Insect of the Week – Dingy cutworm

Jennifer Otani
Week 4

For many, seed isn’t even in the ground yet, but the cutworms are ready for it when it is. So the time to start scouting for cutworms is now! Even if it is too wet to seed, consider checking volunteer plants for cutworms or feeding damage. General cutworm monitoring protocols can be found on the Monitoring Protocols page. Species-specific protocols can be found in the new Cutworm Pests of Crops on the Canadian Prairies (see below for download details).

There are over 20 cutworm species that may cause economic damage to your crop, each with different feeding behaviour, preferred hosts and lifecycle. This is why species identification is so important: it helps growers understand what they are up against: determining how and when to scout, knowing whether the cutworm species is found above-ground (climbing) or below-ground, recognizing damage, choosing control options. Species also impacts the most appropriate time of day for monitoring and applying controls.

Action and economic thresholds do exist for many of the cutworm species – please use them. This will help control costs by eliminating unnecessary/un-economic sprays and reduce your impact on non-target insects – insects that include cutworm natural enemies that work in the background to control cutworm populations.

This week’s Insect of the Week is the dingy cutworm. This is an above ground climbing species. Crops are at greatest risk in the spring when partially mature larvae emerge to feed primarily on leaves. The name ‘dingy cutworm’ is generally applied to three closely related species with similar appearance and life cycles.

For more information about dingy cutworms, go to the Insect of Week page.

Dingy cutworm larva (cc John Gavioski, Manitoba Agriculture)

Remember the NEW Cutworm Field Guide is free and downloadable in 2017!

Weekly Update – Weather Synopsis

Ross Weiss, David Giffen, Owen Olfert and prairiepest_admin
Week 4

Weather synopsis – This week’s average temperatures were approximately 3°C cooler than normal (Fig. 1) and seven day precipitation accumulations were above normal.  The 30-day rainfall amounts were below average in eastern Saskatchewan and Manitoba (Fig. 2)

The map below reflects the Accumulated Precipitation for the Growing Season so far for the prairie provinces (i.e., April 1-May 24, 2017):

The map below shows the Lowest Temperatures the Past 7 Days (May 18-24, 2017) across the prairies:

Whereas the map below shows the Highest Temperatures the Past 7 Days (May 18-24, 2017):

The updated growing degree day map (GDD) (Base 5ºC, March 1 – May 22, 2017) is below:

While the growing degree day map (GDD) (Base 10ºC, March 1 – May 22, 2017) is below:

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

2017 Wind Trajectories

Ross Weiss, Owen Olfert, Serge Trudel and prairiepest_admin
Week 4

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

Reverse trajectories (RT)

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

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

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

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

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

Weekly Update – Flea beetles

Jennifer Otani
Week 4

Flea Beetles (Chrysomelidae: Phyllotreta species) – Be on the lookout for flea beetle damage resulting from feeding on canola cotyledons but also on the stem.  Two species, Phyllotreta striolata and P. cruciferae, will feed on all cruciferous plants but they can cause economic levels of damage in canola during the seedling stages.

Remember, the Action Threshold for flea beetles on canola is 25% of cotyledon leaf area consumed.  Watch for shot-hole feeding in seedling canola but also watch the growing point and stems of seedlings which are particularly vulnerable to flea beetle feeding.

Estimating flea beetle feeding damage can be challenging.  Using a visual guide to estimate damage can be helpful.  Canola Watch circulated this article but also use the two images (copied below for reference) produced by Dr. J. Soroka (AAFC-Saskatoon)  – take it scouting!

Figure 1. Canola cotyledons with various percentages of leaf area consume owing to flea beetle feeding damage (Photo: Soroka & Underwood, AAFC-Saskatoon).

Figure 2.  Percent leaf area consumed by flea beetles feeding on canola seedlings (Photo: Soroka & Underwood, AAFC-Saskatoon).

Refer to the flea beetle page from the new “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.

