=6).

List of PNW Reverse trajectories that have crossed the prairies (Since March 23, 2019):

b. Mexico and SW USA (SW) – On April 7 the first Southwestern USA and Mexico RT’s crossed the prairies. These reverse trajectories originated over TX and CA.

The following maps present two examples of April 7, 2019 RT’s. The first map indicates that the RT crossing Tisdale originated across southern TX. The second map shows that two RT’s crossed over Regina. The red line indicates that this RT originated over southern TX. A second RT originated across central CA.

Tisdale SK, April 7, 2019

Regina SK, April 7, 2019

2. Forward trajectories (FT) –

The following table reports the origin of forward trajectories predicted to cross the prairies over the next five days. Forward trajectories, originating over Santa Maria, CA are predicted to pass over SK and MB in the next five days.

The following is a list of 2018 Posts – click to review:

Abundant parasitoids in canola – Week 10
Alfalfa weevil – Week 6

Cabbage seedpod weevil – Week 12
Cabbage root maggot – Week 11
Cereal aphid manager (CAM) – Week 2
Cereal leaf beetle larvae request – Week 8
Crop protection guides – Week 2
Cutworms – Week 4

Diamondback moth – Week 7
Download the field guide – Week 10

Field heroes – Week 8
Flea beetles – Week 4

Monarch migration – Week 8

PMRA Pesticide Label Mobile App – Week 4

Scouting charts (canola and flax) – Week 3

Ticks and Lyme Disease – Week 4

Weather radar – Week 3
Wheat midge – Week 12

White grubs in fields – Week 8

Wind trajectories – Week 6
Wireworm distribution maps – Week 6

The following is a list of 2018 Posts – click to review:

Abundant parasitoids in canola – Week 10
Alfalfa weevil – Week 6

Cabbage seedpod weevil – Week 8
Cabbage root maggot – Week 11
Cereal aphid manager (CAM) – Week 2
Cereal leaf beetle – Week 5
Cereal leaf beetle larvae request – Week 8
Crop protection guides – Week 2
Crop reports – Week 8
Cutworms – Week 4

Diamondback moth – Week 7
Download the field guide – Week 10

Field heroes – Week 8
Flea beetles – Week 4

Monarch migration – Week 8

Pea leaf weevil – Week 8
PMRA Pesticide Label Mobile App – Week 4

Scouting charts (canola and flax) – Week 3

Ticks and Lyme Disease – Week 4

Weather radar – Week 3
White grubs in fields – Week 8
Wind trajectories – Week 6
Wireworm distribution maps – Week 6

The following is a list of 2018 Posts – click to review:

Abundant parasitoids in canola – Week 10

Alfalfa weevil – Week 6

Cabbage seedpod weevil – Week 8
Cereal aphid manager (CAM) – Week 2
Cereal leaf beetle – Week 5
Cereal leaf beetle larvae request – Week 8
Crop protection guides – Week 2
Crop reports – Week 8
Cutworms – Week 4

Diamondback moth – Week 7
Download the field guide – Week 10

Field heroes – Week 8
Flea beetles – Week 4

Monarch migration – Week 8

Pea leaf weevil – Week 8
PMRA Pesticide Label Mobile App – Week 4

Scouting charts (canola and flax) – Week 3

Ticks and Lyme Disease – Week 4

Weather radar – Week 3
Wind trajectories – Week 6
Wireworm distribution maps – Week 6
White grubs in fields – Week 8

Abundant parastioids in canola!

The cabbage seedpod weevil is a chronic pest of canola in southern Alberta and south western Saskatchewan; it has recently reached Manitoba as well. The pest is managed with insecticides, which are sprayed at early flower. This year, in some canola fields around Lethbridge AB, an abundant parasitoid wasp was noticed at the time when fields may be sprayed. The wasp was identified as Diolcogaster claritibia (Fig. 1; thanks to Vincent Hervet and Jose Fernandez for confirming identification).

The wasp is a parasitoid that attacks diamondback moth larvae and recently abundant in some fields in 2017. In some of the fields sampled, as many parasitoids as cabbage seedpod weevil (i.e., nearly one per sweep) were observed. In the fields sampled (i.e., around 10), cabbage seedpod weevils were below thresholds on average, though some spots may have been close to the threshold of 2-3 weevils per sweep.

