Weather synopsis

This past week (July 28 to August 3, 2020) prairie temperatures were warmest in southeastern Alberta and southwestern Saskatchewan and coolest in southern Manitoba and the Peace River region of Alberta and British Columbia (Fig. 1). Temperatures in the past week represent a switch from previous weeks, where it was warmer in Manitoba than in Alberta. Average 30-day temperatures (July 5 to August 3, 2020) continue to be cooler across most of Alberta than observed in eastern Saskatchewan and Manitoba (Fig. 2). The average 30-day temperature at Winnipeg and Brandon continued to be greater than locations in Alberta and Saskatchewan (Fig. 2).

Figure 1. Observed average temperatures across the Canadian prairies the past seven days (July 28-August 3, 2020).
Figure 2. Observed average temperatures across the Canadian prairies the past 30 days (July 5-August 3, 2020).
Figure 3. Mean temperature difference from Normal the past 30 days (July 1-31, 2020).
Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (13Jul2020). Access the full map at http://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=true&reset=1588297059209

Cumulative rainfall for the past 7 days was lowest across southern regions of Alberta, Saskatchewan and Manitoba (Fig. 4). Cumulative 30-day rainfall was lowest across a large area ranging from southwest Saskatchewan to Saskatoon (Fig. 5). Growing season rainfall (percent of average) is below normal across eastern Saskatchewan and localized areas of Manitoba and above normal across most of Alberta (Fig. 6).

Figure 4. Observed cumulative precipitation across the Canadian prairies the past seven days (July 28-August 5, 2020).
Figure 5. Observed cumulative precipitation across the Canadian prairies the past 30 days (July 5-August 3, 2020).
Figure 6. Percent of average precipitation for the growing season (April 1-August 3, 2020).
Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (04Aug2020). Access the full map at http://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=true&reset=1588297059209

The growing degree day map (GDD) (Base 5 ºC, April 1-August 3, 2020) is below (Fig. 7) while the growing degree day map (GDD) (Base 10 ºC, April 1-August 3, 2020) is shown in Figure 8.

Figure 7. Growing degree day map (Base 5 °C) observed across the Canadian prairies for the growing season (April 1-August 3, 2020).
Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (06Aug2020). Access the full map at http://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=true&reset=1588297059209
Figure 8. Growing degree day map (Base 10 °C) observed across the Canadian prairies for the growing season (April 1-August 3, 2020).
Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (06Aug2020). Access the full map at http://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=true&reset=1588297059209

The highest temperatures (°C) observed across the Canadian prairies the past seven days ranged from <24 to >32 °C (Fig. 9). So far this growing season (as of August 6, 2020), the number of days above 25°C ranges from 0-10 days throughout much of Alberta and into the BC Peace then extends up to 51-60 days in southern Manitoba (Fig. 10).

Figure 9. Highest temperatures (°C) observed across the Canadian prairies the past seven days (April 1-August 3, 2020).
Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (06Aug2020). Access the full map at http://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=true&reset=1588297059209
Figure 10. Number of days above 25 °C observed across the Canadian prairies this growing season (April 1-August 5, 2020).
Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (06Aug2020). Access the full map at http://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=true&reset=1588297059209

The maps above are all produced by Agriculture and Agri-Food Canada. Growers can bookmark the AAFC Current Conditions Drought Watch Maps for the growing season. Historical weather data can be access at the AAFC Drought Watch website, Environment Canada’s Historical Data website, or your provincial weather network.

Predicted bertha armyworm development

Model simulations for August 3, 2020, indicate that BAW development varies across the prairies. Figures 1 and 2 demonstrate that BAW populations near Winnipeg (Fig. 1) are more advanced than populations near Grande Prairie (Fig. 2). Populations near Winnipeg are predicted to be developing to pupae (Fig. 1). BAW populations near Grande Prairie are expected to be primarily in the larval stage (Fig. 2).

Figure 1. Predicted bertha armyworm (Mamestra configurata) phenology at Winnipeg MB as of August 3, 2020.
Figure 2 Predicted bertha armyworm (Mamestra configurata) phenology at Grande Prairie AB as of August 3, 2020.

Weekly Pheromone-baited Trapping Results – Early season detection of bertha armyworm is improved through the use of pheromone-baited unitraps traps deployed in fields across the Canadian prairies.  Click each province name to access moth reporting numbers observed in AlbertaSaskatchewan and Manitoba (as they become available). Check these sites to assess cumulative counts and relative risk in your geographic region but remember in-field scouting is required to apply the economic threshold to manage both this pest and its natural enemies. For convenience, screen shots of the above maps or data have been placed below for Alberta, Saskatchewan, and Manitoba.

Monitoring:

  • Larval sampling should commence once the adult moths are noted.
  • Sample at least three locations, a minimum of 50 m apart.
  • At each location, mark an area of 1 m2 and beat the plants growing within that area to dislodge the larvae.
  • Count them and compare the average against the values in the economic threshold table below:

Scouting tips:
● Some bertha armyworm larvae remain green or pale brown throughout their larval life.
● Large larvae may drop off the plants and curl up when disturbed, a defensive behavior typical of cutworms and armyworms.
● Young larvae chew irregular holes in leaves, but normally cause little damage. The fifth and sixth instar stages cause the most damage by defoliation and seed pod consumption. Crop losses due to pod feeding will be most severe if there are few leaves.
● Larvae eat the outer green layer of the stems and pods exposing the white tissue.
● At maturity, in late summer or early fall, larvae burrow into the ground and form pupae.

Refer to the PPMN Bertha armyworm monitoring protocol for help when performing in-field scouting.  Use the images below (Fig. 4) to help identify the economically important larvae.  Review the 2019 Insect of the Week which featured bertha armyworm and its doppelganger, the clover cutworm! 

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Figure 4. The egg stage (A), larval stage (B), pupal stage (C), and adult stage (D) of bertha armyworm. Photos: Jonathon Williams (AAFC-Saskatoon).

Biological and monitoring information related to bertha armyworm in field crops is posted by the provinces of ManitobaSaskatchewanAlberta and the Prairie Pest Monitoring Network. Also refer to the bertha armyworm pages within the “Field Crop and Forage Pests and their Natural Enemies in Western Canada: Identification and management field guide” which is a free downloadable document as both an English-enhanced or French-enhanced version.

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).

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 3, 2020.
Figure 2. Using a biofix date of May 15, 2020, the projected number of diamondback moth (Plutella xylostella) generations across the Canadian prairies using Climate Normal data.

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.

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Figure 5. Diamondback larva measuring ~8mm long.
Note brown head capsule and forked appearance of prolegs on posterior.
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Figure 6. Diamondback moth pupa within silken cocoon.

Economic threshold for diamondback moth in canola at the advanced pod stage is 20 to 30 larvae/ 0.1  (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).

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Figure 7. Diamondback moth.

Biological and monitoring information for DBM is posted by Manitoba AgricultureSaskatchewan 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 grasshopper development

As of August 3, 2020, the grasshopper model estimates that prairie grasshopper populations are primarily adults (Fig. 1). Based on model simulations, development has been slowest across central and northern regions of Alberta (Fig. 1). The second map provides an overview of where oviposition is predicted to have started (Fig. 2). The yellow and red areas show that oviposition has begun across southern Manitoba and southeastern Saskatchewan (Fig. 2).

Figure 1. Predicted average development stages of grasshopper (Melanoplus sanguinipes) populations across the Canadian prairies (as of August 3, 2020).
Figure 2. Predicted oviposition for (Melanoplus sanguinipes) populations across the Canadian prairies (as of August 3, 2020).

The two graphs compare grasshopper development at Saskatoon (Fig. 3) and Brandon (Fig. 4). Near Saskatoon, grasshopper populations are expected to be mainly in the adult stage with oviposition beginning to occur over the past week (Fig. 3). Around Brandon, adult emergence is complete and oviposition should be well underway (Fig. 4).

Figure 3. Predicted grasshopper (Melanoplus sanguinipes) phenology at Saskatoon SK. Values are based on model simulations (April 1-August 3, 2020).
Figure 4. Predicted grasshopper (Melanoplus sanguinipes) phenology at Brandon MB. Values are based on model simulations (April 1-August 3, 2020).

Biological and monitoring information related to grasshoppers in field crops is posted by Manitoba AgricultureSaskatchewan AgricultureAlberta Agriculture and Forestry, the BC Ministry of Agriculture and the Prairie Pest Monitoring Network.  Also refer to the grasshopper pages within the “Field Crop and Forage Pests and their Natural Enemies in Western Canada: Identification and management field guide” (Philip et al. 2018) as an English-enhanced or French-enhanced version.

Lygus bug in canola

On the Canadian prairies, lygus bugs (Heteroptera: Miridae) are normally a complex of several native species usually including Lygus lineolaris, L. keltoni, L. borealis, L. elisus although several more species are distributed throughout Canada. The species of Lygus forming the “complex” can vary by host plant, by region or even seasonally.

Lygus bugs are polyphagous (i.e., feed on plants belonging to several Families of plants) and multivoltine (i.e., capable of producing multiple generations per year). Both the adult (Fig. 1) and five nymphal instar stages (Fig. 2) are a sucking insect. Adults overwinter in northern climates. The economic threshold for Lygus in canola is applied at late flower and early pod stages.  

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Figure 1. Adult Lygus lineolaris (5-6 mm long) (photo: AAFC-Saskatoon).
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Figure 2. Fifth instar lygus bug nymph (3-4 mm long) (photo: AAFC-Saskatoon).

Damage: Lygus bugs have piercing-sucking mouthparts and physically damage the plant by puncturing the tissue and sucking plant juices. The plants also react to the toxic saliva that the insects inject when they feed. Lygus bug infestations can cause alfalfa to have short stem internodes, excessive branching, and small, distorted leaves. In canola, lygus bugs feed on buds and blossoms and cause them to drop. They also puncture seed pods and feed on the developing seeds causing them to turn brown and shrivel.

Scouting tips to keep in mind: Begin monitoring canola when it bolts and continue until seeds within the pods are firm. Since adults can move into canola from alfalfa, check lygus bug numbers in canola when nearby alfalfa crops are cut.

Sample the crop for lygus bugs on a sunny day when the temperature is above 20 °C and the crop canopy is dry. With a standard insect net (38 cm diameter), take ten 180 ° sweeps. Count the number of lygus bugs in the net. Sampling becomes more representative IF repeated at multiple spots within a field so sweep in at least 10 locations within a field to estimate the density of lygus bugs. In fact, sampling is most accurate when repeated at a total of 15 spots within the field.  Samples can be taken along or near the field margins. Calculate the cumulative total number of lygus bugs and then consult the sequential sampling chart (Figure 3). 

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Figure 3. Sequential sampling for lygus bugs at late flowering stage in canola.

If the total number is below the lower threshold line (Fig. 3), no treatment is needed. If the total is below the upper threshold line, take more samples. If the total is on or above the upper threshold line, calculate the average number of lygus bugs per 10-sweep sample and consult the economic threshold tables (Tables 1 and 2).

The economic threshold for lygus bugs in canola covers the end of the flowering (Table 1) and the early pod ripening stages (Table 2). Once the seeds have ripened to yellow or brown, the cost of controlling lygus bugs may exceed the damage they will cause prior to harvest, so insecticide application is not warranted. Consider the estimated cost of spraying and expected return prior to making a decision to treat a crop. 

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Remember that insecticide applications at bud stage in canola have not been proven to result in an economic benefit in production.  The exception to this is in the Peace River region where early, dry springs and unusually high densities of lygus bug adults can occasionally occur at bud stage.  In this situation, high numbers of lygus bugs feeding on moisture-stressed canola at bud stage is suspected to result in delay of flowering so producers in that region must monitor in fields that fail to flower as expected.

How to tell them apart: The 2019 Insect of the Week’s doppelganger for Wk 15 was lygus bug versus the alfalfa plant bug while Wk 16 featured lygus bug nymphs vs. aphids!  Both posts include tips to to discern the difference between when doing in-field scouting!