Weekly Update – Cutworms

Jennifer Otani
Week 4

Cutworms (Noctuidae) – NEW – Just in time for spring scouting!  A new field guide is now available to help growers scout and manage Cutworms!  Cutworm Pest of Crops is now available for free in either English or French and is featured at our new Cutworm Field Guide!  Also be sure to check the Insect of the Week throughout May – it highlights cutworms!  Be sure to read more about Dingy cutworms.

Dingy cutworm larva (cc John Gavloski, Manitoba Agriculture)

Several species of cutworms can be present in fields.  They range in colour from shiny opaque, to tan, to brownish-red with chevron patterning.  Cutworm biology, species information, plus monitoring recommendations are available in the Prairie Pest Monitoring Network’s Cutworm Monitoring Protocol.  Also refer to the Manitoba Agriculture cutworm fact sheet which includes action and economic thresholds for cutworms in several crops. 

Keep an eye on fields that are “slow” to emerge, are missing rows, include wilting or yellowing plants, have bare patches, or appear highly attractive to birds – these are areas warranting a closer look.  Plan to follow-up by walking these areas later in the day when some cutworm species move above-ground to feed.  Start to dig below the soil surface (1-5 cm deep) near the base of a symptomatic plant or the adjacent healthy plant.  If the plant is well-established, check within the crown in addition to the adjacent soil.  The culprits could be wireworms or cutworms.  

For Albertans….. If you find cutworms, please consider using the Alberta Pest Surveillance Network’s “2017 Cutworm Reporting Tool”.  The map now has reports of pale western and redbacked cutworms in central and southern Alberta so view the live 2017 cutworm map.

Remember the NEW Cutworm Field Guide is free and downloadable in 2017!

Weekly Update – Cereal leaf beetle

Ross Weiss, Owen Olfert and prairiepest_admin
Week 4

Cereal leaf beetle (Oulema melanopus) – As of May 22, 2017, the CLB model indicates that oviposition is well underway across the southern prairies. Compared to southern Alberta and Saskatchewan, populations in southern Manitoba are predicted to be delayed by approximately five days (Fig. 1). Compared to 2016, development in 2017 is approximately 1 week later. Hatch is predicted to occur in isolated areas. 

Lifecycle and Damage:
Adult: Adult cereal leaf beetles (CLB) have shiny bluish-black wing-covers (Fig. 2). The thorax and legs are light orange-brown. Females (4.9 to 5.5 mm) are slightly larger than the males (4.4 to 5 mm). Adult beetles overwinter in and along the margins of grain fields in protected places such as in straw stubble, under crop and leaf litter, and in the crevices of tree bark. They favour sites adjacent to shelter belts, deciduous and conifer forests. They emerge in the spring once temperature reaches 10-15 ºC and are active for about 6 weeks. They usually begin feeding on grasses, then move into winter cereals and later into spring cereals.  

Figure 2. Adult Oulema melanopus (~4.4-5.5 mm long).

Egg: Eggs are laid approximately 14 days following the emergence of the adults. Eggs are laid singly or in pairs along the mid vein on the upper side of the leaf and are cylindrical, measuring 0.9 mm by 0.4 mm, and yellowish in colour. Eggs darken to black just before hatching.  

Larva: The larvae hatch in about 5 days and feed for about 3 weeks, passing through 4 growth stages (instars). The head and legs are brownish-black; the body is yellowish. Larvae are usually covered with a secretion of mucus and fecal material, giving them a shiny black, wet appearance (Fig. 3).  When the larva completes its growth, it drops to the ground and pupates in the soil. 

Figure 3.  Larval stage of Oulema melanopus with characteristic feeding damage visible on leaf.

Pupa: Pupal colour varies from a bright yellow when it is first formed, to the colour of the adult just before emergence. The pupal stage lasts 2 – 3 weeks. Adult beetles emerge and feed for a couple of weeks before seeking overwintering sites. There is one generation per year.

Fact sheets for CLB are published by the province of Alberta and available from the Prairie Pest Monitoring Network. Also access the Oulema melanopus page from the new “Field crop and forage pests and their natural enemies in western Canada – Identification and management field guide”.