The above observation emphasizes the value of beneficial arthropods like Diolcogaster claritibia. It is important to recognize that foliar applications of insecticides kill beneficial insects like this small wasp (about 2 mm) which attacks and helps regulate pest populations of diamondback moth or other Lepidoptera, including cutworms and cabbage worms. Thus, think beneficials before you spray!

Figure 1. *Diolcagaster claritibia* adult measuring ~2mm in length (Photo credit J. Fernandez, AAFC-Ottawa).

Learn more about beneficials by accessing Field Heroes and all the Blog’s Parasitoid posts.

The following is a list of 2018 Posts – click to review:

Alfalfa weevil – Week 6

Diamondback moth – Week 7

Field heroes – Week 8
Flea beetles – Week 4

Monarch migration – Week 8

Pea leaf weevil – Week 8
PMRA Pesticide Label Mobile App – Week 4

Scouting charts (canola and flax) – Week 3

Ticks and Lyme Disease – Week 4

Weather radar – Week 3
West nile virus – Week 8
Wind trajectories – Week 6
Wireworm distribution maps – Week 6
White grubs in fields – Week 8

Diamondback moth

Monitoring:

Across the prairies, provincial staffs coordinate diamondback pheromone trapping during the growing season. Every spring, the early arrival of diamondback moths (Fig. 3) is monitored through the tracking of high level air masses that originate from the south of North America and arrive across the Canadian prairies. Additionally, pheromone traps are deployed to intercept the initial moths. Cumulative male moth counts occurring over a 6-7 week period of trapping are used to estimate relative risk for the growing season. Vast networks of cooperators across Manitoba, Saskatchewan, Alberta, and the BC Peace work with their provincial entomologists to generate the following in-season results:

● Counts are summarized by Saskatchewan Agriculture (updated June 15, 2018, by J. Tansey):

● Manitoba Agriculture generally reports low DBM counts so far but review the specifics by region within the latest Insect and Disease Update (June 6, 2018).

● Alberta Agriculture and Forestry has a live 2018 map reporting Diamondback moth pheromone trap interceptions. A copy of the map (retrieved June 21, 2018) is below for reference.

Biological and monitoring information for DBM is posted by Manitoba Agriculture, Saskatchewan Agriculture, Alberta Agriculture and Forestry, and the Prairie Pest Monitoring Network.

More information about Diamondback moths can be found by accessing the pages from the new “Field Crop and Forage Pests and their Natural Enemies in Western Canada: Identification and Field Guide”. View ONLY the Diamondback moth page but remember the guide is available as a free downloadable document as both an English-enhanced or French-enhanced version.

Wind trajectories

Background: Agriculture and Agri-Food Canada (AAFC) and Environment and Climate Change Canada (ECCC) have been working together to study the potential of trajectories to deliver an early-warning system for the origin and destination of migratory invasive agricultural pests.

We receive two types of model output from ECCC: reverse trajectories (RT) and forward trajectories (FT):

(i) ‘Reverse trajectories’ (RT) refer to air currents that are tracked back in time from specified Canadian locations over a five-day period prior to their arrival date.

(ii) ‘Forward trajectories’ (FT) have a similar purpose; however, the modelling process begins at sites in USA and Mexico. The model output predicts the pathway of a trajectory. Again, of interest are the winds that eventually end up passing over the Prairies.

Current Data

Since April 1. 2018, the majority of Pacific Northwest (PNW) air currents have crossed over southern AB (Fig. 1). The cumulative number of wind dispersal events for June 1 – 11, 2018 (181) is greater than the long term (2007 – 2017) average (98).

Since April 1, the majority of air currents from southwest USA and Mexico have crossed over eastern SK and western MB (Fig. 2). So far there have been 18 RT’s (June 1 – 11, 2018) and compares with 2017 (3) and the long term average (24).