Biological and monitoring information related to Lygus in field crops is posted by the provinces of Manitoba or Alberta fact sheets or the Prairie Pest Monitoring Network’s monitoring protocol.  Also refer to the Lygus pages within the new “Field Crop and Forage Pests and their Natural Enemies in Western Canada: Identification and management field guide” – both English or French versions are available.

Thrips in canola

Thrips in canola (Thynsanoptera) – While scouting at this time of year, curled canola pods may be encountered.  The culprits are quite possibly thrips.

Figure 1. Thrips damage observed in canola in the northeast of Saskatchewan in July 2016 (Photo: AAFC-Saskatoon, Olfert 2016).

Damage: Flower thrips (Thysanoptera) are pests of a broad range of plants including cereals and broadleaved crops such as canola. Thrips are minute, slender-bodied insects with rasping-sucking mouthparts and feed by rasping the surface of canola buds and sucking up plant fluids. 

Biology: Thrips have six life stages: egg, two larval stages, a prepupal and pupal stage and an adult. Both adults and nymphs cause damage by feeding on the flower and buds. Limited surveys in 1999 in Saskatchewan and Alberta indicated that the predominant species were Frankliniella tritici (flower thrip) followed by Thrips tabaci (onion thrip) and T. vulgatissimus (no common name).

In canola, pods damaged by thrips are often curled and tend to drop prematurely.  Some species, such as T. vulgatissimus have been credited with contributing to pollination.

Read more about thrips in canola by accessing this article by Olfert et al. 1998).

Ladybird beetles and mummies

Ladybird beetle larvae (Fig. 1), pupae (Fig. 2), and adults (Fig. 3) can all be found in fields at this time of year.  Take a look at the various stages and the many patterns of native and introduced species to recognize these as Field Heroes!  Ladybird beetles are categorized as general predators and will feed on several species of arthropods but are partial to aphids.  

Figure 1. Ladybird beetle larva (photo credit: AAFC-Beaverlodge)
Figure 2. Ladybird beetle pupa (photo credit: AAFC-Beaverlodge).
Figure 3. Ladybird beetle (Coccinella septempunctata) (photo credit: AAFC-Beaverlodge)

Another “beneficial” found in fields at this point in the season are mummified aphids (Fig. 4). The “mummy” contains a maturing parasitoid wasp which will emerge from the host and seek other aphids to parasitize. Read more about the amazing Aphidiinae wasps by accessing the pages from the  “Field Crop and Forage Pests and their Natural Enemies in Western Canada: Identification and Field Guide“.  The guide is available as a free downloadable document in both an English-enhanced or French-enhanced version.

Figure 4. An aphid “mummy” adhered to a wheat awn.  A “mummy” is the aphid host transformed to enclose a soon-to-emerge parasitoid wasp (photo credit: AAFC-Beaverlodge).

West nile virus risk

Health Canada posts information related to West Nile Virus in Canada and also tracks West Nile Virus through humanmosquitobird and horse surveillance.  Link here to access the most current weekly update (reporting date July 12-18, 2020; retrieved Aug 11, 2020). The screenshot below (retrieved Aug 11, 2020) serves as reference but access that Health Canada information here.

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The following is offered to predict when Culex tarsalis, the vector for West Nile Virus, will begin to fly across the Canadian prairies (Fig. 1). This week, regions most advanced in degree-day accumulations for Culex tarsalis are shown in the map below (yellow, orange then red highlighted areas).  As of August 5, 2020 (Fig. 1), areas highlighted yellow and more imminently orange are approaching sufficient heat accumulation for mosquitoes to emerge.  Areas highlighted red NOW HAVE Culex tarsalis flying (Fig. 1) – protect yourself by wearing DEET!  

Figure 1. Predicted development of Culex tarsalis, across the Canadian prairies (as of August 5, 2020).

Stored product pests

The Canadian Grain Commission’s website has an online key to stored product pests.  Growers managing grain storage can find an online identification tool for stored product pests (e.g., Rusty grain beetleRed flour beetleConfused flour beetleSaw-toothed grain beetle, and more).  The online tool features excellent diagnostic photos.  A screen shot of the Canadian Grain Commission’s “Identify an Insect” webpage is included below for reference.

Provincial insect pest report links


Provincial entomologists
provide insect pest updates throughout the growing season so link to their information: 

Manitoba‘s Crop Pest Updates for 2020 are available. Access the August 5, 2020 report. The summary indicates that, “Grasshoppers are currently the biggest insect concern. Some sunflower midge has been observed in sunflowers in the Eastern region, mainly around field edges, which is typical for this insect. Lygus bugs have also been noted in sunflower fields. Diamondback moth larvae in canola remains a concern for growers and agronomists in the Eastern region, with lots of scouting and some limited insecticide applications occurring.”

Saskatchewan‘s Crop Production News (for Issue 6). Read Issue 5 which includes articles on Bertha armyworm, Cabbage seedpod weevil,  FieldWatch – Fostering Communication Between Applicators and Producers, and Look What the Wind Blew in! Diamondback Moths Arrived Early This Spring. Issue #4 included articles on Pest Scouting 101: Mid-Summer, and The Wheat Midge.

•  Alberta Agriculture and Forestry’s Agri-News occasionally includes insect-related information or Twitter users can connect to #ABBugChat Wednesdays at 10:00 am.

Crop report links

Click the provincial name below to link to online crop reports produced by:

• Manitoba Agriculture and Rural Initiatives – Other viewing options include subscribing to receive or access a PDF of August 4, 2020 report.

• Saskatchewan Agriculture  or access a PDF of July 28-August 3, 2020 report.

• Alberta Agriculture and Forestry or access a PDF of July 28, 2020 report.

The following crop reports are also available:

• The United States Department of Agriculture (USDA) produces a Crop Progress Report (read the August 3, 2020 edition).

• The USDA’s Weekly Weather and Crop Bulletin (read the August 4, 2020 edition). 

Previous posts

Click to review these earlier 2020 Posts (organized alphabetically):

    • 2019-2020 Risk and forecast maps

    • Alfalfa weevil (Wk08)

    • Aster leafhopper (Wk05)

    • Beetle data please! (Wk03)

    • Cereal aphid APP (Wk11)

    • Crop protection guides (Wk02)

    • Cutworms (Wk02)

    • Diamondback moth (Wk11)

    • Flea beetles (Wk02)

    • Field heroes (Wk14)

    • John Doane (Wk10)

    • Monarch migration (Wk10)

    • Pea leaf weevil (Wk11)

    • Pea leaf weevil – predicted development (Wk09)

    • Prairie provincial insect webpages (Wk02)

    • Wheat midge (Wk13).

    • Scouting charts – canola and flax (Wk02)

    • Ticks and Lyme Disease (Wk06)

    • Wind trajectories (Wk09)

    • West nile virus (Wk14)

Oat Pests / Feature Entomologist: Héctor Cárcamo

This week’s Insect of the Week feature crop is oat, a plant grown across the Prairies for both food production and livestock feed. Our feature entomologist this week is Héctor Cárcamo.

Oat – AAFC

A versatile food and feed crop, almost 90% of Canadian oat production takes place across Manitoba, Saskatchewan and Alberta. In 2019 Canada was the world’s third largest oat producer, and number one oat exporter. In the same year, total Prairie production seeded over 1.3 million hectares (3.2 million acres) was over 3.8 million metric tonnes (4.2 million US tons).

Various pest species target oat. Monitoring and scouting protocols as well as economic thresholds (when available) are found in Field Crop and Forage Pests and their Natural Enemies in Western Canada: Identification and Management and the Cutworm Pests of Crops on the Canadian Prairies: Identification and Management Field Guide. Additional monitoring protocols exist to control certain pests.

Oat field – AAFC
Oat Pests
  • Army cutworm
  • Armyworm
  • Black grass bugs
  • Cereal leaf beetle
  • Chinch bug
  • Darksided cutworm
  • Dingy cutworm
  • English grain aphid
  • Fall armyworm
  • Fall field cricket
  • Glassy cutworm
  • Grasshoppers
  • Green grass bugs
  • Greenbug
  • Oat-birdcherry aphid
  • Pale western cutworm
  • Redbacked cutworm
  • Rice leaf bug
  • Say stink bug
  • Variegated cutworm
  • Wheat head armyworm
  • Wheat stem maggot
  • Wireworms
English grain aphids – AAFC

ENTOMOLOGIST OF THE WEEK: Héctor Cárcamo

Name: Héctor Cárcamo
Affiliation: AAFC, Lethbridge Research and Development Centre
Contact Information: hector.carcamo@canada.ca

How do you contribute in insect monitoring or surveillance on the Prairies?

I contribute by helping to develop survey protocols for resurging native insect pests (wheat stem sawfly, 2003) or new invasive pests (pea leaf weevil, 2005; cereal leaf beetle, 2007). With my team we also conduct surveys to tackle research questions such as farm threshold validations or landscape studies for lygus bugs, cabbage seedpod weevil and cereal leaf beetle. Finally, I collaborate with various researchers in the writing of scientific articles from survey data.  

In your opinion, what is the most interesting field crop pest on the Prairies?

It is difficult to name just one! I really like the wheat stem sawfly because it is so well studied and this allows us to ask more refined ecological questions. Plus it forces us to use non-chemical methods to manage it. But if I had to choose only one to work on…I would pick lygus bugs because they are an extremely challenging and complex pest with populations that can increase rapidly. It seems to be almost ‘unpredictable”! Also it is highly polyphagous and as a species complex, extremely widespread geographically – the tarnished plant bug ranges from Guatemala to Alaska!

What is your favourite beneficial insect?

Well, this is an easy one: a carabid ground beetle of course, my Twitter name gives this one away: @hectorcarabido! Why: because they are so diverse, easy to catch and easy to identify to species. They are also very popular so it is easy to start a conversation over carabid beetles with most entomologists.

Tell us about an important/interesting project you are working on right now.

I am excited about biological control and I am currently leading a national study on biocontrol of cabbage seedpod weevil and I am also equally excited to start the one that got delayed due to COVID-19: A survey of parasitism of lygus nymphs in emerging and established crops.

What tools, platforms, etc. do you use to communicate with your stakeholders?

I regularly do interviews with the farm media and work with the technology transfer platforms used by the various commodity associations that fund our research. I have also contributed to our AAFC fact sheets or other technology transfer publications. Recently I have started to use Twitter and I have participated regularly in the weekly #abbugchat.

Weekly Update

Greetings!

Week 15 and our Staff are out performing surveys, in-field monitoring and are active at various tech-transfer events across the prairies!  Please bookmark the Blog or subscribe to receive the latest growing season information!

Please access the complete Weekly Update either as a series of Posts for Week 15 (July 18, 2019) OR a downloadable PDF. Be sure to check out the Insect of the Week – the rest of the growing season features doppelgangers to aid in-field scouting!

Questions or problems accessing the contents of this Weekly Update?  Please e-mail either Dr. Meghan Vankosky or Jennifer Otani.  Past “Weekly Updates” can be accessed on our Weekly Update page.

Subscribe to the Blog by following these easy steps!

Weather synopsis

Prairie temperatures continue to be cooler than average. Though temperatures this week were approximately 2 °C warmer than last week (July 8-14, 2019), the seven-day average temperature was 0.5 °C cooler than normal (Fig. 1).  The warmest temperatures were observed across MB while temperatures were cooler in western SK and across AB. 

Figure 1. Average temperature (°C) across the Canadian prairies the past seven days (July 8-14, 2019).

Across the prairies, 30-day (June 14 – July 14, 2019) average temperatures have been approximately 1 °C cooler than normal (Fig. 2). Average 30-day temperatures were 0 to 2 °C warmer than average across MB and 0 to 2 °C cooler than average in SK and AB. Growing season temperatures (April 1-July 14, 2019) have been 1 °C cooler than average; the warmest temperatures were observed across the southern prairies (Fig. 3). 

Figure 2. Average temperature (°C) across the Canadian prairies the past 30 days (June 14-July 14, 2019).
Figure 3. Average temperature (°C) across the Canadian prairies for the growing season (April 1-July 14, 2019).
Figure 4. Mean temperature difference from Normal (°C) observed across the Canadian prairies the past 30 days (June 18-July 15, 2019).  
Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (18Jul2019).  Access the full map at http://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=true

This past week significant rainfall amounts were reported MB and southeastern SK while minimal rainfall was reported across southwestern SK and southern AB (Fig. 5). 

