Insect of the Week – Pale western cutworm

Jennifer Otani
Week 1

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 Pale Western Cutworm. This is a below-ground feeder. Larvae hatch in late April/early May. As they feed on/tunnel through shoots as they pass through the soil, young larvae produce holes on newly-emerged shoots and furled leaves . Older larvae will sever plants just below the soil surface and may pull and eat the severed shoots underground.

For more information about Pale Western Cutworm, go to the Insect of Week page.

Pale western cutwom. cc-by-nc 3.0 Frank Peairs,
Colorado State University,

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

Weekly Update – Welcome Back!

Jennifer Otani, Owen Olfert and Erl Svendsen
Week 1

It’s Spring and the Weekly Update is back for the 2017 growing season in Blog form!

A downloadable PDF version of the complete Weekly Update for Week 1 (May 4, 2017) can be accessed here.

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 can be accessed on our Weekly Update page.

Weekly Update – Weather Synopsis

Owen Olfert, Ross Weiss and prairiepest_admin
Week 1

Weather synopsis – We begin with a synopsis of the weather situation starting with the map below which reflects the Accumulated Precipitation received during the winter (Nov 1, 2016 to Mar 31, 2017) across the prairies (Figure 1).

Figure 1. Accumulated precipitation across the Canadian prairies during the winter (November 1, 2016-March 31, 2017).

Average temperatures over the past month have been warmest across the southern prairies. April precipitation was greater across Manitoba and eastern Saskatchewan than western Saskatchewan or Alberta (Figure 2).  Compared to last year at this time, April 2017 was approximately 2°C cooler with marginally greater precipitation than last year (prairie-wide average values; Figure 3).
Figure 2. Average temperatures across the Canadian prairies the past 30 days (April 1-30, 2017).

Figure 3. Cumulative precipitation across the Canadian prairies the past 30 days (April 1-30, 2017).

The map below reflects the Highest Temperatures occurring over the past 7 days across the prairies.

The map below reflects the Lowest Temperatures occurring over the past 7 days across the prairies.

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, Serge Trudel, Owen Olfert and prairiepest_admin
Week 1

THE WEEK OF MAY 1, 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 1, 2017:

Reverse trajectories (RT)

Wind trajectories have been monitored since April 1 this year.  To date, winds have originated predominantly from the USA – Pacific Northwest (PNW).   Overall results indicate that eastern locations on the prairies have had fewer of these winds than western locations (Figure 1).  Over the last week (April 25- May 1, 2017), Lethbridge has had significantly more RT’s from the Pacific Northwest than either SK and MB sites (Figure 2).  

Figure 1. Summary of reverse trajectory wind data (PNW) for the
prairies April 1-May 1, 2017.
Figure 2. Based on results for specific locations (Brandon,
Saskatoon, Lethbridge), Lethbridge has had significantly more RT’s from the
Pacific Northwest than SK and MB.  

Forward trajectories (FT)
Forward trajectories that were predicted to cross the prairies from the southern USA and Mexico have been limited so far. There were a few isolated days of winds from Santa Maria and Imperial Valley, CA. and from Mexicali, Mexico in mid-April.

Weekly Update – Diamondback moth

Jennifer Otani
Week 1

Diamondback moth (Plutellidae: Plutella xylostella) – Pheromone traps attracting male Diamondback moths are being deployed across the prairies.  High altitude air masses are tracked by AAFC-Saskatoon Staff (forward and backward trajectories).  These wind events have the potential to aid the movement of diamondback moth and aster leafhoppers northward on to the Canadian prairies from Mexico, southern and central USA as well as the Pacific Northwest.  Diamondback moth pheromone traps deployed across the prairies confirm their arrival – many thanks to the people who deploy and do the weekly monitoring!

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

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

Weekly Update – Cutworms

Jennifer Otani
Week 1

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 through May.  Be sure to read more about Pale western cutworms.

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 Manitoba Agriculture and Rural Initiatives 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”.  Once data entry occurs, growers can view the live 2017 cutworm map which is updated daily.

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

Weekly Update – Cereal leaf beetle

Jennifer Otani, Ross Weiss and Owen Olfert
Week 1

Cereal leaf beetle (Oulema melanopus) – As of May 1, 2017, the CLB model indicates that oviposition has begun in the Lethbridge and Swift Current areas.

Lifecycle and Damage:
Adult: Adult cereal leaf beetles (CLB) have shiny bluish-black wing-covers (Fig. 1). 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 1. 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. 2).  When the larva completes its growth, it drops to the ground and pupates in the soil. 

Figure 2.  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 – Predicted Grasshopper Development

Ross Weiss, Owen Olfert and prairiepest_admin
Week 1

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 1, 2017, model output predicted embryological mean development was 56%; the greatest development was predicted to be across the southern prairies. Embryological development was very similar to long term averages (57%) though marginally slower than 2016 (62%).

Reminder – The Prairie Pest Monitoring Network’s 2017 Grasshopper Forecast Map (Figure 1) was released in January.  While spring temperatures, soil moisture conditions, and precipitation can all have an impact on overwintered grasshopper eggs, growers in areas highlighted orange or red in the map below should be vigilant as nymphs begin to hatch this season.

Figure 1. Prairie Pest Monitoring Network’s 2017 Grasshopper Forecast Map.

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 – Monarch migration

Jennifer Otani
Week 1

We again track the migration of the Monarch butterflies and they move north by checking the 2017 Monarch Migration Map!  A screen shot of the map has been placed below as an example (retrieved 04May2017) but follow the hyperlink to check the interactive map!