Wind Trajectories

Agriculture and Agri-Food Canada (AAFC) and Environment and Climate Change Canada (ECCC) have been working together to study the potential of trajectories for monitoring insect movements since the late 1990s.

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

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

Weekly Update

Another BIG Weekly Update – several predictive model updates have been generated this week! Find updated information for bertha armyworm, grasshoppers, cereal leaf beetle, alfalfa weevil, wheat midge and pea leaf weevil.  Keep scrolling down and it’s time to get in fields to scout!

Access information to support your in-field insect monitoring efforts in the complete Weekly Update either as a series of Posts for Week 8 OR a downloadable PDF.

Questions or problems accessing the contents of this Weekly Update? Please email Meghan.Vankosky@canada.ca or Jennifer.Otani@canada.ca. Past “Weekly Updates” can be accessed on our Weekly Update Blog Page.

Corn Pests / Feature Entomologist: Maya Evenden

This week’s Insect of the Week feature crop is corn, which has become more prominent on the Prairies. Our feature entomologist this week is Maya Evenden (Department of Biological Sciences, University of Alberta).

Corn Crop
cc by 2.0 Edwin Ijsman

While the bulk of Canadian corn is grown in Ontario and Quebec, the Prairies are not without robust corn production, split between corn for grain and corn for silage. In 2019, corn was grown on 404,800 hectares (992,300 acres) across the Prairies, producing 5.44 million metric tonnes (6 million US tons). Over three quarters of this amount was corn for silage, and the remainder corn for grain.

Corn crops are susceptible to several pests. 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.

Corn pests:
  • Armyworm
  • Black cutworm
  • Brown marmorated stink bug
  • Cereal leaf beetle
  • Chinch bug
  • Corn earworm
  • Corn leaf aphid
  • Darkside cutworm
  • Dingy cutworm
  • European corn borer
  • Fall armyworm
  • Glassy cutworm
  • Grasshoppers
  • Green cloverworm
  • Green-tan grass bugs
  • Greenbugs
  • Pale western cutworm
  • Potato aphid
  • Redbacked cutworm
  • Rice leaf bug
  • Saltmarsh caterpillar
  • Twospotted spider mite
  • Variegated cutworm
  • Wheat stem sawfly
  • Wireworms
European corn borer, larval stage
AAFC

Entomologist of the Week: Maya Evenden

Name: Maya Evenden
Affiliation: Department of Biological Sciences, University of Alberta
Contact Information: mevenden@ualberta.ca; @MayaEvenden on twitter

How do you contribute in insect monitoring or surveillance on the Prairies?
  • My research group develops semiochemical-based monitoring tools that target insects of environmental and economic impact in Alberta.  For field crop pests, we have developed and tested semiochemical-based monitoring tools for 1) diamondback moth; 2) pea leaf weevil; 3) red clover casebearer 4) cutworms and 5) wheat midge.
  •  We also work on other non-target species that are captured in monitoring traps (bycatch).  This provides information on biodiversity and community composition of arthropods in managed agroecosystems.
  • I am an active member of the Prairie Pest Monitoring Network.
In your opinion, what is the most interesting field crop pest on the Prairies?
  • I am partial to the Bertha armyworm because:
    • It’s a moth (and I love moths)
    • Larvae march like an army
    • It is a native insect that exploits agricultural crops planted in its habitat
    • Pheromone-based monitoring is useful because moths can be caught before eggs are laid in the field to warn producers of the current season’s feeding damage
What is your favourite beneficial insect?
  • I like the diamondback moth parasitoid, Diadegma insulare because:
    • It is a specialist on diamondback moth (although it will parasitize other Lepidoptera)
    • It tracks diamondback moth migration to the Prairie Provinces
    • It can result in a high level of parasitism of diamondback moth populations
    • It is highly susceptible to pesticide applications
Tell us about an important project you are working on right now.
  • We are currently documenting the biodiversity and abundance of ground beetles in pulse crops in Alberta.  We will find out the community composition of ground beetle predators in pulse fields, the landscape features with which they are associated, and what they eat.  My PhD student Maggie MacDonald is leading this research and we are collaborating with Dr. Boyd Mori on the assessment of beetle gut content using molecular methods.
What tools, platforms, etc. do you use to communicate with your stakeholders?
  •  We communicate with stakeholders through in-person updates at field days and annual meetings.  In addition, we publish updates in grower magazines (i.e. Top Crop Manager), newsletters and grower websites.  We communicate with grower organizations through research updates.  I also communicate directly with stakeholders through email and twitter @MayaEvenden.