Figure 5. Cumulative precipitation observed the past seven days across the Canadian prairies (July 8-14, 2019).

Across the prairies, rainfall amounts for the past 30 days have been highly variable (Fig. 6). Dry conditions continue across much of southern AB. Rainfall was well above average in SK.  

Figure 6. Cumulative precipitation observed the past seven days across the Canadian prairies (June 15-July 15, 2019).

Growing season (April 1 – July 14, 2019) rainfall amounts have been below average across southern regions of AB, central SK, and central MB (Fig. 7). 

Figure 6. Cumulative precipitation observed over the growing season (April 1-July 15, 2019) across the Canadian prairies.
Figure 7. Percent of average precipitation observed across the Canadian prairies for the growing season (April 1-July 17, 2019).  
Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (18Jul2019).  Access the full map at http://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=true

Based on modeled soil moisture (Fig. 8), recent rains have improved soil moisture values across a large area of SK and MB. Predicted soil moisture continues to be low across large regions of southern and central areas of AB and western SK. 

Figure 8.  Modeled soil moisture (%) across the prairies (up to July 15, 2019).

The growing degree day map (GDD) (Base 5 ºC, April 1-July 14, 2019) is below (Fig. 9):

Figure 9. Growing degree day (Base 5 ºC) across the Canadian prairies for the growing season (April 1-July 14, 2019).

The growing degree day map (GDD) (Base 10 ºC, April 1-July 14, 2019) is below (Fig. 10):

Figure 10. Growing degree day (Base 10 ºC) across the Canadian prairies for the growing season (April 1-July 14, 2019).

The lowest temperatures (°C) observed the past seven days ranged from at least 14 down to at least 2 °C in the map below (Fig. 11).

Figure 11. Lowest temperatures (°C) observed across the Canadian prairies the past seven days (to July 17, 2019).  
Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (18Jul2019).  Access the full map at http://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=true

The highest temperatures (°C) observed the past seven days ranged from less than 16 up to at least 30 °C in the map below (Fig. 12).

Figure 12. Highest temperatures (°C) observed across the Canadian prairies the past seven days (to July 17, 2019).  
Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (18Jul2019).  Access the full map at http://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=true

The maps above are all produced by Agriculture and Agri-Food Canada.  Growers can bookmark the AAFC Drought Watch Maps for the growing season. 

Wheat midge

Wheat Midge (Sitodiplosis mosellana) – Where wheat midge are present, cool, dry conditions in May and June have resulted in delayed emergence of adults. Wheat midge larvae have moved to the soil surface and pupae are appearing.  In some locations adults should be beginning to emerge. The wheat midge model predicts that 44% (45% last week) of the population are in the larval  cocoon stage and 37% (47% last week) of the population is predicted to have moved to the soil surface. This week 12% (7% last week) is predicted to be in the pupal stage. Adults continue to emerge in localized areas in localized areas across all three provinces. 

The first map (Fig. 1) indicates the percent of the population that is in the pupal stage.  The second map (Fig. 2) indicates that less than 10% of the adult population has emerged.  The last map (Fig. 3) indicates that oviposition may be occurring in localized areas. It should be noted that, based on fall surveys in 2018, wheat midge populations were expected to be low across most of AB and SK.

Figure 1.  Predicted percent of wheat midge (Sitodiplosis mosellana) populations at PUPAL STAGE across the Canadian prairies (as of July 15, 2019).
Figure 2. Predicted percent of wheat midge (Sitodiplosis mosellana) populations at ADULT STAGE across the Canadian prairies (as of July 15, 2019).
Figure 3. Predicted percent of wheat midge (Sitodiplosis mosellana) populations where egg laying has begun across the Canadian prairies (as of July 15, 2019).

Monitoring:
When monitoring wheat fields, pay attention to the synchrony between flying midge and anthesis.

In-field monitoring for wheat midge should be carried out in the evening (preferably after 8:30 pm or later) when the female midges are most active. On warm (at least 15ºC), calm evenings, the midge can be observed in the field, laying their eggs on the wheat heads (photographed by AAFC-Beav-S. Dufton & A. Jorgensen below). Midge populations can be estimated by counting the number of adults present on 4 or 5 wheat heads. Inspect the field daily in at least 3 or 4 locations during the evening.

REMEMBER that in-field counts of wheat midge per head remain the basis of economic threshold decision.  Also remember that the parasitoid, Macroglenes penetrans (photographed by AAFC-Beav-S. Dufton below), is actively searching for wheat midge at the same time.  Preserve this parasitoid whenever possible and remember your insecticide control options for wheat midge also kill these beneficial insects which help reduce midge populations.

Economic Thresholds for Wheat Midge:
a) To maintain optimum grade: 1 adult midge per 8 to 10 wheat heads during the susceptible stage.
b) For yield only: 1 adult midge per 4 to 5 heads. At this level of infestation, wheat yields will be reduced by approximately 15% if the midge is not controlled.

Inspect the developing kernels for the presence of larvae and the larval damage. 

Wheat midge and its doppelganger, the lauxanid fly, were featured as the Insect of the Week (for Wk10).  Check that post for help with in-field scouting for this economic pest of wheat!  The differences between midges and parasitoid wasps are featured as the current Insect of the Week (for Wk11).  Not all flying insects are mosquitoes nor are they pests – many are important parasitoid wasps that actually regulate insect pest species in our field crops.

Information related to wheat midge biology and monitoring can be accessed by linking to your provincial fact sheet (Saskatchewan Agriculture or Alberta Agriculture & Forestry).  A review of wheat midge on the Canadian prairies was published by Elliott, Olfert, and Hartley in 2011.  

Alberta Agriculture and Forestry has a YouTube video describing in-field monitoring for wheat midge.  

More information about Wheat midge 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 Wheat midge pages but remember the guide is available as a free downloadable document as both an English-enhanced or French-enhanced version.

Predicted grasshopper development

Grasshopper Simulation Model Output – The grasshopper simulation model will be used to monitor grasshopper development across the prairies. Weekly temperature data collected across the prairies is incorporated into the simulation model which calculates estimates of grasshopper development stages based on biological parameters for Melanoplus sanguinipes (Migratory grasshopper).

Cool temperatures continue to result in reduced grasshopper developmental rates. Based on model runs, approximately 7% (12.5% last week) of the population is in the first instar, 12% (23% last week) is predicted to be in the second instar, and 27% (32% last week)  is in the third instar, 30% (21% last week) are predicted to be in the fourth instar and 18% (4% last week) are predicted to be in the fifth instar.  As of July 14, 1% of melanopline species are predicted to be in the adult stage. 

The following map (Fig. 1) indicates that grasshopper populations across the southern prairie are mostly in the third and fourth instars. Grasshopper development has been greatest near Winnipeg MB.

Figure 1. Predicted development stages of grasshopper (Melanoplus sanguinipes) populations across the Canadian prairies (as of July 15, 2019). 

Last week, the Insect of the Week’s Doppelganger featured GRASSHOPPERS!!!  Check out the excellent nymph photos to help your in-field scouting!

Biological and monitoring information related to grasshoppers in field crops is posted by Manitoba AgricultureSaskatchewan AgricultureAlberta Agriculture and Forestry, the BC Ministry of Agriculture and the Prairie Pest Monitoring Network.  Also refer to the grasshopper pages within the “Field Crop and Forage Pests and their Natural Enemies in Western Canada: Identification and management field guide” which is available as a free downloadable document in either an English-enhanced or French-enhanced version.

Bertha armyworm monitoring

Bertha armyworm (Lepidoptera: Mamestra configurata– Predictive model updates are completed for the growing season but can be reviewed here (Wk 14).  

Important – Watch for updates from your provincial monitoring networks who are compiling cumulative pheromone-baited trap interceptions to assess risk levels in AlbertaSaskatchewan (updated 10Jul2019), and Manitoba (look on pg 7).

Biological and monitoring information related to bertha armyworm in field crops is posted by the provinces of ManitobaSaskatchewanAlberta and the Prairie Pest Monitoring Network. Also refer to the bertha armyworm pages within the “Field Crop and Forage Pests and their Natural Enemies in Western Canada: Identification and management field guide” which is a free downloadable document as both an English-enhanced or French-enhanced version.

Refer to the PPMN Bertha armyworm monitoring protocol for help when performing in-field scouting.  Use the images below (Fig. 3) to help identify egg masses and the economically important larvae in canola.

Figure 3. Stages of bertha armyworm from egg (A), larva (B), pupa (C) to adult (D).
Photos: J. Williams (Agriculture and Agri-Food Canada)

Now is the time to do in-field scouting for this insect pest.  Review the Insect of the Week which features bertha armyworm and its doppelganger, the clover cutworm!

Lygus in canola

Lygus bugs (Lygus spp.) – The Insect of the Week’s doppelganger is the lygus bug versus the alfalfa plant bug. It includes tips to to discern the difference between these plant bug complexes when doing in-field scouting!

The economic threshold for Lygus in canola is applied at late flower and early pod stages.  

Adult L. lineolaris (5-6 mm long) (photo: AAFC-Saskatoon).
Fifth instar lygus bug nymph (3-4 mm long) (photo:  AAFC-Saskatoon).

Damage: Lygus bugs have piercing-sucking mouthparts and physically damage the plant by puncturing the tissue and sucking plant juices. The plants also react to the toxic saliva that the insects inject when they feed. Lygus bug infestations can cause alfalfa to have short stem internodes, excessive branching, and small, distorted leaves. They feed on buds and blossoms and cause them to drop. They also puncture seed pods and feed on the developing seeds causing them to turn brown and shrivel.

Scouting tips to keep in mind: Begin monitoring canola when it bolts and continue until seeds within the pods are firm. Since adults can move into canola from alfalfa, check lygus bug numbers in canola when nearby alfalfa crops are cut.

Sample the crop for lygus bugs on a sunny day when the temperature is above 20°C and the crop canopy is dry. With a standard insect net (38 cm diameter), take ten 180° sweeps. Count the number of lygus bugs in the net.

Sampling becomes more representative IF repeated at multiple spots within a field.  For lygus bug monitoring, sampling is most accurate when repeated at a total of 15 spots within the field.  Samples can be taken along or near the field margins. Calculate the cumulative total number of lygus bugs and then consult the sequential sampling chart (Figure C). 

If the total number is below the lower threshold line, no treatment is needed. If the total is below the upper threshold line, take more samples. If the total is on or above the upper threshold line, calculate the average number of lygus bugs per 10-sweep sample and consult the economic threshold table.

Sequential sampling for lygus bugs at late flowering stage in canola.

The economic threshold for lygus bugs in canola covers the end of the flowering (Table 1) and the early pod ripening stages (Table 2). Once the seeds have ripened to yellow or brown, the cost of controlling lygus bugs may exceed the damage they will cause prior to harvest, so insecticide application is not warranted.

Consider the estimated cost of spraying and expected return prior to making a decision to treat a crop. 

Remember that insecticide applications at bud stage in canola have not been proven to result in an economic benefit in production.  The exception to this is in the Peace River region where early, dry springs and unusually high densities of lygus bug adults can occasionally occur at bud stage.  In this situation, high numbers of lygus bugs feeding on moisture-stressed canola at bud stage is suspected to result in delay of flowering so producers in that region must monitor in fields that fail to flower as expected.

Table 1.  Economic thresholds for lygus bugs in canola at late flowering and early pod stages (Wise and Lamb 1998).

1 Canola crop stage estimated using Harper and Berkenkamp 1975).
2 Economic thresholds are based on an assumed loss of 0.1235 bu/ac per lygus bug caught in 10 sweeps (Wise and Lamb. 1998. The Canadian Entomologist. 130: 825-836).

Table 2.  Economic thresholds for lygus bugs in canola at pod stage (Wise and Lamb 1998).

 3 Economic thresholds are based on an assumed loss of 0.0882 bu/ac per lygus bug caught in 10 sweeps (Wise and Lamb. 1998. The Canadian Entomologist. 130: 825-836).