Weekly Update – Pea leaf weevil

Jennifer Otani, Ross Weiss, Owen Olfert and Meghan Vankosky
Week 4

Pea Leaf Weevil (Sitona lineatus– The pea leaf weevil simulation model will be used to monitor weevil development across the prairies. Weekly temperature data collected across the prairies is incorporated into the simulation model which calculates estimates of weevil development stages based on biological parameters for Sitona lineatus.

The PLW model was run for Lethbridge AB and Saskatoon SK. Meteorological data (April 1 – May 15, 2017) and climate data (May 16- June 30) were used to predict PLW phenology.  Output indicates that PLW oviposition in Lethbridge is approximately one week earlier than Saskatoon.  Reminder – Access last week’s PLW model output predictions here.

Pea leaf weevils emerge in the spring primarily by flying (at temperatures above 17ºC) or they may walk short distances. Pea leaf weevil movement into peas and faba beans is achieved primarily through flight.  Adults are slender, greyish-brown measuring approximately 5 mm in length (Fig. 1, Left).  

The pea leaf weevil resembles the sweet clover weevil (Sitona cylindricollis) but the former is distinguished by three light-coloured stripes extending length-wise down thorax and sometimes the abdomen.  All species of Sitona, including the pea leaf weevil, have a short snout.  

Figure 3.  Comparison images and descriptions of four Sitona species adults including pea leaf weevil (Left).

Adults will feed upon the leaf margins and growing points of legume seedlings (alfalfa, clover, dry beans, faba beans, peas) and produce a characteristic, scalloped (notched) edge.  Females lay 1000 to 1500 eggs in the soil either near or on developing pea or faba bean plants from May to June.

Biological and monitoring information related to pea leaf weevil in field crops is posted by the province of Alberta.  Also refer to the pea leaf weevil page within the “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.  A review of this insect was published in 2011 in Prairie Soils and Crops by Carcamo and Vankosky.

Weekly Update – Alfalfa weevil

Jennifer Otani and David Giffen
Week 4

Alfalfa Weevil (Hypera postica) – The larval stage of this weevil feeds on alfalfa leaves in a manner that characterizes the pest as a “skeletonizer”.  The green larva featuring a dorsal, white line down the length of its body has a dark brown head capsule and will grow to 9mm long.  Alfalfa growers are encouraged to check the Alfalfa Weevil Fact Sheet prepared by Dr. Julie Soroka (AAFC-Saskatoon).

Degree-day maps of base 9°C are now being produced by Soroka, Olfert, and Giffen (2016) using the Harcourt/North Dakota models.  Models predicting the development of Alfalfa weevil (Hypera postica) across the prairies are updated weekly to help growers time their in-field scouting for second-instar larvae.  Compare the following predicted development stages and degree-day values from Soroka (2015) to the map below.

This week, embryological development is greatest across south and central regions of Alberta and Saskatchewan and across southern Manitoba. Early hatch is predicted to occur in a region near Brooks AB and Regina SK and south to the USA border.

Use the figure below as a visual reference to identify alfalfa weevil larvae.  Note the white dorsal line, the tapered shape of the abdomen and the dark head capsule.

Additional information can be accessed by reviewing the Alfalfa Weevil Page extracted from the “Field crop and forage pests and their natural enemies in western Canada – Identification and management field guide” (Philip et al. 2015).  The guide is available in both a free English-enhanced or French-enhanced version.

Weekly Update – Predicted Grasshopper Development

Ross Weiss, Owen Olfert and prairiepest_admin
Week 4

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).  

As of May 22, 2017, predicted mean embryological development was 70% (66% last week); the greatest development was predicted to be across southern regions in all three provinces (similar to long term averages; Fig. 1).  

Figure 1.  Simulation model outputs mapped to predict the embryological development of Migratory grasshopper  (Melanoplus sanguinipes) eggs across the Canadian prairies as of May 15, 2017).
Model output indicates that development near Regina SK (Fig 2, Top) is slightly greater than Lethbridge AB (Fig. 2, Middle). Hatch in Lethbridge is predicted to be two weeks ahead of model predictions for Grande Prairie AB (Fig 2, Bottom). 

