Insect of the Week – Wheat midge

Jennifer Otani
Week 7

This week’s Insect of the Week is the wheat midge. Larvae feed on the surface of developing wheat kernels in spring and winter wheat, durum wheat, triticale and occasionally spring rye. Damage includes aborted, shrivelled, misshapen, cracked, or scared kernels. This lowers grain yield, quality and grade.

For more information on the wheat midge, visit our Insect of the Week page.

Wheat midge – larva (Mike Dolinski,

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

Weekly Update – Greetings!

Owen Olfert, Meghan Vankosky, Jennifer Otani, David Giffen, Kevin Floate and Erl Svendsen
Week 7


Access the complete Weekly Update either as a series of Posts for Week 7 (Jun 15, 2017) OR downloadable PDF version.

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.

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Weekly Update – Weather Synopsis

Ross Weiss, David Giffen, Owen Olfert and prairiepest_admin
Week 7

Weather synopsis – Over this past week, average temperatures were similar to last week and only marginally cooler than long term averages for early June. Average temperatures were warmest in southern Manitoba with cooler conditions occurring across Alberta. 

 This second map presents the 30 Day Average Temperature. Average temperatures were greatest in southern regions of Manitoba and central Alberta.

The map below indicates that 7 Day Accumulated Precipitation was greatest across Alberta while central and southern Saskatchewan continued to be dry. 

The map below indicates that the rainfall amounts for the past month (May 13 – June 11) were average to above-average in Alberta and below-average for Manitoba and Saskatchewan.

The updated growing degree day map (GDD) (Base 5ºC, March 1 – June 11, 2017) is below:

While the growing degree day map (GDD) (Base 10ºC, March 1 – June 11, 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.

Weekly Update – Predicted Grasshopper Development

Ross Weiss, Owen Olfert and prairiepest_admin
Week 7

Grasshopper Simulation Model Output – Simulation modelling is used to predict grasshopper development across the prairies. Weekly temperature data is incorporated into the model which calculates estimates of grasshopper development stages based on biological parameters for Melanoplus sanguinipes (Migratory grasshopper). Predicted hatch for June 11, 2017, was 52% (23% last week) with 32% of the population in the first instar, 15% second instar and 15% third instar. 

The greatest development was predicted to be across southern regions in all three provinces, particularly southeastern Alberta and a region extending south from Swift Current/Regina to the US border. 

Grasshopper populations near Saskatoon were predicted to be primarily in the second instar with appearance of some third and fourth instars. This week’s survey (southwest of Saskatoon) agreed with model predictions with first collections of a few fourth instars.  

Model output for Grande Prairie indicates that development continues to be approximately 10 days later than locations across the southern prairies.

Reminder:  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 – Predicted Bertha Armyworm Development

Ross Weiss, Owen Olfert and prairiepest_admin
Week 7

Bertha armyworm (Lepidoptera: Mamestra configurata– Emergence of adult moths is well underway. The map illustrates predicted appearance of adults (percent of the population) across the southern prairies; oviposition is predicted to begin this week with first hatch beginning later next week.

For those of you monitoring BAW pheromone traps, you may want to compare trap “catches” to the following reference photo kindly shared by Saskatchewan Agriculture:

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.

Weekly Update – Wheat midge

Ross Weiss, Owen Olfert and prairiepest_admin
Week 7

Wheat Midge (Sitodiplosis mosellana– The Insect of the Week features wheat midge!  

Simulation modelling is used to predict wheat midge emergence across the Canadian prairies.  The model predicted that wheat midge adults should emerge in July. The following graphs indicate that adult emergence at Saskatoon (Fig. 1) could be two weeks later than at Melfort (Fig. 2). Though average temperatures have been similar for both locations, model output indicates that dry conditions at Saskatoon (6 mm since June 1) may result in delayed emergence. Adequate moisture at Melfort (20 mm since June 1) has resulted in expected emergence patterns. Predicted rainfall for this week should result in emergence patterns that are more typical.

Figure 1. Predicted wheat midge development at Saskatoon SK.

Figure 2.  Predicted wheat midge development at Melfort SK.

As a refresher, the 2017 wheat midge forecast map circulated in January can be accessed at our Risk and Forecast Maps Post.  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 – Pea leaf weevil

Ross Weiss, Owen Olfert and prairiepest_admin
Week 7

Pea Leaf Weevil (Sitona lineatus– Oviposition is predicted to have peaked across central and southern regions of Alberta and Saskatchewan.  Hatch should be underway in pea fields near Lethbridge while hatching is predicted to occur this week near Saskatoon. 

Biological and monitoring information related to pea leaf weevil in field crops is posted by the province of Alberta and a NEWLY UPDATED PPMN monitoring protocol is available!

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

Ross Weiss, Owen Olfert and prairiepest_admin
Week 7

Alfalfa Weevil (Hypera postica) – Recent warm weather has resulted in rapid alfalfa weevil development. Model output indicates that 98% of the hatch is complete (less than 80% last week). Larval populations should be predominantly in the second (35%) and third (46%) instars.

Alfalfa growers are encouraged to check the Alfalfa Weevil Fact Sheet prepared by Dr. Julie Soroka (AAFC-Saskatoon) and 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).  That guide is available in both a free English-enhanced or French-enhanced version.

Weekly Update – White grubs in field crops

Kevin Floate and prairiepest_admin
Week 7

Scarabaeidae – Each June brings scattered reports across the Prairies of white grubs associated with crop damage.  In fact, several species of Aphodius, Phyllophaga, Polyphylla or even small Aetenius produce larvae described as “white grubs”.  

Recently, crop damage reports have been associated with a grub identified as the larvae of the beetle Aphodius distinctus (see below). This common beetle is not known to be a pest, but there is an ongoing effort to gather information to develop a ‘pest’ profile.  Additional information is online at Top Crop Manager. Please send reports of this insect and associated information to Dr. Kevin Floate (Agriculture and Agri-Food Canada, Lethbridge, AB).

2017 Wind Trajectories

Ross Weiss, Serge Trudel, Owen Olfert and prairiepest_admin
Week 7


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

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

Provincial Insect Pest Reports

John Gavloski, Scott Hartley and Scott Meers
Week 7

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 is prepared by John Gavloski and Pratisara Bajracharya the latest issue (Insect and Disease Update).

● Saskatchewan’s Crop Production News – 2017 – Issue #2 prepared by Scott Hartley and Danielle Stephens is now posted and includes the latest update on pea leaf weevil.

● Watch for Alberta Agriculture and Forestry’s Call of the Land and access the most recent Insect Update provided by Scott Meers.