Biological and monitoring information related to Lygus in field crops is posted by the provinces of Manitoba or Alberta fact sheets or the Prairie Pest Monitoring Network’s monitoring protocol.  Also refer to the Lygus pages within the new “Field Crop and Forage Pests and their Natural Enemies in Western Canada: Identification and management field guide” – both English or French versions are available.

Cabbage seedpod weevil

Cabbage seedpod weevil (Ceutorhynchus obstrictus) –  There is one generation of CSPW per year and the overwintering stage is the adult which is an ash-grey weevil measuring 3-4mm long (Refer to lower left photo).  Adults typically overwinter in soil beneath leaf litter within shelter belts and roadside ditches.

Monitoring:  

  • Begin sampling when the crop first enters the bud stage and continue through the flowering.
  • Sweep-net samples should be taken at ten locations within the field with ten 180° sweeps per location.  
  • Count the number of weevils at each location. Samples should be taken in the field perimeter as well as throughout the field.  
  • Adults will invade fields from the margins and if infestations are high in the borders, application of an insecticide to the field margins may be effective in reducing the population to levels below which economic injury will occur.  
  • An insecticide application is recommended when three to four weevils per sweep are collected and has been shown to be the most effective when canola is in the 10 to 20% bloom stage (2-4 days after flowering starts). 
  • Consider making insecticide applications late in the day to reduce the impact on pollinators.  Whenever possible, provide advanced warning of intended insecticide applications to commercial beekeepers operating in the vicinity to help protect foraging pollinators.  
  • High numbers of adults in the fall may indicate the potential for economic infestations the following spring.

Damage: Adult feeding damage to buds is more evident in dry years when canola is unable to compensate for bud loss.  Adults mate following a pollen meal then the female will deposit a single egg through the wall of a developing pod or adjacent to a developing seed within the pod (refer to lower right photo).  Eggs are oval and an opaque white, each measuring ~1mm long.  Typically a single egg is laid per pod although, when CSPW densities are high, two or more eggs may be laid per pod.

There are four larval instar stages of the CSPW and each stage is white and grub-like in appearance ranging up to 5-6mm in length (refer to lower left photo).  The first instar larva feeds on the cuticle on the outside of the pod while the second instar larva bores into the pod, feeding on the developing seeds.  A single larva consumes about 5 canola seeds.  The mature larva chews a small, circular exit hole from which it drops to the soil surface and pupation takes place in the soil within an earthen cell.  Approximately 10 days later, the new adult emerges to feed on maturing canola pods.  Later in the season these new adults migrate to overwintering sites beyond the field.

Albertan growers can report in-field CSPW scouting data then check the online map posted by Alberta Agriculture and Forestry (screenshot retrieved 18Jul2019 provided below as reference).

Please find additional detailed information for CSPW in fact sheets posted by Alberta Agriculture and ForestrySaskatchewan Agriculture, or the Prairie Pest Monitoring Network.  Also refer to the cabbage seedpod weevil pages within the new “Field Crop and Forage Pests and their Natural Enemies in Western Canada: Identification and management field guide” – both English or French versions are available.

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.

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.

Economic threshold for diamondback moth in canola at the advanced pod stage is 20 to 30 larvae/ 0.1  (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 3. Diamondback moth.

Biological and monitoring information for DBM is posted by Manitoba AgricultureSaskatchewan 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.

West Nile Virus and Culex tarsalis

West Nile Virus Risk –  Reminder – In 2018, there were 426 human clinical cases of West Nile virus (WNV) in Canada (Fig. 1). 

Figure 1. Geographic distribution of WNV human clinical cases and asymptomatic infections in Canada, 2018.
Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (11Jul2019).  Access the full map at https://www.canada.ca/en/public-health/services/publications/diseases-conditions/west-nile-virus-surveillance/2018/november-11-december-15-week-46-50.html

Health Canada posts information related to West Nile Virus in Canada.  Health Canada also tracks WNV through humanmosquitobird and horse surveillance.  Link here to access the most current weekly update (July 6, 2019). The screenshot below was retrieved 18Jul2019 as reference but access that information here.

The Canadian Wildlife Health Cooperative compiles and posts information related to their disease surveillance for West Nile Virus in birds.  Take note of the provincial distribution of positive WNV birds in 2018 (table posted below as reference).

The following is offered to predict when Culex tarsalis will begin to fly across the Canadian prairies (Fig. 2). Protect yourself by wearing DEET!  This week, regions most advanced in degree-day accumulations for Culex tarsalis, the vector for West Nile Virus, are shown in the map below.  Areas highlighted yellow in the map below (Fig. 2) are on the verge of approaching sufficient heat accumulation for mosquitoes to emerge.  Areas highlighted lime green should be preparing for C. tarsalis flight.

Figure 2. Predicted development of Culex tarsalis, across the Canadian prairies (as of July 14, 2019).

Once adults emerge, the following map demonstrates how quickly a Culex tarsalis mosquito carrying WNV can become fully infective (i.e., when it has accumulated 109 base 14.3° degree days) – it’s a matter of days, depending on the region (Figure 3).

Preparing and protecting grains for market

REMINDER – A few helpful tools to keep at your finger tips:

Since May we have posted our prairie provinces’ searchable PDFs of Crop Production Guides.

Keeping It Clean has information to help prepare and protect your grains for market.  Check out their site to find important information.  Learn more about avoiding malathion in bins storing canola, access their spray to swath calculator, and access a pre-harvest glyphosate staging guide

The Canadian Grain Commission has information to help you manage stored grain.  Read tips to prepare your bins to prevent insect infestations.  If there are insects in your grain, use their online diagnostic tools to help identify the problem species.  If pest species are confirmed, there are control options – read more to make the right choice for your grain storage system and your specific grain.

Interested in signing up for Canadian Grain Commission’s Harvest Sample Program?

Field Events – Speak to an entomologist

Public summer field events – Coming to a field near you –  Prairie field crop entomologists are already scheduled to be at these 2019 field tour events from May-August (be sure to re-confirm dates and details as events are finalized):

•  July 22, 2019: Pulse grower gathering held near Three Hills AB.  Check Alberta Pulse Growers Event Page for more information.  Entomologists presenting: Graduate students from Dr. Maya Evenden’s (U of A) working on pea leaf weevil.

•  July 23-24, 2019: Crop Diagnostic School, Scott Saskatchewan. Read more about this event.  Entomologists presenting: Meghan Vankosky, Tyler Wist.

•  July 24, 2019: Crops-a-Palooza. Held at Canada-Manitoba Crop Diversification Centre (CMCDC), Carberry, Manitoba. Read more about this event. Entomologist participating: John Gavloski, Vincent Hervet, Tharshi Nagalingam, Bryan Cassone.

•  July 25, 2019: SARDA Summer Field Tour, Falher, Alberta.  Read more about this event.  Entomologist participating: Jennifer Otani, Shelby Dufton.

•  August 8, 2019:  2019 Wheatstalk to be held at Teepee Creek AB.  View event info/registration details.   Entomologists tentatively participating: Jennifer Otani, Shelby Dufton, Amanda Jorgensen, Boyd Mori.

  August 8, 2019. Horticulture School. Agriculture and Agri-Food Canada Research Farm, Portage la Prairie, Manitoba. View event info/registration details.  Entomologist presenting: John Gavloski, Kyle Bobiwash.

Provincial Insect Pest Report Links

Provincial entomologists provide insect pest updates throughout the growing season so we link to their most recent information: 

Manitoba‘s Crop Pest Updates for 2019 are posted here. Access Issue #9 posted July 17, 2019 which notes grasshopper, thistle caterpillar, green cloverworm and aphids in peas. There are also helpful photos and descriptions of grasshopper instar stages plus scouting tips to detect European corn borer egg masses.

Saskatchewan‘s Crops Blog Posts includes a segment on “Economic thresholds” by Kaeley Kindrachuk posted in May 2019. Also access the Crop Production News with Issues:

•  Alberta Agriculture and Forestry’s Agri-News includes an insect-related item in the July 8, 2019 edition with an important reminder that field scouting in July can lead to a more successful crop.

Crop report links

Crop reports are produced by:

The following crop reports are also available:

Previous Posts

Click to review these earlier 2019 Posts:

2019 Risk and forecast maps – Week 2

Alfalfa weevil – Week 11

Bertha armyworm (predicted development) – Week 12

Cabbage seedpod weevil – Week 11
Cereal aphid manager APP – Week 12
Cereal leaf beetle – Week 9
Crop protection guides – Week 6
Cutworms – Week 5

Field heroes – Week 6
Flea beetles – Week 5

Grasshoppers – Week 10

Insect scouting chart for Canola – Week 5
Insect scouting chart for Flax – Week 5

Monarch migration – Week 13

Painted lady butterfly – Week 8
Pea leaf weevil – Week 10
Prairie Crop Disease Monitoring Network – Week 11

Ticks and Lyme disease – Week 4
Timely IOTW to review – Week 13

Weather Radar – Week 6
Wildfires – Week 8

Wind trajectories – Review Page for list of PDFs for Weeks 1-12

Insect of the Week: Doppelgangers: Lygus bug vs. Alfalfa plant bug

The case of lygus bug versus the alfalfa plant bug: It is easy to understand why lygus bugs (Lygus spp.) and alfalfa plant bugs (Adelphocoris lineolatus) are difficult to tell apart as they are closely related, belonging to the same family (Hemiptera: Heteroptera). They are similar in appearance (long narrow body) with the alfalfa bug being slightly longer. Adult lygus bugs have a distinctive triangular or “V”-shaped marking in the upper centre of the their backs and membranous wingtips. The alfalfa plant bug has a similar marking but it is less distinct. One difference between the two is that lygus bug nymphs have five black dots over their thorax and abdomen which alfalfa bug nymphs lack.

Another difference is that lygus bugs have a broader host range that includes canola, alfalfa, soybean, sunflower, strawberry and several other crops. Alfalfa bugs have a much more particular palette and are mainly found in alfalfa crops and only occasionally feed on red and yellow sweet clover or canola when alfalfa is in short supply.

For more information about these species and more tips on telling them apart, see our Insect of the Week page!

Tarnished plant bug (Lygus lineolaris) – cc-by Scott Bauer
Alfalfa plant bug (Adelphocoris lineolatus) – (c) Mike Dolinski. MikeDolinski@hotmail.com

The case of the innocuous versus the evil twin: When making pest management decisions, be sure that the suspect is actually a pest. This can be challenge since insects often mimic each other or look very similar. An insect that looks, moves and acts like a pest may in fact be a look-alike or doppelganger.

Doppelgangers may be related (e.g. same genus) or may not be related, as in the case of monarch butterflies (Danaus plexippus) and viceroys (Limenitis achrippus).  Doppelgangers are  usually relatively harmless but sometimes the doppelganger is a pest yet their behaviour, lifecycle or hosts may be different.

Correctly identifying a pest enables selection of the most accurate scouting or monitoring protocol. Identification and monitoring enables the application of economic thresholds. It also enables a producer to select and apply the most effective control option(s) including method and timing of application.  For the rest of the growing season, the Insect of the Week will feature insect crop pests and their doppelgangers.

Review previously featured insects by visiting the Insect of the Week page.

Weekly Update

Greetings!

Harvest is underway in parts of the prairies this week. Access the complete Weekly Update either as a series of Posts for Week 15 (August 16, 2018) OR a downloadable PDF version.  Also review the “Insect of the Week” for Week 15!

Questions or problems accessing the contents of this Weekly Update?  Please e-mail either Dr. Meghan Vankosky or Jennifer Otani.  Past “Weekly Updates” can be accessed on our Weekly Update page.

Subscribe to the Blog by following these three steps!

Weather synopsis

Weather synopsis – This week, weather data is unavailable due to technical difficulties so we are unable to generate several maps.  Please check webpages posted by Environment Canada for weather-related information.

Review the Weather synopsis for Week 13.

Pre-Harvest Intervals

Reminder – Pre-Harvest Interval (PHI) – Growers with late-season insect pest problems must factor in the PHI which is the minimum number of days between a pesticide application and swathing or straight combining of a crop.  