Weather forecasts (7 day):

Winnipeg: https://weather.gc.ca/city/pages/mb-38_metric_e.html
Brandon: https://weather.gc.ca/city/pages/mb-52_metric_e.html
Saskatoon: https://weather.gc.ca/city/pages/sk-40_metric_e.html
Regina: https://weather.gc.ca/city/pages/sk-32_metric_e.html
Edmonton: https://weather.gc.ca/city/pages/ab-50_metric_e.html
Lethbridge: https://weather.gc.ca/city/pages/ab-30_metric_e.html
Grande Prairie: https://weather.gc.ca/city/pages/ab-31_metric_e.html

Wind trajectories

We receive two types of model output from ECCC: reverse trajectories (RT) and forward trajectories (FT):

(i) ‘Reverse trajectories’ (RT) refer to air currents that are tracked back in time from specified Canadian locations over a five-day period prior to their arrival date.

Current Data
The number of Reverse Trajectories (RTs), crossing the prairies in May 2018, was lower than the long term average (2007 – 2017). The total number of incoming trajectories (sum of Pacific Northwest and southwest USA/Mexico) for 2018 was less than similar values for 2017 and 2007 – 2017. Based on RTs by region, the number of RTs from the Pacific Northwest (PNW) was less than 2007 – 2017 and 2017. To date, the RTs originating in the southwest USA/Mexico in 2018, have been greater in number than in 2017 and less than the long term average (Fig. 1).

Weather forecasts (7 day):

Winnipeg: https://weather.gc.ca/city/pages/mb-38_metric_e.html Brandon: https://weather.gc.ca/city/pages/mb-52_metric_e.html Saskatoon: https://weather.gc.ca/city/pages/sk-40_metric_e.html Regina: https://weather.gc.ca/city/pages/sk-32_metric_e.html Edmonton: https://weather.gc.ca/city/pages/ab-50_metric_e.html Lethbridge: https://weather.gc.ca/city/pages/ab-30_metric_e.html Grande Prairie: https://weather.gc.ca/city/pages/ab-31_metric_e.html

Wind trajectories

We receive two types of model output from ECCC: reverse trajectories (RT) and forward trajectories (FT):

(i) ‘Reverse trajectories’ (RT) refer to air currents that are tracked back in time from specified Canadian locations over a five-day period prior to their arrival date.

Current Data

Since May 21, 2018, the number of incoming trajectories (RTs) crossing the prairies has increased, particularly from California, Texas and Mexico (Fig. 1). The increased number of reverse trajectories could result in increased introductions of insects into the prairies.

Weather forecasts (7 day):

Wind trajectories

Background. Agriculture and Agri-Food Canada (AAFC) and Environment and Climate Change Canada (ECCC) have been working together to study the potential of trajectories to deliver an early-warning system for the origin and destination of migratory invasive agricultural pests.

We receive two types of model output from ECCC: reverse trajectories (RT) and forward trajectories (FT):

(i) ‘Reverse trajectories’ (RT) refer to air currents that are tracked back in time from specified Canadian locations over a five-day period prior to their arrival date.

(ii) ‘Forward trajectories’ (FT) have a similar purpose; however, the modelling process begins at sites in USA and Mexico. The model output predicts the pathway of a trajectory. Again, of interest are the winds that eventually end up passing over the Prairies.

Current Data

Pacific Northwest (PNW) – The total number of RT’s from the Pacific Northwest of the United States, for the period between May 1 – 22, 2018, was n=67. This was significantly less than in 2017 (n=226), as well as the long term average (n=166) (Fig. 1).


Figure 1. Daily total number of reverse trajectories originating over the Pacific Northwest of the United States that have entered the prairies (May 1-22, 2018).

Weather forecasts (7 day):

Winnipeg: https://weather.gc.ca/city/pages/mb-38_metric_e.html

Brandon: https://weather.gc.ca/city/pages/mb-52_metric_e.html

Saskatoon: https://weather.gc.ca/city/pages/sk-40_metric_e.html

Regina: https://weather.gc.ca/city/pages/sk-32_metric_e.html

Edmonton: https://weather.gc.ca/city/pages/ab-50_metric_e.html

Lethbridge: https://weather.gc.ca/city/pages/ab-30_metric_e.html

Grande Prairie: https://weather.gc.ca/city/pages/ab-31_metric_e.html

Wind trajectories

Background. Agriculture and Agri-Food Canada (AAFC) and Environment and Climate Change Canada (ECCC) have been working together to study the potential of trajectories for monitoring insect movements since the late 1990’s. Trajectory models are used to deliver an early-warning system for the origin and destination of migratory invasive species, such as diamondback moth. In addition, plant pathologists have shown that trajectories can assist with the prediction of plant disease infestations and are also beginning to utilize these same data.