Weekly Update

Greetings!

Access the complete Weekly Update either as a series of Posts for Week 08 (May 30, 2019) OR a downloadable PDF. Check out the Insect of the Week.

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

Weather synopsis – This week (May 21-28, 2019) cool, dry conditions continued to occur across the prairies. Though temperatures are warming up, early growing season daily average temperatures continue to be cooler than normal. 

Throughout this past week, the average temperature was approximately 1 °C cooler than normal (Fig. 1).  Compared to last week, the prairie-wide average daily temperature was 3 °C warmer. The warmest temperatures were observed across the Parkland region of the prairies.

Figure 1. Average temperature (°C) across the Canadian prairies the past seven days (May 22-28, 2019).

The average 30-day temperatures were approximately 3 °C cooler than average (Fig. 2). 

Figure 2. Average temperature (°C) across the Canadian prairies the past 30 days (April 28-May 28, 2019).

Seven-day cumulative rainfall (Fig. 3) indicated that minimal rain was observed across large areas of SK. Most locations reported less than 5 mm.  Wetter conditions were reported in a corridor between Lethbridge and Calgary AB. Most of MB and southeast SK had rainfall amounts that were greater than 10 mm (Fig. 3). 

Figure 3. Cumulative precipitation observed the past seven days across the Canadian prairies (May 22-28, 2019).
Figure 4. Mean temperature differences from Normal across the Canadian prairies from April 30-May 27, 2019.
Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (30May2019). Access the full map at http://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=true

Across the prairies, rainfall amounts for the past 30 days (April 28-May 28, 2019) have been approximately 50% of normal (Fig. 6).  The 30-day rainfall totals have improved in MB and southwest SK.  

Figure 5. Cumulative precipitation observed the past 30 days across the Canadian prairies (April 28-May 28, 2019).

Growing season rainfall (April 1 – May 28) amounts have been well below average for most of the prairies, particularly in west central SK and eastern regions of AB (Fig. 6). 

Figure 6. Cumulative precipitation observed for the growing season across the Canadian prairies (April 1-May 28, 2019).

Almost all of the prairies has had growing season rainfall amounting to 85 %, or less, than average. 

Figure 6. Percent of Average precipitation across the Canadian prairies for the growing season (April 1-May 28, 2019).
Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (30May2019).  
Access the full map at http://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=true

Soil moisture values are low across most of the prairies. 

Figure 7. Modeled soil moisture (%) across the Canadian prairies (up to May 28, 2019).

The two week forecast is not predicting significant rainfall for the prairies. The Agroclimate National Risk Report for May 7 to May 22, 2019 reports that there is less than a 30% chance of rainfall amounting to >25 mm (May 29-June 4, 2019). The report states that “No rain is expected in the week ahead in areas currently experiencing drought conditions such as southwestern Saskatchewan”.

Figure 8. Forecast probability of total precipitation >25 mm for the period of May 29 to June 4, 2019.
Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and  was retrieved (30May2019).  
Access the full map at http://www.agr.gc.ca/eng/programs-and-services/drought-watch/agroclimate-national-risk-report-may-7-to-may-22-2019/?id=1556301780170

The growing degree day map (GDD) (Base 5 ºC, April 1-May 27, 2019) is below (Fig. 9):

Figure 9. Growing degree day (Base 5 ºC) across the Canadian prairies for the growing season (April 1-May 27, 2019).
Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (30May2019).  
Access the full map at http://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=true

The growing degree day map (GDD) (Base 10 ºC, April 1-May 15, 2019) is below (Fig. 10):

Figure 10. Growing degree day (Base 10 ºC) across the Canadian prairies for the growing season (April 1-May 27, 2019).
Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (30May2019).  
Access the full map at http://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=true

The lowest temperatures (°C) observed the past seven days range from -6 to 6 °C in the map below (Fig. 11).

Figure 11. Lowest temperatures (°C) observed across the Canadian prairies the past seven days (May 23-29, 2019).
Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (30May2019).  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 range from 14 to at least 32 °C in the map below (Fig. 12).

Figure 12. Highest temperatures (°C) observed across the Canadian prairies the past seven days (May 23-29, 2019).
Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (30May2019).  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.