The PHI recommends sufficient time for a pesticide to break down and a PHI-value is both crop- and pesticide-specific.  Adhering to the PHI is important for a number of health-related reasons but also because Canada’s export customers strictly regulate and test for the presence of trace residues of pesticides.

An excellent summary of PHI for various pesticides in their various crops was posted by Saskatchewan Agriculture’s Danielle Stephens in 2016 within their Crop Production News.

In 2013, the Canola Council of Canada created and circulated their “Spray to Swath Interval Calculator” to help canola growers accurately estimate their PHI.  Other PHI are described in your provincial crop protection guides and remember that specific crop x pesticide combinations will mean different PHIs.  

Finally, work towards “Keeping It Clean” so your grain is ready for export!  More information about PHI and Maximum Residue Limits (MRL) is available on the Keeping It Clean site. 

Bertha armyworm

Bertha armyworm (Lepidoptera: Mamestra configurata– Pheromone trapping across the prairies is almost complete for the 2018 growing season but now it is important to scout for larvae feeding on leaves and developing pods!

Review your province’s 2018 bertha armyworm pheromone trapping results towards the end of this Post.

Monitoring:

  • Larval sampling should commence once the adult moths are noted. 
  • Sample at least three locations, a minimum of 50 m apart. 
  • At each location, mark an area of 1 m2 and beat the plants growing within that area to dislodge the larvae. 
  • Count them and compare the average against the values in the economic threshold table below:  

Scouting tips:

  • Some bertha armyworm larvae remain green or pale brown throughout their larval life. 
  • Large larvae may drop off the plants and curl up when disturbed, a defensive behavior typical of cutworms and armyworms. 
  • Young larvae chew irregular holes in leaves, but normally cause little damage. The fifth and sixth instar stages cause the most damage by defoliation and seed pod consumption. Crop losses due to pod feeding will be most severe if there are few leaves. 
  • Larvae eat the outer green layer of the stems and pods exposing the white tissue. 
  • At maturity, in late summer or early fall, larvae burrow into the ground and form pupae.

Albertans can access the online reporting map (screenshot below retrieved 14Aug2018 for reference):

Saskatchewan growers can check the 2018 bertha armyworm map (screenshot below retrieved 01Aug2018 for reference):

Manitoban growers can find bertha armyworm updates in that province’s Insect and Disease Updates.  A screen shot of that summary (retrieved 01Aug2018) is pasted below:

Biological and monitoring information related to bertha armyworm in field crops is posted by the provinces of ManitobaSaskatchewanAlberta and the Prairie Pest Monitoring Network.  Also refer to the bertha armyworm pages within the new “Field Crop and Forage Pests and their Natural Enemies in Western Canada: Identification and management field guide” – both English-enhanced or French-enhanced versions are available.

Lygus in canola

Lygus bugs (Lygus spp.) – The economic threshold for Lygus in canola is applied at late flower and early pod stages.  

Adult L. lineolaris (5-6 mm long) (photo: AAFC-Saskatoon).
Fifth instar lygus bug nymph (3-4 mm long) (photo:  AAFC-Saskatoon).

Damage: Lygus bugs have piercing-sucking mouthparts and physically damage the plant by puncturing the tissue and sucking plant juices. The plants also react to the toxic saliva that the insects inject when they feed. Lygus bug infestations can cause alfalfa to have short stem internodes, excessive branching, and small, distorted leaves. They feed on buds and blossoms and cause them to drop. They also puncture seed pods and feed on the developing seeds causing them to turn brown and shrivel.

Scouting tips to keep in mind:

Begin monitoring canola when it bolts and continue until seeds within the pods are firm. Since adults can move into canola from alfalfa, check lygus bug numbers in canola when nearby alfalfa crops are cut.

Sample the crop for lygus bugs on a sunny day when the temperature is above 20°C and the crop canopy is dry. With a standard insect net (38 cm diameter), take ten 180° sweeps. Count the number of lygus bugs in the net.

Sampling becomes more representative IF repeated at multiple spots within a field.  For lygus bug monitoring, sampling is most accurate when repeated at a total of 15 spots within the field.  Samples can be taken along or near the field margins. Calculate the cumulative total number of lygus bugs and then consult the sequential sampling chart (Figure C). 

If the total number is below the lower threshold line, no treatment is needed. If the total is below the upper threshold line, take more samples. If the total is on or above the upper threshold line, calculate the average number of lygus bugs per 10-sweep sample and consult the economic threshold table.

Sequential sampling for lygus bugs at late flowering stage in canola.

The economic threshold for lygus bugs in canola covers the end of the flowering (Table 1) and the early pod ripening stages (Table 2). Once the seeds have ripened to yellow or brown, the cost of controlling lygus bugs may exceed the damage they will cause prior to harvest, so insecticide application is not warranted.

Consider the estimated cost of spraying and expected return prior to making a decision to treat a crop. 

Remember that insecticide applications at bud stage in canola have not been proven to result in an economic benefit in production.  The exception to this is in the Peace River region where early, dry springs and unusually high densities of lygus bug adults can occasionally occur at bud stage.  In this situation, high numbers of lygus bugs feeding on moisture-stressed canola at bud stage is suspected to result in delay of flowering so producers in that region must monitor in fields that fail to flower as expected.

Table 1.  Economic thresholds for lygus bugs in canola at late flowering and early pod stages (Wise and Lamb 1998).

1 Canola crop stage estimated using Harper and Berkenkamp 1975).
2 Economic thresholds are based on an assumed loss of 0.1235 bu/ac per lygus bug caught in 10 sweeps (Wise and Lamb. 1998. The Canadian Entomologist. 130: 825-836).

Table 2.  Economic thresholds for lygus bugs in canola at pod stage (Wise and Lamb 1998).

 3 Economic thresholds are based on an assumed loss of 0.0882 bu/ac per lygus bug caught in 10 sweeps (Wise and Lamb. 1998. The Canadian Entomologist. 130: 825-836).

Biological and monitoring information related to Lygus in field crops is posted by the provinces of Manitoba or Alberta fact sheets or the Prairie Pest Monitoring Network’s monitoring protocol.  Also refer to the Lygus pages within the new “Field Crop and Forage Pests and their Natural Enemies in Western Canada: Identification and management field guide” – both English-enhanced or French-enhanced versions are available.

Thrips

Thrips in canola (Thynsanoptera) – While scouting at this time of year, curled canola pods may be encountered.  The culprits are quite possibly thrips.

Thrips damage observed in canola in the northeast of Saskatchewan in July 2016 (Photo: AAFC-Saskatoon, Olfert 2016).

Damage: Flower thrips (Thysanoptera) are pests of a broad range of plants including cereals and broadleaved crops such as canola. Thrips are minute, slender-bodied insects with rasping-sucking mouthparts and feed by rasping the surface of canola buds and sucking up plant fluids. 

Biology: Thrips have six life stages: egg, two larval stages, a prepupal and pupal stage and an adult. Both adults and nymphs cause damage by feeding on the flower and buds. Limited surveys in 1999 in Saskatchewan and Alberta indicated that the predominant species were Frankliniella tritici (flower thrip) followed by Thrips tabaci (onion thrip) and T. vulgatissimus (no common name).

In canola, pods damaged by thrips are often curled and tend to drop prematurely.  Some species, such as T. vulgatissimus have been credited with contributing to pollination.

Curled pods of canola caused by thrips feeding damage (Photos: AAFC-Saskatoon, Olfert et al. 1998)

Read more about thrips in canola by accessing this article by Olfert et al. 1998). 

Flea beetles

Flea Beetles (Chrysomelidae: Phyllotreta species) – By early pod stages in canola, newly eclosed adult flea beetles begin to emerge from the soil.  These individuals typically feed then move away from canola fields to locate overwintering habitats.  

Normally, it can be difficult to locate these newly emerged adults but every few years they are easily observed among canola pods.  These adults can feed on upper leaves and nip at the exterior of canola pods but are typically observed in low densities – too low to cause economic damage.  Even so, be watchful – areas with high numbers of flea beetles late in the growing season are worthwhile to scout early in 2019.  

Remember – the Action Threshold for flea beetles on canola is 25% of COTYLEDON LEAF AREA consumed.  

Normally, it is NOT recommended to apply foliar insecticides for flea beetles in canola during the pod stages for the following reasons:

  • Flea beetles are very mobile at this point in the season,
  • Canola canopy is very thick,
  • Growers must be cautious about pre-harvest intervals,
  • PLUS, little is understood about overwintering survival of this pest!

Reminder – Earlier this season, the Insect of the Week featured flea beetles!

Refer to the flea beetle page from the “Field Crop and Forage Pests and their Natural Enemies in Western Canada: Identification and management field guide” as an English-enhanced or French-enhanced version.

Ladybird beetles

Reminder – While scouting, you may encounter these fascinating organisms…..

Figure 1. Ladybird beetle larva (photo credit: AAFC-Beaverlodge)
Figure 2. Ladybird beetle pupa (Left) and larva (Right) (photo credit: AAFC-Beaverlodge)
Figure 3. Ladybird beetle pupa (photo credit: AAFC-Beaverlodge)
Figure 4. Ladybird beetle (Coccinella septempunctata) (photo credit: AAFC-Beaverlodge)
Figure 5. Aphids nestled on wheat head (photo credit: AAFC-Beaverlodge)
Figure 6. An aphid “mummy” adhered to a wheat awn.  Mummy is the aphid host converted to enclose a soon-to-emerge parasitoid wasp (photo credit: AAFC-Beaverlodge)

Ladybird beetle larvae (Fig. 1-2), pupae (Fig. 2-3), and adults (Fig. 4) can all be found in fields at this time of year.  Take a look at the various stages and the many patterns of native and introduced species to recognize these as Field Heroes!  Ladybird beetles are categorized as general predators and will feed on several species of arthropods but are partial to aphids (Fig. 5).  

Harvest Sample Program

The Canadian Grain Commission is ready and willing to grade grain samples harvested in 2018.  Samples are accepted up to November but send samples as soon a harvest is complete.

This is a FREE opportunity for growers to gain unofficial insight into the quality of their grain and to obtain valuable dockage information and details associated with damage or quality issues.  The data collected also helps Canada market its grain to the world!

More information on the Harvest Sample Program is available at the Canadian Grain Commission’s website where growers can register online to receive a kit to submit their grain.  

In exchange for your samples, the CGC assesses and provides the following unofficial results FOR FREE:

  • dockage assessment on canola
  • unofficial grade
  • protein content on barley, beans, chick peas, lentils, oats, peas and wheat
  • oil, protein and chlorophyll content for canola
  • oil and protein content and iodine value for flaxseed
  • oil and protein for mustard seed and soybean
  • NEW for 2018-19: Participants will receive Falling Number and deoxynivalenol (DON) results for their wheat samples at no cost. This enhancement to the Harvest Sample Program is the first initiative to be funded by the Canadian Grain Commission’s accumulated surplus.

Many producers find having both grade and quality information on their samples before delivering their grain to be helpful.

Stored Product Pests

The Canadian Grain Commission’s website has an online key to stored product pests.  Growers managing grain storage can find an online identification tool for stored product pests (e.g., Rusty grain beetleRed flour beetleConfused flour beetleSaw-toothed grain beetle, and more).  The online tool features excellent diagnostic photos.  A screen shot of the webpage is included below for reference.

Provincial Insect Pest Reports

Provincial entomologists provide insect pest updates throughout the growing season so we link to their most recent information: 

Manitoba‘s Insect and Disease Updates for 2018 can be accessed here. Issue #11 (posted August 8, 2018) includes initial reports of very low levels of soybean aphids and reports of bertha armyworm in canola fields in western Manitoba yet few fields exceeding economic levels. Agronomists in southwest Manitoba reported “melting” bertha armyworm larvae-read more to learn how insect-specific viruses are at work in fields! Finally, a reminder that the annual grasshopper survey is underway in August.

Saskatchewan‘s Crop Production News for 2018 is posted with Issue #6 now available. This issue informs growers that Ministry staff will be in fields conducting surveys. A reminder to manage pre-harvest intervals plus read the article describing disease and insect culprits associated with white heads in cereals.