We receive two types of model output from ECCC: reverse trajectories (RT) and forward trajectories (FT):
(i) Reverse trajectories refer to air currents that are tracked back in time from specified Canadian locations over a five-day period prior to their arrival date. Of particular interest are those trajectories that, prior to their arrival in Canada, originated over northwestern and southern USA and Mexico, anywhere diamondback moth populations overwinter and adults are actively migrating. If diamondback adults are present in the air currents that originate from these southern locations, the moths may be deposited on the Prairies at sites along the trajectory, depending on the local weather conditions at the time that the trajectories pass over our area (e.g. rain showers, etc.). RTs are the best available estimate of 3D wind fields at a specific point. They are based on observations, satellite and radiosonde data.

(ii) Forward trajectories have a similar purpose; however, the modelling process begins at sites in USA and Mexico. The model output predicts the pathway of a trajectory. Again, of interest to us are the winds that eventually end up passing over the Prairies.

Current Data

Pacific Northwest (PNW) – The number of RTs, predicted to cross the prairies, has increased over the past week (Fig. 1). Though there has been an increase, results for May 1-14 predicted that 38 PNW reverse trajectories (RT) have crossed the prairies. This total is less than the average number 107 (based on 2007-2017) and well below last year’s results (155).

Figure 1. Daily total of reverse trajectories (RT) originating over the Pacific Northwest that
have entered the prairies during April 2018.

Weather forecasts (7 day):

Winnipeg: https://weather.gc.ca/city/pages/mb-38_metric_e.html
Brandon: https://weather.gc.ca/city/pages/mb-52_metric_e.html
Saskatoon: https://weather.gc.ca/city/pages/sk-40_metric_e.html
Regina: https://weather.gc.ca/city/pages/sk-32_metric_e.html
Edmonton: https://weather.gc.ca/city/pages/ab-50_metric_e.html
Lethbridge: https://weather.gc.ca/city/pages/ab-30_metric_e.html
Grande Prairie: https://weather.gc.ca/city/pages/ab-31_metric_e.html

Wind trajectories

Background. Agriculture and Agri-Food Canada (AAFC) and Environment and Climate Change Canada (ECCC) have been working together to study the potential of trajectories for monitoring insect movements since the late 1990’s. Trajectory models are used to deliver an early-warning system for the origin and destination of migratory invasive species, such as diamondback moth. In addition, plant pathologists have shown that trajectories can assist with the prediction of plant disease infestations and are also beginning to utilize these same data.

We receive two types of model output from ECCC: reverse trajectories (RT) and forward trajectories (FT):
(i) Reverse trajectories refer to air currents that are tracked back in time from specified Canadian locations over a five-day period prior to their arrival date. Of particular interest are those trajectories that, prior to their arrival in Canada, originated over northwestern and southern USA and Mexico, anywhere diamondback moth populations overwinter and adults are actively migrating. If diamondback adults are present in the air currents that originate from these southern locations, the moths may be deposited on the Prairies at sites along the trajectory, depending on the local weather conditions at the time that the trajectories pass over our area (e.g. rain showers, etc.). RTs are the best available estimate of 3D wind fields at a specific point. They are based on observations, satellite and radiosonde data.

(ii) Forward trajectories have a similar purpose; however, the modelling process begins at sites in USA and Mexico. The model output predicts the pathway of a trajectory. Again, of interest to us are the winds that eventually end up passing over the Prairies.

Current Data

Pacific Northwest (PNW) – The number of RTs predicted to cross the prairies from the PNW, has increased over the last few days. Model runs for May 7th predicted that seven RTs will cross over AB and SK in the next 24 hours from the PNW. Based on results for April, there have been fewer RTs in 2018 than 2017. The number of RTs were greatest across southern AB (Fig. 1). The majority of these crossed the prairies in mid-April (Fig. 2).