Active Wildfires – Natural Resources Canada

Active Wildfires – Natural Resources Canada posts live interactive maps like the one below (Fig. 1). Access their webpage for more information and to stay current on the various active wildfires burning across Canada.

Figure 1.  Natural Resources Canada’s Canadian Wildland Fire InformationSystem’s Interactive Map (retrieved on 28May2019 from http://cwfis.cfs.nrcan.gc.ca/interactive-map )

Access the following wildfire maps:

Wind Trajectories

Agriculture and Agri-Food Canada (AAFC) and Environment and Climate Change Canada (ECCC) have been working together to study the potential of trajectories for monitoring insect movements since the late 1990s.

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

Prairie Crop Disease Monitoring Network

The Prairie Crop Disease Monitoring Network (PCDMN) represents the combined effort of our prairie pathologists who work together to support in-field disease management in field crops.  

In 2019, the PCDMN will release a series of weekly Cereal Rust Risk Reports throughout May and June.  Information related to trajectory events based on forecast and diagnostic wind fields and cereal rust risk is experimental, and is OFFERED TO THE PUBLIC FOR INFORMATIONAL PURPOSES ONLY. 

Background:  Agriculture and AgriFood Canada (AAFC) and Environment and Climate Change Canada (ECCC) have been working together to study the potential of trajectories for monitoring insect movements since the late 1990s. Trajectory models are used to deliver an early-warning system for the origin and destination of migratory invasive species, such as diamondback moth. In addition, plant pathologists have shown that trajectories can assist with the prediction of plant disease infestations and are also beginning to utilize these same data. An introduction will be presented of efforts to identify wind trajectory events that may bring rust urediniospores into Western Canada from epidemic areas in the central and Pacific northwest (PNW) regions of the USA. Identification of potential events as well as an assessment of epidemic severity from source locations, and prairie weather conditions, will be used to assess the need for prompt targeted crop scouting for at-risk regions of the Canadian Prairies.

This week, two documents are available from the PCDMN:

Synopsis of May 21-27, 2019, Weekly Cereal Rust Risk Report: 

1. Pacific Northwest – Given limited stripe rust development in the PNW, a low number of recent wind trajectories from the PNW, cool and relatively dry Prairie weather conditions, and generally early stages of Prairie crop development, as of May 27, 2019, the risk of stripe rust appearance from the PNW is limited and scouting for this disease is not urgent.

2. Texas-Oklahoma corridor – Although leaf and stripe rust development continues in this corridor, especially Oklahoma, the disease is mainly affecting the lower canopy at generally low levels.  In addition, crops are advancing towards maturity and thus will become less of a source of rust inoculum.  There have been a low number of recent wind trajectories from this area, cool and relatively dry Prairie weather conditions, and generally early stages of Prairie crop development.  Thus, as of May 27, 2019 the risk of leaf and stripe rust appearance from the Texas-Oklahoma corridor is low and scouting for these diseases is not urgent.

3. Kansas-Nebraska corridor – Although leaf and stripe rust development continues in Kansas, it is at low-moderate levels and mainly in the middle portions of crop canopies.  There have been a low-moderate number of recent wind trajectories from this area, cool and relatively dry Prairie weather conditions, and generally early stages of Prairie crop development.  Thus, as of May 27, 2019 the risk of leaf and stripe rust appearance from the Kansas-Nebraska corridor is low and scouting for these diseases is not urgent, but further development of rust in these regions may increase the risk. 

4. Where farmers or consultants noticed stripe rust development on winter wheat in the fall of 2018, it is recommended to scout winter wheat fields that have resumed growth this spring.  Scouting is especially critical where the variety being grown is susceptible to stripe rust.  Currently, there are no early spring reports of stripe rust on winter wheat.

5.  Access the full downloadable report.

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).  

As of May 28, 2019, predicted grasshopper egg development was 72% (66% last week) and is similar to long term average values (75%) (Fig. 1).  Across the prairies, the grasshopper hatch is just beginning with most locations having less than 5% hatch. 

Figure 1. Predicted grasshopper (Melanoplus sanguinipes) embryological development across the Canadian prairies as of May 28, 2019. 
Figure 2. Predicted percent of grasshopper (Melanoplus sanguinipes) population at first instar stage across the Canadian prairies (as of May 28, 2019). 