Figure 2. Predicted development of Migratory grasshoppers near Regina SK (Top), Lethbridge AB (Middle), and Grande Prairie AB (Bottom). 


Reminder – The Prairie Pest Monitoring Network’s 2017 Grasshopper Forecast Map can be viewed here.  

Biological and monitoring information related to grasshoppers in field crops is posted by Manitoba Agriculture, Food and Rural DevelopmentSaskatchewan AgricultureAlberta Agriculture and Forestry, the BC Ministry of Agriculture and the Prairie Pest Monitoring Network.  Also refer to the grasshopper pages within the new “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.

Weekly Update – Wheat midge

Jennifer Otani
Week 4

Wheat Midge (Sitodiplosis mosellana– Predictive modelling will be used again to help  forecast wheat midge emergence across the Canadian prairies.  The maps below predicts the geographic distribution and corresponding accumulation of heat units necessary for wheat midge to emerge from puparia developing in the soil.  

For the week of May 24, 2017, soil moisture and temperature conditions appear to be conducive for wheat midge development. The wheat midge model indicates that wheat midge larvae should be moving to the soil surface by the end of May

Reminder – Back in January, the 2017 Wheat midge forecast map was released along with the other Risk and Forecast maps. It’s posted again below for reference.

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.

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.

Weekly Update – Predicted Bertha Armyworm Development

David Giffen and prairiepest_admin
Week 4

Bertha armyworm (Lepidoptera: Mamestra configurata– This week, predicted pupal development is well underway. Average development is 36% (27% last week); average development is 37% (Fig. 1). 

Figure 1. Predicted stage of pupal development of overwintered Bertha armyworm set to emerge in 2017.

Reminder – These maps will be updated weekly to aid those who deploy and monitor this moth using pheromone traps.  The video below posted by Alberta Agriculture and Forestry’s Scott Meers describes how pheromone traps are used to monitor this important pest of canola.

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.

Provincial Insect Pest Reports

John Gavloski, Scott Meers and Scott Hartley
Week 4

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 for 2017 will be posted soon. Watch for updates prepared by John Gavloski and Pratisara Bajracharya). Reports from 2016 can be reviewed here.

Saskatchewan’s Crop Production News for 2017 will be posted soon. Watch for updates prepared by Scott Hartley and Danielle Stephens.  

Watch for Alberta Agriculture and Forestry’s Call of the Land which featured reminders and links to help growers scout for cutworms from Scott Meers (May 25, 2017) plus information related to tick surveillance and Lyme disease (May 25, 2017).

Crop reports

Jennifer Otani
Week 4

Crop reports are produced by:
• Manitoba Agriculture, Rural Development (May 24, 2017)
• Saskatchewan Agriculture Crop Report (May 16-22, 2017)
• Alberta Agriculture and Forestry Crop Report (May 16, 2017)

International reports are produced by:
• The United States Department of Agriculture’s Crop Progress Report (May 22, 2017)

Weekly Update – Monarch migration

Jennifer Otani
Week 4

We again track the migration of the Monarch butterflies as they move north by checking the 2017 Monarch Migration Map!  A screen shot of the map has been placed below as an example (retrieved 26May2017) but follow the hyperlink to check the interactive map!  They’ve migrated into southern Ontario! 

Weekly Update – Ticks and Lyme Disease

Jennifer Otani
Week 4

As the spring weather improves and people are active outdoors, remember to watch for ticks.  Blacklegged (deer) ticks are important because they can carry Lyme Disease.  Endemic and risk areas for Lyme disease have been mapped in Canada (Fig. 1).  Continued surveillance activities conducted by Health Canada and the provinces remain important and you can help by identifying / removing / submitting your ticks!

Follow the links to learn more and to submit ticks if you live in British Columbia, Alberta, Saskatchewan, Manitoba, Ontario, or Quebec.
Figure 1. Screenshot of Health Canada’s map of Lyme disease endemic and risk areas in Canada (retrieved 26May2017).