Figure 1. Total number of reverse trajectories, originating over the US PNW, that
has entered the prairies during April, 2018.

Figure 2. Daily total number of reverse trajectories, originating over the US PNW, that
have entered the prairies during April, 2018.

Weather forecasts (7 day):

Winnipeg: https://weather.gc.ca/city/pages/mb-38_metric_e.html
Brandon: https://weather.gc.ca/city/pages/mb-52_metric_e.html
Saskatoon: https://weather.gc.ca/city/pages/sk-40_metric_e.html
Regina: https://weather.gc.ca/city/pages/sk-32_metric_e.html
Edmonton: https://weather.gc.ca/city/pages/ab-50_metric_e.html
Lethbridge: https://weather.gc.ca/city/pages/ab-30_metric_e.html
Grande Prairie: https://weather.gc.ca/city/pages/ab-31_metric_e.html

Weekly Update – Diamondback moth

Diamondback moth (Plutellidae: Plutella xylostella) – Based on Harcourt (1954), this week the DBM model was run with a biofix date of May 21. The following map illustrates that potentially three generations (after the migratory population) may have been completed across most of the prairies.

REMINDER – Once diamondback moth is present in the area, it is important to monitor individual canola fields for larvae. Remove the plants in an area measuring 0.1 m² (about 12″ square), beat them on to a clean surface and count the number of larvae (Fig. 1) dislodged from the plant. Repeat this procedure at least in five locations in the field to get an accurate count. The economic threshold for diamondback moth in canola at the advanced pod stage is 20 to 30 larvae/ 0.1 m² (approximately 2-3 larvae per plant). Economic thresholds for canola or mustard in the early flowering stage are not available. However, insecticide applications are likely required at larval densities of 10 to 15 larvae/ 0.1 m² (approximately 1-2 larvae per plant).

Figure 1. Diamondback larva measuring ~8mm long.
Note brown head capsule and forked appearance of prolegs on posterior.

Figure 2. Diamondback moth pupa within silken cocoon.

Biological and monitoring information for DBM is posted by Manitoba Agriculture, Food and Rural Development, Saskatchewan Agriculture, Alberta Agriculture and Forestry, and the Prairie Pest Monitoring Network.

More information about Diamondback moths can be found by accessing the pages from the new “Field Crop and Forage Pests and their Natural Enemies in Western Canada: Identification and Field Guide”. View ONLY the Diamondback moth page but remember the guide is available as a free downloadable document as both an English-enhanced or French-enhanced version.

Figure 3. Diamondback moth.

Across the prairies, provincial staff coordinate diamondback pheromone trapping during the growing season:
● Low numbers of moths have been reported across Saskatchewan for the 2017 pheromone monitoring.
● Manitoba Agriculture and Rural Initiatives posted low DBM counts which can be reviewed here.
● Alberta Agriculture and Forestry has a live 2017 map reporting Diamondback moth pheromone trap interceptions. A copy of the map (retrieved July 20, 2017) is below for reference.

Weekly Update – Diamondback moth

Diamondback moth (Plutellidae: Plutella xylostella) – Last week, biofix dates were used to predict the number of generations of DBM as of July 24, 2017. That data predicted the completion of two generations of DBM across the Canadian prairies. The number of generations, combined with the recent heat, has resulted in densities of DBM above threshold in some fields this week! In-field scouting is critical and necessary to protect developing pods since DBM larvae will feed on the exterior which can render pods prone to shattering even in high temperatures and high winds or during swathing and direct-harvesting.

REMINDER – Once diamondback moth is present in the area, it is important to monitor individual canola fields for larvae. Remove the plants in an area measuring 0.1 m² (about 12″ square), beat them on to a clean surface and count the number of larvae (Fig. 4) dislodged from the plant. Repeat this procedure at least in five locations in the field to get an accurate count. The economic threshold for diamondback moth in canola at the advanced pod stage is 20 to 30 larvae/ 0.1 m² (approximately 2-3 larvae per plant). Economic thresholds for canola or mustard in the early flowering stage are not available. However, insecticide applications are likely required at larval densities of 10 to 15 larvae/ 0.1 m² (approximately 1-2 larvae per plant).