Model runs for Grande Prairie (Fig. 3), Lethbridge (Fig. 4) and Saskatoon (Fig. 5) were projected to June 15, 2019. Results for Lethbridge and Saskatoon indicated that second instars will begin to appear next week. Hatch in near Grande Prairie is  predicted to be approximately one week later.  Development is predicted to be more advanced in northern areas of the Peace River region. 

Figure 3. Predicted status of Melanoplus sanguinipes populations near Grande Prairie AB as of  May 28, 2019.  
Figure 4. Predicted status of Melanoplus sanguinipes populations near Lethbridge AB as of  May 28, 2019.  
Figure 5. Predicted status of Melanoplus sanguinipes populations near Saskatoon SK as of  May 28, 2019.  

This week we surveyed roadsides south of Saskatoon. Though counts were low, melanoplines were primarily first with a few second instars. Slant faced grasshoppers were most abundant, particularly Aeropedellus clavatus.

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 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.

Pea leaf weevil

Pea Leaf Weevil (Sitona lineatus– Model runs for Red Deer AB (Fig. 1) and Swift Current SK (Fig. 2) were projected to June 15, 2019. Results indicated that oviposition should begin early next week. Model predictions, based on long term normal weather data predict that initial hatch near Saskatoon should occur on May 29th.

Figure 1. Projected predicted status of pea leaf weevil populations near Red Deer AB to
June 15, 2019 using long term average temperatures.
Figure 2. Projected predicted status of pea leaf weevil populations near Swift Current SK to
June 15, 2019 using long term average temperatures.

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. 3, 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 and in the PPMN monitoring protocol.

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.

Cereal leaf beetle

Cereal leaf beetle (Oulema melanopus) – The CLB model was run for Brandon MB (Fig. 1), Lethbridge AB (Fig. 2), Grande Prairie AB (Fig. 3) and projected to June 15, 2019.  The cereal leaf beetle model indicates that eggs may begin to hatch later next week in Brandon (Fig. 1) and Lethbridge (Fig. 3). Hatch is predicted to be 4-7 days later in the Peace River region (Fig. 3).

Figure 1. Projected predicted status of cereal leaf beetle populations near Lethbridge AB to June 15, 2019,generated using long term average temperatures.
Figure 2. Projected predicted status of cereal leaf beetle populations near Brandon MB to June 15, 2019,generated using long term average temperatures.
Figure 3. Projected predicted status of cereal leaf beetle populations near Grande Prairie AB to June 15, 2019, generated using long term average temperatures.
 

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 measure 4.4-5.5 mm long (Photo: M. Dolinski).

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 (Photo: M. Dolinski).

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”.

Alfalfa weevil

Alfalfa Weevil (Hypera postica) – Degree-day maps of base 9°C are produced using the Harcourt/North Dakota models (Soroka et al. 2015).  Models predicting the development of Alfalfa weevil (AAW) across the prairies are updated weekly to help growers time their in-field scouting for second-instar larvae. 

Model runs for Brooks AB and Swift Current SK were projected to June 15, 2019.  The model runs indicate that second instar AAW should begin to appear over the next few days.  Third instar larvae are predicted to occur one week later. The warm weather over the next few days may speed up development.

Figure 1. Projected predicted status of alfalfa weevil populations near Brooks AB to June 15, 2019,using long term average temperatures.
Figure 2. Projected predicted status of alfalfa weevil populations near Swift Current SK to June 15, 2019,using long term average temperatures.

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).  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.

Predicted bertha armyworm development

Bertha armyworm (Lepidoptera: Mamestra configurata– Pupal development is approximately 40%. Average development is 48% (Fig. 1). 

Figure 1. Predicted bertha armyworm (Mamestra configurata) pupal development acrossthe Canadian prairies as of May 28, 2019. 

In order to determine when adults may emerge, the BAW model was run for Brandon MB (Fig. 2), Saskatoon SK (Fig. 3), Lethbridge AB (Fig. 4) and Edmonton AB (Fig. 5) and projected to June 30, 2019. Model projections indicate that adults will begin to emerge in mid June. Recent heat will advance development of pupae. Traps should be placed in fields when pupal development reaches 80%. Based on model projections, it is advisable that traps be placed in fields on or before June 7. 