Alberta Agriculture and Forestry’s Call of the Land regularly includes insect pest updates from Scott Meers. The most recent Call of the Land (posted August 9, 2018) includes reports of the bertha armyworm in Birch Hills county, the expected appearance of red turnip beetles which feed, mate and lay eggs at this point in the growing season, relatively low numbers of diamondback moths but a reminder to scout in canola at early pod stages, and peculiar behaviours of parasitized ladybird beetles and grasshoppers.

Crop reports

The following crop reports are also available:

Crop reports are produced by:

Previous Posts

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

Abundant parasitoids in canola – Week 10 
Alfalfa weevil – Week 6
Aphid App – Week 12

Cabbage seedpod weevil – Week 12 
Cabbage root maggot – Week 11 
Cereal aphid manager (CAM) – Week 2
Cereal leaf beetle – Week 13
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

Grasshopper simulation model output – Week 13

Monarch migration – Week 8

Pea leaf weevil – Week 13

PMRA Pesticide Label Mobile App – Week 4

Scouting charts (canola and flax) – Week 3

Ticks and Lyme Disease – Week 4

Weather synopsis – Week 13
Weather radar – Week 3
West nile virus risk – Week 13
Wheat midge – Week 12

White grubs in fields – Week 8

Wind trajectories – Week 6
Wireworm distribution maps – Week 6

Insect of the Week – Twospotted spider mite (Acarina: Tetranychus)

This week’s Insect of the Week is the twospotted spider mite. This tiny mite is 0.5 mm long and has eight legs. It has a greenish, yellowish to orange oval body with two dark spots on its abdomen. To the unaided eye, it looks like a small speck. they feed on corn, soybean, dry beans, alfalfa, vegetables and fruit.

These mites overwinter in protected sites as eggs, immatures or adults depending on food hosts and habitat. Immatures and adults move to emerging plant hosts in the spring. They create webbing on the underside of leaves where they puncture cells to feed on cell contents. This feeding causes stippling, yellowing or browning of the leaves. Leaves may dry and drop which can further reduce crop yields.

Infestations start at the field edge and move inwards. Extended hot, dry conditions favour rapid population build up and exacerbate feeding injury.

For more information on the twospotted spider mite, check out our Insect of the Week page!

Twospotted spider mite – adult closeup
David Cappaert, Michigan State University, Bugwood.org
Twospotted spider mite – stippling damage on bean
Whitney Cranshaw, Colorado State University, Bugwood.org

Weekly Update – Greetings!

Greetings!

Please access the Weekly Update for August 10, 2017 (Week 15)  as only a downloadable PDF.   


Questions or problems accessing the contents of this Weekly Update?  Please e-mail either Dr. Owen Olfert or Jennifer Otani.  Past “Weekly Updates” can be accessed on our Weekly Update page.

Subscribe to the Blog by following these three steps!

Weekly Update

Greetings!

A downloadable PDF version of the complete Weekly Update for Week 15 (August 10, 2016) can be accessed here.  

This edition includes the “Insect of the Week” featuring beneficial arthropods in 2016!

Subscribe to the Blog by following the instructions posted here!  You can receive automatic updates in your inbox through the growing season.



Questions or problems accessing the contents of this Weekly Update?  Please e-mail either Dr. Owen Olfert or Jennifer Otani.  Past “Weekly Updates” are very kindly archived to the Western Forum website by webmaster, Dr. Kelly Turkington.  

Weekly Update – Weather Synopsis

Weather synopsis – The average temperature over the past seven days (August 1-7, 2016) was approximately 1°C cooler than Long Term Normal (LTN).




Across the prairies the 7 Day Average Cumulative Rainfall was well above average (August 1-7, 2016)


The average 30 day temperature for July 8 to August 7 was similar LTN and rainfall was 50% greater than LTN (average across the prairies).

The average growing season temperature (April 1 – August 7) has been less than 1°C warmer than normal


Growing season rainfall has been approximately 27% above average.



The map below is the modelled soil moisture map for the prairies (up to August 7, 2016)



The map below reflects the 7 Day cumulative precipitation map (August 2 – August 8, 2016)


7 Day Accumulated Precip Aug 2-8.JPG

While the map below summarizes the cumulative precipitation for the growing season (April 1 – August 8, 2016).

Growing Season Accumulated Precip Apr 1-Aug 8.JPG
The updated growing degree day map (GDD) (Base 5ºC, March 1 – August 7, 2016) is below:


GDD Base 5 Aug 7

While the growing degree day map (GDD) (Base 10ºC, March 1 – August 7, 2016) is below:

GDD Base 10 Aug 7

The map below shows the Lowest Temperatures the Past 7 Days (August 2 – August 8, 2016) across the prairies:

7 Days Lowest Temp Aug 2-8.JPG
The map below shows the Highest Temperatures the Past 7 Days (August 2 – August 8, 2016):


7 Days Highest Temp Aug 2-8.JPG

Weekly Update – Pre-Harvest Intervals (PHI)

Pre-Harvest Interval (PHI) – Growers with late-season insect pest problems will need to remember to factor in the PHI which is the minimum number of days between a pesticide application and swathing or straight combining of a crop.  

The PHI recommends sufficient time for a pesticide to break down and a PHI-value is both crop- and pesticide-specific.  Adhering to the PHI is important for a number of health-related reasons but also because Canada’s export customers strictly regulate and test for the presence of trace residues of pesticides.

An excellent summary of PHI for various pesticides in their various crops was posted by Saskatchewan Agriculture this week within their Crop Production News.


In 2013, the Canola Council of Canada created and circulated their “Spray to Swath Interval Calculator” which was intended to help canola growers accurately estimate their PHI.  Other PHI are described in your provincial crop protection guides and remember that specific crop x pesticide combinations will mean different PHIs.  More information about PHI and Maximum Residue Limits (MRL) is available on the Canola Council of Canada’s website.

Weekly Update – Lygus in canola

Lygus bugs (Lygus spp.) – Reminder – The economic threshold for Lygus in canola is applied at late flower and early pod stages.  

Adult L. lineolaris (5-6 mm long) (photo: AAFC-Saskatoon).

Fifth instar lygus bug nymph (3-4 mm long) (photo:  AAFC-Saskatoon).


Damage: Lygus bugs have piercing-sucking mouthparts and physically damage the plant by puncturing the tissue and sucking plant juices. The plants also react to the toxic saliva that the insects inject when they feed. Lygus bug infestations can cause alfalfa to have short stem internodes, excessive branching, and small, distorted leaves. They feed on buds and blossoms and cause them to drop. They also puncture seed pods and feed on the developing seeds causing them to turn brown and shrivel.

Begin monitoring canola when it bolts and continue until seeds within the pods are firm. Since adults can move into canola from alfalfa, check lygus bug numbers in canola when nearby alfalfa crops are cut.

Sample the crop for lygus bugs on a sunny day when the temperature is above 20°C and the crop canopy is dry. With a standard insect net (38 cm diameter), take ten 180° sweeps. Count the number of lygus bugs in the net.

Repeat the sampling in another 14 locations. Samples can be taken along or near the field margins. Calculate the cumulative total number of lygus bugs and then consult the sequential sampling chart (Figure C). If the total number is below the lower threshold line, no treatment is needed. If the total is below the upper threshold line, take more samples. If the total is on or above the upper threshold line, calculate the average number of lygus bugs per 10-sweep sample and consult the economic threshold table.

Sequential sampling for lygus bugs at late flowering stage in canola.


The economic threshold for lygus bugs in canola covers the end of the flowering (Table 1) and the early pod ripening stages (Table 2). Once the seeds have ripened to yellow or brown, the cost of controlling lygus bugs may exceed the damage they will cause prior to harvest, so insecticide application is not warranted.

Consider the estimated cost of spraying and expected return prior to making a decision to treat a crop. 

Remember that insecticide applications at bud stage in canola have not been proven to result in an economic benefit in production.  The exception to this is in the Peace River region where early, dry springs and unusually high densities of lygus bug adults can occasionally occur at bud stage.  In this situation, high numbers of lygus bugs feeding on moisture-stressed canola at bud stage is suspected to result in delay of flowering so producers in that region must monitor in fields that fail to flower as expected.


Table 1.  Economic thresholds for lygus bugs in canola at late flowering and early pod stages (Wise and Lamb 1998).

1 Canola crop stage estimated using Harper and Berkenkamp 1975).
2 Economic thresholds are based on an assumed loss of 0.1235 bu/ac per lygus bug caught in 10 sweeps (Wise and Lamb. 1998. The Canadian Entomologist. 130: 825-836).


Table 2.  Economic thresholds for lygus bugs in canola at pod stage (Wise and Lamb 1998).

 3 Economic thresholds are based on an assumed loss of 0.0882 bu/ac per lygus bug caught in 10 sweeps (Wise and Lamb. 1998. The Canadian Entomologist. 130: 825-836).


Biological and monitoring information related to Lygus in field crops is posted by the provinces of Manitoba or Alberta fact sheets or the Prairie Pest Monitoring Network’s monitoring protocol.  Also refer to the Lygus pages within the new “Field Crop and Forage Pests and their Natural Enemies in Western Canada: Identification and management field guide” – both English-enhanced or French-enhanced versions are available.

Weekly Update – Swede midge

Swede midge (Contarinia nasturtii) The Swede midge bioclimate model was run for Melfort for 2015 and 2016 (April 1 – August 7). For 2015, model output indicated that the 2015 growing season would have resulted in two generations by the first week in August (first graph below).  For 2016, model output indicated that there has been potential for four generations in the 2016 growing season (second graph below). The extra generations in 2016 are explained by timing of rainfall. Adult emergence is delayed until a) the required number of degree-days are achieved and b) after at least 10 mm of rain has occurred (over a 7 day period). In 2015, low rainfall during April and May resulted in delayed emergence with first adults emerging in early June. A dry period in late June/early July was predicted to delay adult emergence until mid-July.  In 2016 May rainfall was predicted to result in adult emergence occurring during the second week of May and subsequent emergence in mid-June, mid-July and early August. 


Weekly Update – Grasshoppers

Grasshoppers (Acrididae) – Across the prairies the model indicates that 80% of the population should be in the adult stage. This is approximately 10% greater than average. Oviposition is predicted to be well underway with oviposition being the most advanced in MB and SE SK.

Msang Oviposition.jpg
The following graph shows predicted grasshopper development at Saskatoon for August 7, 2016


Cabbage seedpod weevil

Cabbage seedpod weevil (Ceutorhynchus obstrictus) –  Reminder – There is one generation of CSPW per year and the overwintering stage is the adult which is an ash-grey weevil measuring 3-4mm long (Refer to lower left photo).  Adults typically overwinter in soil beneath leaf litter within shelter belts and roadside ditches.

Monitoring:  
 ● Begin sampling when the crop first enters the bud stage and continue through the flowering. 
 ● Sweep-net samples should be taken at ten locations within the field with ten 180° sweeps per location.  
 ● Count the number of weevils at each location. Samples should be taken in the field perimeter as well as throughout the field.  
 ● Adults will invade fields from the margins and if infestations are high in the borders, application of an insecticide to the field margins may be effective in reducing the population to levels below which economic injury will occur.  
 ● An insecticide application is recommended when three to four weevils per sweep are collected and has been shown to be the most effective when canola is in the 10 to 20% bloom stage (2-4 days after flowering starts). 
 ● Consider making insecticide applications late in the day to reduce the impact on pollinators.  Whenever possible, provide advanced warning of intended insecticide applications to commercial beekeepers operating in the vicinity to help protect foraging pollinators.  
 ● High numbers of adults in the fall may indicate the potential for economic infestations the following spring.

Damage: Adult feeding damage to buds is more evident in dry years when canola is unable to compensate for bud loss.  Adults mate following a pollen meal then the female will deposit a single egg through the wall of a developing pod or adjacent to a developing seed within the pod (refer to lower right photo).  Eggs are oval and an opaque white, each measuring ~1mm long.  Typically a single egg is laid per pod although, when CSPW densities are high, two or more eggs may be laid per pod.