Figure 4. Diamondback larva measuring ~8mm long.
Note brown head capsule and forked appearance of prolegs on posterior.

Figure 5. Diamondback moth pupa within silken cocoon.

Figure 6. Diamondback moth.

Weekly Update – Diamondback moth

Diamondback moth (Plutellidae: Plutella xylostella) – Throughout April and May, both forward and backward wind trajectory data was compiled weekly to identify potential DBM arrival events from southerly source areas including Mexico and southwest USA or the Pacific Northwest. This week, two biofix dates were selected as “starting points” used to apply the DBM model based on Harcourt (1954). By selecting and presenting mapped model outputs for both a biofix date of May 1 (Fig. 1) AND May 21 (Fig. 3), the predicted number of generations of DBM can be estimated across the Canadian prairies as of July 24, 2017. The following maps indicate that potentially two generations have been completed across most of the prairies for both biofix dates (Fig. 1 and 3).

Using Biofix of May 1 – Based on the biofix date of May 1, 2017, the model predicts two generations of DBM (e.g., areas highlighted in yellow) whereas southern Alberta populations are potentially in the third generation (Fig. 1). The second map (Fig. 2), showing predicted results for Long Term Normal (LTN) data, indicates that populations in southern Alberta and the Peace River region are ahead of normal development (based on May 1 introductions).

Figure 1. Predicted number of generations of Diamondback moth based on a biofix date of May 1, 2017.

Figure 2. Predicted number of generations of Diamondback moth based on a biofix date of
May 1, 2017, but using Long Term Normal (LTN) data.

Using Biofix of May 21 – In the following scenario using biofix date of May 21, 2017 (Fig. 3), the number of generations of DBM are marginally behind the early May introduction presented above in Figure 1.

Figure 3. Predicted number of generations of Diamondback moth based on a biofix date of May 21, 2017.

REMINDER – Once diamondback moth is present in the area, it is important to monitor individual canola fields for larvae. Remove the plants in an area measuring 0.1 m² (about 12″ square), beat them on to a clean surface and count the number of larvae (Fig. 4) dislodged from the plant. Repeat this procedure at least in five locations in the field to get an accurate count. The economic threshold for diamondback moth in canola at the advanced pod stage is 20 to 30 larvae/ 0.1 m² (approximately 2-3 larvae per plant). Economic thresholds for canola or mustard in the early flowering stage are not available. However, insecticide applications are likely required at larval densities of 10 to 15 larvae/ 0.1 m² (approximately 1-2 larvae per plant).

Figure 4. Diamondback larva measuring ~8mm long.
Note brown head capsule and forked appearance of prolegs on posterior.

Figure 5. Diamondback moth pupa within silken cocoon.

Figure 6. Diamondback moth.

Across the prairies, provincial staff coordinate diamondback pheromone trapping during the growing season:
● Low numbers of moths have been reported across Saskatchewan for the 2017 pheromone monitoring.
● Manitoba Agriculture and Rural Initiatives posted low DBM counts which can be reviewed here.
● Alberta Agriculture and Forestry has a live 2016 map reporting Diamondback moth pheromone trap interceptions. A copy of the map (retrieved July 20, 2017) is below for reference.

Weekly Update – Diamondback moth

Diamondback moth (Plutellidae: Plutella xylostella) – Once the diamondback moth is present in the area, it is important to monitor individual canola fields for larvae.

Remove the plants in an area measuring 0.1 m² (about 12″ square), beat them on to a clean surface and count the number of larvae (Fig. 1) dislodged from the plant. Repeat this procedure at least in five locations in the field to get an accurate count.

Figure 1. Diamondback larva measuring ~8mm long.
Note brown head capsule and forked appearance of prolegs on posterior.

Figure 2. Diamondback moth pupa within silken cocoon.

Figure 3. Diamondback moth.

Across the prairies, provincial staff coordinate diamondback pheromone trapping during the growing season:
● Counts will be reported by the provincial staff in Saskatchewan.
● Manitoba Agriculture and Rural Initiatives posted low DBM counts which can be reviewed here.
● Alberta Agriculture and Forestry has a live 2016 map reporting Diamondback moth pheromone trap interceptions. A copy of the map (retrieved July 20, 2017) is below for reference.