Figure 2. Predicted development of bertha armyworm populations near Brandon MB projected to June 30, 2019.  
Figure 3. Predicted development of bertha armyworm populations near Saskatoon SK projected to June 30, 2019.   
Figure 4. Predicted development of bertha armyworm populations near Lethbridge AB projected to June 30, 2019.  
Figure 5. Predicted development of bertha armyworm populations near Edmonton AB projected to June 30, 2019.   

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” as an English-enhanced or French-enhanced version.

Painted Lady Butterfly

This week, Alberta Agriculture & Forestry’s Scott Meers noted painted lady butterfly larvae (Vanessa cardui).  The larvae are important to scout for because this species feeds on a wide range of host plants including soybean (Action threshold=>25% defoliation), sunflowers, borage and dry beans in addition to several species of thistles (including Canada thistle) and mallow. 

The “Field Crop and Forage Pests and their Natural Enemies in Western Canada: Identification and management field guide” includes photos of both the larvae and adult.  The guide is available as an English-enhanced or French-enhanced version.  The Butterflies and Moths of North America website tracks confirmed sightings of V. cardui (screenshot provided below; retrieved 30May2019).

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 2019 are posted here and includes an update posted May 29, 2019.

Saskatchewan‘s Crops Blog Posts includes a segment on “Early season scouting of cutworms” by Sara Doerksen posted in April 2019 and “Economic thresholds” by Kaeley Kindrachuk posted in May 2019.

•  Alberta Agriculture and Forestry’s Call of the Land regularly includes insect pest updates from Mr. Scott Meers. The most recent Call of the Land was posted March 18-22, 2019 but did not include an insect update.

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

Crop protection guides – Week 6

Cutworms – Week 5

Field heroes – Week 6

Flea beetles – Week 5

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

Ticks and Lyme disease – Week 4

Weather Radar – Week 6

Wind trajectories – Weeks 1-4

Insect of the Week – Japanese beetle (Popillia japonica)

Japanese beetle (Popillia japonica) adults
CC-BY 2.0 – C. Watts

The Japanese beetle (Popillia japonica) is an invasive pest that has been making steady inroads from the east since being first discovered in North America in 1916 (New Jersey) and in Canada in 1939 (Nova Scotia, Quebec). It has not reached the Prairies yet, but it is found in southern Ontario, Quebec, New Brunswick, Prince Edward Island and Nova Scotia. It has been detected in Vancouver,British Columbia and CFIA is leading a coordinated eradication program and has implemented efforts to prevent the pest’s spread outside Vancouver. The rest of British Columbia is still considered free of Japanese Beetle. In the USA, Minnesota and to the south and east is infested and North Dakota and south is partially infested. Montana and several other western USA states have implemented quarantine and phytosanitary regulations to protect their agriculture sector.

From late June to August, the adult Japanese beetle can attack the leaves and fruit of more than 300 species including ornamentals (birch, elm, maple, mountain ash, rose, zinnia), fruit and vegetables (apple, apricot, asparagus, blueberry, cherry, grape vine, plum, raspberry) and field crops (corn, soybean). The soil-dwelling larvae feed on roots of many species but prefer grass roots, damaging lawns, turf farms, golf courses and pastures.

The adult beetle is oval: 10-12 millimeters (0.5 inches) long by half as wide. It is metallic green with a brown head and metallic bronze wing coverings (elytra). Twelve white hair tufts are arranged along the outside edge of the back-half of the abdomen. Larvae are less than 25 millimetres (1 inch) at maturity and are a typical C-shaped white grub with a yellowish-brown head.

For more information see Canadian Food InspectionAgency (CFIA), United States Department of Agriculture (USDA) and Ontario Ministry of Agriculture, Food and Rural Affairs (OMAFRA) websites.

For information about previous featured insects, please visit our Insect of the Week page. For even more information on crop pests and their natural enemies, be sure to check out our newly updated Field Guide and Cutworm Guide, available for free download on our Insect Field Guide and Cutworm Field Guide pages.

Japanese beetle (Popillia japonica) larva
CC-BY-NC 3.0 – Jim Baker, North Carolina University
Japanese beetle (Popillia japonica) larval damage in turf
CC-BY-NC 3.0 – MG Kelin, USDA-ARS

Insect of the Week – Bruner grasshopper (Orthoptera: Acrididae)

The insect of the week is the Bruner grasshopper (Melanoplus bruneri).  Observed since the 1920s in Canada, this species is a relatively recent addition to the list of grasshopper pest species occurring in crop production areas. Previously, it was not considered a crop pest.