There are four larval instar stages of the CSPW and each stage is white and grub-like in appearance ranging up to 5-6mm in length (refer to lower left photo).  The first instar larva feeds on the cuticle on the outside of the pod while the second instar larva bores into the pod, feeding on the developing seeds.  A single larva consumes about 5 canola seeds.  The mature larva chews a small, circular exit hole from which it drops to the soil surface and pupation takes place in the soil within an earthen cell.  Approximately 10 days later, the new adult emerges to feed on maturing canola pods.  Later in the season these new adults migrate to overwintering sites beyond the field.


Please find additional detailed information for CSPW in fact sheets posted by Alberta Agriculture and ForestrySaskatchewan Agriculture, or the Prairie Pest Monitoring Network.

Also watch provincial reports for updates on surveying underway now.  Alberta Agriculture & Forestry has released a new live CSPW map and online reporting tool for growers.

Weekly Update – West Nile Virus and Culex tarsalis

West Nile Virus Risk –  The regions most advanced in degree-day accumulations for Culex tarsalis, the vector for West Nile Virus, are shown in the map below.  As of August 7, 2016areas highlighted in yellow, orange, or red on the map below have accumulated sufficient heat for C. tarsalis to fly so wear your DEET to stay protected!

GDD Base 14.3 Aug 7


The Public Health Agency of Canada posts information related to West Nile Virus in Canada.  The map of clinical cases of West Nile Virus in Canada in 2016 is posted (as of July 23, 2016) while a screen shot is provided below (retrieved August 10, 2016).


WN Cases Canada.jpg

The Canadian Wildlife Health Cooperative compiles and posts information related to their disease surveillance for West Nile Virus.  As of August 3, 2016, 27 birds were submitted for testing yet none have tested positive for West Nile virus. 

Provincial Insect Pest Reports

Provincial entomologists provide insect pest updates throughout the growing season so we have attempted to link to their most recent information: 


Manitoba’s Insect and Disease Update which includes lygus in canola, grasshopper monitoring, and a few sites showing moderate risk levels for bertha armyworm based on pheromone trap interceptions (August 5, 2016, prepared by John Gavloski and Pratisara Bajracharya).

Saskatchewan’s Crop Production News includes pre-harvest intervals (PHI) for a long list of field crop pesticides in Issue 6prepared by Danielle Stephens.  As the report notes, “all pesticides have a PHI” specific for product and crop type.  The PHI prevents crops exceeding Maximum Residue Levels (MRL) that will affect the quality of seed in terms of export.

Watch for Alberta Agriculture and Forestry’s Call of the Land for updates from Scott Meers  who recently provided an update (posted on August 4, 2016).

Weekly Update – Crop reports

Crop reports are produced by:

– Manitoba Agriculture, Rural Development (August 8, 2016).
– Saskatchewan Agriculture Crop Report (August 2, 2016) which is also posted in a printer-friendly version.

– Alberta Agriculture and Forestry (for August 2, 2016).

This week, the USDA’s Crop Progress Report (posted August 1, 2016) which includes harvest and condition ratings for winter wheat, spring wheat, oat, barley, plus range and pasture conditions is available. 

The USDA also produces a World Agricultural Production Report (July 2016) which estimates production across the globe for corn, cotton, rapeseed, and wheat but also includes tabular data for other grains.

Weekly Update – Time of Swathing for Canola

The Canola Council of Canada created a guide to help growers estimate swathing time in canola.  A screen shot of the downloadable Canola Swathing Guide has been included below for reference.

Weekly Update – Harvest Sample Program

The Canadian Grain Commission is ready and willing to grade grain samples harvested in 2016.  Samples are accepted up to November but send samples as soon a harvest is complete.

This is a FREE opportunity for growers to gain unofficial insight into the quality of their grain and to obtain valuable dockage information and details associated with damage or quality issues.  The data collected also helps Canada market its grain to the world!

More information on the Harvest Sample Program is available at the Canadian Grain Commission’s website where growers can register online to receive a kit to submit their grain.  


In exchange for your samples, the CGC assesses and provides the following unofficial results FOR FREE:
  • dockage assessment on canola
  • unofficial grade
  • protein content on barley, beans, chick peas, lentils, oats, peas and wheat
  • oil, protein and chlorophyll content for canola
  • oil and protein content and iodine value for flaxseed
  • oil and protein for mustard seed and soybeans
Many producers find having both grade and quality information on their samples before delivering their grain to be helpful.

Weekly Update – Previous Posts

The following is a list of previous 2016 Posts – click to review:


Alfalfa weevil
Aphids in canola 

Bertha armyworm development and flight
Bertha armyworm


Cabbage root maggot
Canola scouting chart
Cereal leaf beetle
Crop protection guides
Cutworms


Diamondback moth

Environment Canada’s radar maps to follow precipitation events


Flea beetles in canola


Grasshoppers

Iceburg reports

Insects in our diet

Monarch migration

Multitude of mayflies


Pea leaf weevil monitoring

Predicted cereal leaf beetle development

Predicted lygus bug development
Predicted wheat midge development

Swede midge


Thrips in canola

Weather Synopsis (Week 12)

Wheat midge
Wind trajectories

Insect of the Week – Natural predators

Last year, the focus of the
Beneficial 
Insect of the Week was crop pests. This year,
we’re changing things up and highlighting the many natural enemies that
help you out, silently and efficiently killing off crop pests. [note: featured
Insects of the Week in 2015 are available on the
 Insect of the Week page] 
Natural enemies don’t just appear from nowhere – they rely on nearby
non-crop and (semi-)natural sites for shelter, food, overwintering sites and
alternate hosts for when crop pests are either not present or in low numbers.
How you manage these sites can have a huge impact on natural enemies’ capacity
to supress pests when you need them to. These same sites are also essential
habitats for pollinators, important for maximizing yield of non-cereal seed
crops (e.g. oil seed crop). A recent publication, ‘Agricultural practices that
promote crop pest suppression by natural predators’, describes the role of
non-crop areas and management practices to nurture natural enemy populations.
Go to the Insect of the Week page for download links for
this publication. There you will also find more information about natural
enemies, the pests they control and details about important crop and forage
pest insects by downloading the new Field Crop and Forage Pests and their
Natural Enemies in Western Canada – Identification and Management Field Guide.



Weekly Update

Prairie Pest Monitoring Network Weekly Updates – August 12, 2015


Otani, Giffen, Svendsen, Olfert


  1. Greetings!  An HTML and PDF version of this Weekly Update can be accessed here.  


  1. Weather synopsis – The following weather maps were retrieved from AAFC’s Drought Watch website.  The map below shows the Highest Temperatures the Past 7 Days (July 29-August 10, 2015) across the prairies:

The map below shows the Accumulated Precipitation the past 7 days (i.e., July 29-August 10, 2015):
While the map below reflects the Accumulated Precipitation for the Growing Season (i.e., April 1-August 10, 2015):
The map below reflects the Percent of Normal Precipitation for the Growing Season (i.e., April 1-August 10, 2015) for comparison:
The updated growing degree day (GDD) (Base 5ºC, March 1 – August 9, 2015) map is below:

While the growing degree day (GDD) (Base 10ºC, March 1 – August 9, 2015) map is included below:

  1. Pre-Harvest Interval (PHI) – Growers is late-season insect pest problems will need to remember to factor in the PHI which is the minimum number of days between a pesticide application and swathing or straight combining of a crop.  The PHI recommends sufficient time for a pesticide to break down and a PHI-value is both crop- and pesticide-specific.  Adhering to the PHI is important for a number of health-related reasons but also because Canada’s export customers of canola strictly regulate and test for the presence of trace residues of pesticides.
In 2013, the Canola Council of Canada created and circulated their “Spray to Swath Interval Calculator” which was intended to help canola growers accurately estimate their PHI.  Other PHI are described in your provincial crop protection guides and remember that specific crop x pesticide combinations will mean different PHIs.  A screen shot of the webpage is included below for your reference.
  1. Bertha armyworm (Mamestra configurata) –     In-field monitoring will focus on searching for Bertha armyworm larvae which will feed on leaves but also upon newly developing pods.  Take care to examine the whole plant when scouting.  Watch for the following life stages:
Reminder:  Some bertha armyworm larvae remain green or pale brown throughout their larval life. Large larvae may drop off the plants and curl up when disturbed, a defensive behavior typical of cutworms and armyworms. Young larvae chew irregular holes in leaves, but normally cause little damage. The fifth and sixth instars cause the most damage by defoliation and seed pod consumption. Crop losses due to pod feeding will be most severe if there are few leaves. Larvae eat the outer green layer of the stems and pods exposing the white tissue. At maturity, in late summer or early fall, larvae burrow into the ground and form pupae.
Monitoring:
Sample at least three locations (a minimum of 50 m apart) within a field for larvae.  At each location, mark an area of 1 m2 and beat the plants growing within that area to dislodge the larvae. Count them and compare the average against the values in the economic threshold table below:  
Table 1.  Economic thresholds for Bertha armyworm in canola (courtesy Manitoba Agriculture, Food and Rural Initiatives).
Expected Seed Value – $ / bushel*
Spraying cost –
$ / acre
6
7
8
9
10
11
12
13
14
15
16
Number of Larvae / metre2 *
7
20
17
15
13
12
11
10
9
9
8
8
8
23
20
17
15
14
13
11
11
10
9
9
9
26
22
19
17
16
14
13
12
11
10
10
10
29
25
22
19
17
16
14
13
12
11
11
11
32
27
24
21
19
17
16
15
14
13
12
12
34
30
26
23
21
19
17
16
15
14
13
13
37
32
28
25
22
20
19
17
16
15
14
14
40
35
31
27
24
22
20
19
17
16
15
15
43
37
32
29
26
23
22
20
19
17
16
* Economic thresholds for bertha armyworm are based on an assumed yield loss of 0.058 bu/acre for each larva/metre2 (Bracken and Bucher. 1977. Journal of Economic Entomology. 70: 701-705).
  1. Diamondback Moth (Plutella xylostella) – In-field monitoring for DBM larvae should continue this week.
Larval Monitoring:
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 dislodged from the plant. Repeat this procedure at least in five locations in the field to get an accurate count.  
Remember, parasitoid wasps attacking DBM larvae (Refer to photo below) are already present in fields.  Use the economic thresholds to preserve these beneficial wasps by NOT applying insecticide until DBM larval densities exceed the threshold.
Diamondback larva (upper left) and pupal silk cocoon (upper right), Diadegma insulare adult and early instar Diamondback moth larvae on canola leaf (lower left) and D. insulare pupae (N=2) within Diamondback moth pupal silk cocoons (lower right).
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).
  1. Swede midge (Contarinia nasturtii) – Thank you to Dr. Lars Andreassen who provided the following update for swede midge monitoring in Saskatchewan for 2015.  Very low swede midge numbers have been intercepted at pheromone trap monitoring sites across the prairies but these results are not surprising given the drought conditions.  In-field surveying performed by Andreassen et al. (AAFC-Saskatoon) are mapped below for 2015.  Their findings show consistent swede midge populations (larvae and damage symptoms) in northeast Saskatchewan in 2015.  Note there are new records of larvae and swede midge damage at sites surrounding Lloydminster up against the Alberta border in 2015.
Reminder – Swede midge scouting tips for in-field monitoring:
  • Watch for unusual plant structures and plant discolourations then follow-up by closely scrutinizing the plant for larvae (Refer to Figure below for larvae among the anthers).
  • The growing tip may become distorted and produce several growing tips or none at all, young leaves may become swollen, crinkled or crumpled and brown scarring caused by larval feeding may be seen on the leaf petioles and stems.
  • Flowers may fail to open.
  • Young plants that show unusual growth habits should be examined carefully for damage and larvae, especially if the sticky liners have many flies resembling midges (swede midges are about the size of orange blossom wheat midge but are not orange).
  • Larvae can be seen with a hand lens.
  • Refer to the latest Canola Watch for a swede midge update from Dr. Julie Soroka.

In 2014, Canola School posted a swede midge update entitled “ Swede midge a pest on the rise”, featuring Dr. Julie Soroka (AAFC-Saskatoon).  The Ontario Canola Growers post swede midge information here.  Dr. Rebecca Hallett has posted a very helpful swede midge identification guide for those performing in-field monitoring and pheromone trapping.  Finally, canola management recommendations for swede midge in Ontario are posted by Rebecca Hallett and Brian Hall.