2017 Wind Trajectories

THE WEEK OF JUNE 15, 2017:

Reverse trajectories (RT)
There were 139 reverse trajectories that were predicted to pass across Alberta and Saskatchewan from the Pacific Northwest between May 26 and June 8.

Forward trajectories (FT)
The following map indicates the origin of forward trajectories predicted to cross the prairies over the next five days. There have been an increased number of winds that have crossed the prairies from the southwest USA and Mexico since June 1.

2017 Wind Trajectories

THE WEEK OF MAY 29, 2017: Wind trajectory data processing by AAFC-Saskatoon Staff began in April. Reverse Trajectories track arriving air masses back to their point of origin while Forward Trajectories predict favourable winds expected to arrive across the Canadian Prairies for the week of May 23, 2017:

Reverse trajectories (RT)
Overall, the number of RTs entering the prairies from the Pacific
Northwest has been lower than average. The map (Fig. 1) shows that the greatest number
of RTs from the Pacific Northwest continued to be across southern Alberta.

Figure 1. Number of Reverse Trajectories (RT) originating in the Pacific Northwest that
arrived at sites across the Canadian prairies from April 1-May 29, 2017.

Weather forecasts (7 day):

Winnipeg: https://weather.gc.ca/city/pages/mb-38_metric_e.html

Brandon: https://weather.gc.ca/city/pages/mb-52_metric_e.html

Saskatoon: https://weather.gc.ca/city/pages/sk-40_metric_e.html

Regina: https://weather.gc.ca/city/pages/sk-32_metric_e.html

Edmonton: https://weather.gc.ca/city/pages/ab-50_metric_e.html

Lethbridge: https://weather.gc.ca/city/pages/ab-30_metric_e.html

Grande Prairie: https://weather.gc.ca/city/pages/ab-31_metric_e.html

Weekly Update – Previous Posts

The following is a list of 2017 Posts – click to review:

Canola scouting chart
Crop protection guides

Diamondback moth

Flax scouting chart

Iceberg reports

Lily leaf beetle

Ticks and Lyme disease

2017 Wind Trajectories

THE WEEK OF MAY 23, 2017: Wind trajectory data processing by AAFC-Saskatoon Staff began in April. Reverse Trajectories track arriving air masses back to their point of origin while Forward Trajectories predict favourable winds expected to arrive across the Canadian Prairies for the week of May 23, 2017:

Reverse trajectories (RT)
Between May 16 and 23 there were 57 RT’s from the Pacific Northwest of USA that crossed the prairies. The first chart (Fig. 1) indicates site specific results for PNW RT’s for each day of the past week. Values reflect the fact that PNW RT’s were lower this week than previous weeks. The greatest number of PNW RT’s continued to be across southern AB (Fig. 2).

Figure 1. Cumulative number of Reverse Trajectories (RT) originating from the Pacific Northwest arriving across the Canadian prairies from May 16-23, 2017 (Olfert et al. 2017).

Figure 2. Number of Reverse Trajectories (RT) originating in the Pacific Northwest that arrived at sites across the Canadian prairies from April 1-May 23, 2017.

Forward trajectories (FT)
No FTs originating from Mexico or southwest USA/Mexico are predicted to cross the prairies over the next 5 days. The following map provides an overview of FTs that have crossed the prairies during the 2017 growing season.

Figure 2. Total number of reverse trajectories originating from the Pacific Northwest of the USA arriving at sites across the Canadian prairies (April 1-May 23, 2017).

Weather forecasts (7 day):

Winnipeg: https://weather.gc.ca/city/pages/mb-38_metric_e.html

Brandon: https://weather.gc.ca/city/pages/mb-52_metric_e.html

Saskatoon: https://weather.gc.ca/city/pages/sk-40_metric_e.html

Regina: https://weather.gc.ca/city/pages/sk-32_metric_e.html

Edmonton: https://weather.gc.ca/city/pages/ab-50_metric_e.html

Lethbridge: https://weather.gc.ca/city/pages/ab-30_metric_e.html

Grande Prairie: https://weather.gc.ca/city/pages/ab-31_metric_e.html