  1. Cabbage seedpod weevil (Ceutorhynchus obstrictus) –  There is one generation of CSPW per year and the overwintering stage is the adult which is an ash-grey weevil measuring 3-4mm long (Refer to lower left photo).  Adults typically overwinter in soil beneath leaf litter within shelter belts and roadside ditches.  They emerge from overwintering in the spring as soil temperatures warm to ~15°C.  CSPW utilize several flowering hosts including wild mustard, flixweed, hoary cress, stinkweed and volunteer canola.  CSPW move to canola during the bud to early flower stages and will feed on pollen and buds, causing flowers to die.  Adult feeding damage to buds is more evident in dry years when canola is unable to compensate for bud loss.  Adults mate following a pollen meal then the female will deposit a single egg through the wall of a developing pod or adjacent to a developing seed within the pod (refer to lower right photo).  Eggs are oval and an opaque white, each measuring ~1mm long.  Typically a single egg is laid per pod although, when CSPW densities are high, two or more eggs may be laid per pod.
There are four larval instar stages of the CSPW and each stage is white and grub-like in appearance ranging up to 5-6mm in length (refer to lower left photo).  The first instar larva feeds on the cuticle on the outside of the pod while the second instar larva bores into the pod, feeding on the developing seeds.  A single larva consumes about 5 canola seeds.  The mature larva chews a small, circular exit hole from which it drops to the soil surface and pupation takes place in the soil within an earthen cell.  Approximately 10 days later, the new adult emerges to feed on maturing canola pods.  Later in the season these new adults migrate to overwintering sites beyond the field.  

Monitoring:  Begin sampling when the crop first enters the bud stage and continue through the flowering. Sweep net samples should be taken at ten locations within the field with ten 180° sweeps per location. Count the number of weevils at each location. Samples should be taken in the field perimeter as well as throughout the field.  Adults will invade fields from the margins and if infestations are high in the borders, application of an insecticide to the field margins may be effective in reducing the population to levels below which economic injury will occur.  An insecticide application is recommended when three to four weevils per sweep are collected and has been shown to be the most effective when canola is in the 10 to 20% bloom stage (2-4 days after flowering starts). Consider making insecticide applications late in the day to reduce the impact on pollinators.  Whenever possible, provide advanced warning of intended insecticide applications to commercial beekeepers operating in the vicinity to help protect foraging pollinators.  High numbers of adults in the fall may indicate the potential for economic infestations the following spring. 

Please find additional detailed information for CSPW in fact sheets posted by Alberta Agriculture and Forestry, Saskatchewan Agriculture, or the Prairie Pest Monitoring Network.

  1. Lygus bugs (Lygus spp.) – The economic threshold for Lygus in canola is applied at late flower and early pod stages.  Biological and monitoring information can be linked by clicking here or you can access Manitoban, or Albertan fact sheets or the Prairie Pest Monitoring Network’s monitoring protocol.  
Adult Lygus Bug
Adult L. lineolaris (5-6 mm long) (photo: AAFC-Saskatoon).
Lygus Bug Nymph
Fifth instar lygus bug nymph (3-4 mm long) (photo:  AAFC-Saskatoon).
Damage: Lygus bugs have piercing-sucking mouthparts and physically damage the plant by puncturing the tissue and sucking plant juices. The plants also react to the toxic saliva that the insects inject when they feed. Lygus bug infestations can cause alfalfa to have short stem internodes, excessive branching, and small, distorted leaves. They feed on buds and blossoms and cause them to drop. They also puncture seed pods and feed on the developing seeds causing them to turn brown and shrivel.
Begin monitoring canola when it bolts and continue until seeds within the pods are firm. Since adults can move into canola from alfalfa, check lygus bug numbers in canola when nearby alfalfa crops are cut.
Sample the crop for lygus bugs on a sunny day when the temperature is above 20°C and the crop canopy is dry. With a standard insect net (38 cm diameter), take ten 180° sweeps. Count the number of lygus bugs in the net.
Repeat the sampling in another 14 locations. Samples can be taken along or near the field margins. Calculate the cumulative total number of lygus bugs and then consult the sequential sampling chart (Figure C). If the total number is below the lower threshold line, no treatment is needed. If the total is below the upper threshold line, take more samples. If the total is on or above the upper threshold line, calculate the average number of lygus bugs per 10-sweep sample and consult the economic threshold table.
Sequential Sampling for Lygus Bug at Late Flowering Stage
Sequential sampling for lygus bugs at late flowering stage in canola.
The economic threshold for lygus bugs in canola covers the end of the flowering (Table 1) and the early pod ripening stages (Table 2). Once the seeds have ripened to yellow or brown, the cost of controlling lygus bugs may exceed the damage they will cause prior to harvest, so insecticide application is not warranted.
Table 1.  Economic thresholds for lygus bugs in canola at late flowering and early pod stages (Wise and Lamb 1998).
1 Canola crop stage estimated using Harper and Berkenkamp 1975).
2 Economic thresholds are based on an assumed loss of 0.1235 bu/ac per lygus bug caught in 10 sweeps (Wise and Lamb. 1998. The Canadian Entomologist. 130: 825-836).
Table 2.  Economic thresholds for lygus bugs in canola at early pod stage (Wise and Lamb 1998).
3 Economic thresholds are based on an assumed loss of 0.0882 bu/ac per lygus bug caught in 10 sweeps (Wise and Lamb. 1998. The Canadian Entomologist. 130: 825-836).
  1. Time of Swathing – The Canola Council of Canada created a guide to help growers estimate swathing time in canola.  A screen shot of the downloadable guide has been included below for reference.
  1. Harvest Sample Program – The Canadian Grain Commission is ready and willing to grade grain samples harvested in 2015.  This is a FREE opportunity for growers to gain unofficial insight into the quality of their grain and to obtain valuable dockage information and details associated with damage or quality issues.  More information on the Harvest Sample Program is available at the Canadian Grain Commission’s website or growers can register online to receive a kit to submit their grain.  The following screen shot of the CGC webpage offers more details.
  1. Provincial Insect Pest Updates – The following provincial websites have their pest updates posted so click the links to access their reports:
●  Manitoba’s Insect and Disease Report  (August 4, 2015) featuring lygus bugs and a reminder for the Fall grasshopper monitoring plus how it supports the 2016 grasshopper forecast map.
●  Saskatchewan’s Insect Update (July 23, 2015) featuring descriptions of causes of white heads in wheat.
●  Alberta’s Insect Update (Call of the Land audio report of August 6, 2015) featuring lygus bugs, aphids in cereals and diamondback moths.
  1. Insect of the Week – Field Crop and Forage Pests and their Natural Enemies in Western Canada: Identification and Field Guide (2015) by Hugh Philip is a new publication from Agriculture and Agri-Food CanadaThis growing season we will post an “Insect of the Week” in the form of short excerpts from the field guide. This week features the Beet webworm.
  1. Crop Reports –  The following provincial websites now have their Crop Reports posted so click the links to find their weekly updates:
  1. West Nile Virus Risk –  The regions most advanced in degree-day accumulations for Culex tarsalis, the vector for West Nile Virus, are shown in the map below.  Areas highlighted in red on the map below will have accumulated sufficient heat for C. tarsalis to fly.
The Public Health Agency of Canada posts information related to West Nile Virus in Canada and their website is located here.  The Canadian Wildlife Health Cooperative compiles and posts information related to their disease surveillance.  As of this week, nine birds in Ontario and five birds in Quebec tested positive for West Nile-related deaths (click here to view the report).
As of August 9, 2015, adult C. tarsalis are predicted to be in flight throughout much of the prairies – apply DEET if you are active outdoors within areas highlighted red, rose or pink in the map below!!  Areas highlighted orange should be prepared with DEET!
  1. Questions or problems accessing the contents of this Weekly Update?  Please e-mail either Dr. Owen Olfert or Jennifer Otani.  Past and present “Weekly Updates” are very kindly posted to the Western Forum website by webmaster, Dr. Kelly Turkington.  Please click here to link to that webpage.
  1. Previous topics:
    1. The PPMN Blog is located at http://prairiepestmonitoring.blogspot.ca/    Subscribe to receive the most current information OR bookmark the site to visit later.
    2. Field Crop and Forage Pests and their Natural Enemies in Western Canada: Identification and management field guide – The NEW Field Guide to Support Integrated Pest Management (IPM) in Field and Forage Crops is NOW available for download from www.publications.gc.ca.   Two downloadable (~8 MB) versions of the complete field guide are available as either a  ‘Regular’ (i.e., best for printing: EnglishFrench) or ‘Enhanced’ (i.e., best for viewing electronically with active internal and external hyperlinks: English-enhancedFrench-enhanced).
    3. Wind trajectories Related to Diamondback Moth (DBM) and Aster Leafhopper Introductions – Completed for the season.  Please refer to earlier Weekly Updates for details related to backward and forward trajectories associated with air parcels moving over western Canadian locations.
    4. Flea Beetles (Chrysomelidae: Phyllotreta species) – Helpful images produced by Dr. Julie Soroka (AAFC-Saskatoon) exemplifying percent of cotyledon leaf area consumed by flea beetles are posted at Canola Watch.  
    5. Cutworms (Noctuidae) – Cutworm biology, species information, plus monitoring recommendations are available at the Prairie Pest Monitoring Network’s Cutworm Monitoring Protocol.  Also refer to these cutworm-specific fact sheets (Manitoba Agriculture and Rural Initiatives, Alberta Agriculture and Forestry).
    6. Pea Leaf Weevil (Sitona lineatus) –Link here for the Pea leaf weevil monitoring protocol which includes photos of related weevils.
    7. Crop Protection Guides – Access Saskatchewan’s Crop Production Guide,  Manitoba’s Guide to Crop Production,  Alberta’s Crop Protection or Blue Book,  or the Western Committee on Crop Pests Guidelines for the Control of Crop Pests.
    8. Canola Insect Scouting Chart – The Canola Insect Scouting Chart has been updated with hyperlinks now directing growers to downloadable pages from the NEW Field Guide!
    9. Alfalfa Weevil (Hypera postica) – Alfalfa growers are encouraged to check the Alfalfa Weevil Fact Sheet prepared by Dr. Julie Soroka (AAFC-Saskatoon).
    10. Cabbage root maggot (Delia spp.) – A summary of root maggot biology, research, and pest management recommendations for canola production was published by Soroka and Dosdall (2011).  Remember there are no registered insecticides for root maggot control in canola.
    11. Wheat midge (Sitodiplosis mosellana) –  – Additional wheat midge biology and monitoring information can be located by clicking here or by linking to provincial fact sheets (Saskatchewan Agriculture or Alberta Agriculture and Forestry).  More information related to wheat midge on the Canadian prairies was published by Elliott, Olfert, and Hartley in 2011.  
    12. Cereal Leaf Beetles (Oulema melanopus) – Reminder – Fact sheets for Cereal leaf beetle (CLB) are posted by Alberta Agriculture and Forestry, and BC Ministry of Agriculture, and the Prairie Pest Monitoring Network.  
    13. Grasshoppers (Camnulla pellucida, Melanoplus sanguinipes, M. bivittattus, M. packardii) –
Remember only five or six grasshopper species of the 80+ that occur on the prairies are regarded as crop pests.  Economic thresholds for grasshoppers are posted by Manitoba Agriculture, Saskatchewan Agriculture, Alberta Agriculture and Forestry, BC Ministry of Agriculture, and the Prairie Pest Monitoring Network.
    1. Bertha armyworm (Mamestra configurata) – Provincial fact sheets describing the biology and related pest management information for bertha armyworm are posted by Manitoba Agriculture, Food and Rural Development, Saskatchewan Agriculture, Alberta Agriculture and Forestry, or BC Ministry of Agriculture.

Insect of the Week – Beet webworm

This week’s Insect of the Week is the beet webworm (Loxostege sticticalis (Linnaeus)) (from the new Field Crop and Forage Pests and their Natural Enemies in Western Canada – Identification and Management Field Guide – download links available on the Insect of the Week page). 

(c) AAFC-AAC