It is a medium-sized grasshopper (males 18-22 mm; females 22-27 mm) with dark and often reddish colour tones. It is similar in appearance and size to the migratory grasshopper (Melanoplus sanguinipes) but is distinguished by differences in the male genitalia. The Bruner grasshopper has recently become the predominant grasshopper species in many northern crop production areas of Alberta and parts of Saskatchewan. It occupies a wide geographic range and is found throughout much of Canada and the United States.

The Bruner grasshopper feeds mainly on broadleaf host plants but the species can feed upon several species of grasses. It has been observed in high numbers feeding in pulse crops, canola, and cereals.

Researchers are investigating if this species follows a two-year life cycle (i.e. do eggs require exposure to two winters before hatching?) in the Peace River region and parts of central Alberta.

For more information, see our Insect of the Week page!

Bruner grasshopper (Melanoplus bruneri) adult.
Photo credit: S. Barkley, Alberta Agriculture and Forestry.

Access these websites for more information related to the Bruner Grasshopper:

Access more information related to grasshoppers here.

Weekly Update

Greetings!

Field crop entomologists across the prairies are on the move with surveying and at field events.  Access the complete Weekly Update either as a series of Posts for Week 08 (June 28, 2018) OR a downloadable PDF version.  Also review the “Insect of the Week” for Week 8!

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 staff have been busy at field events and surveying so we direct you to the AAFC Drought Watch maps.  

Accumulated precipitation for the past seven days (June 27, 2018) is available from Agriculture and Agri-Food Canada (Fig. 1).

Figure 1.  Precipitation across the Canadian prairies the past seven days (June 27, 2018).Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (28Jun2018).  Access the full map at http://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=true&reset=1529635048320).

Accumulated precipitation for the growing season (April 01-June 27, 2018) is available from Agriculture and Agri-Food Canada (Fig. 2).

Figure 2.  Precipitation across the Canadian prairies for the current growing season (April 1-June 27, 2018).Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (28Jun2018).  Access the full map at http://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=true&reset=1529635048320).

The map below reflects the Highest Temperatures occurring over the past 7 days (June 27, 2018) across the prairies and is available from Agriculture and Agri-Food Canada (Fig. 3). 

Figure 3.  Highest temperature across the Canadian prairies the past seven days (June 21-27, 2018).
Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (28Jun2018).  Access the full map at http://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=true&reset=1529635048320).

The map below reflects the Lowest Temperatures occurring over the past 7 days (June 21-27, 2018) across the prairies and is available from Agriculture and Agri-Food Canada (Fig. 4).

Figure 4.  Lowest temperature across the Canadian prairies the past seven days (June 21-27, 2018).Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (28Jun2018).  Access the full map at http://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=true&reset=1529635048320).

The growing degree day map (GDD) (Base 10ºC, March 1 – June 24, 2018) is below:

The growing degree day map (GDD) (Base 5ºC, March 1 – June 24, 2018) 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.

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).  

As of June 24, 2018, the warm weather has resulted in rapid grasshopper development for populations near Saskatoon SK. Model output for Saskatoon predicts that hatch is complete and that populations are primarily in the 4th instar stage (Fig. 1). By comparison, last week’s model output indicated that populations should be primarily in the 2nd and 3rd instar stages. 

Figure 1.  Predicted grasshopper phenology at Saskatoon SK.
Values are based on model simulations for April 1 – June 24, 2018.

Grasshopper Scouting Steps: 

● Measure off a distance of 50 m on the level road surface and mark both starting and finishing points using markers or specific posts on the field margin.

● Starting at one end in either the field or the roadside and walk toward the other end of the 50 m making some disturbance with your feet to encourage any grasshoppers to jump. 

● Grasshoppers that jump/fly through the field of view within a one meter width in front of the observer are counted. 

● A meter stick can be carried as a visual tool to give perspective for a one meter width.  However, after a few stops one can often visualize the necessary width and a meter stick may not be required. Also, a hand-held counter can be useful in counting while the observer counts off the required distance. 

● At the end point the total number of grasshoppers is divided by 50 to give an average per meter. For 100 m, repeat this procedure. 

● Compare counts to the following damage levels associated with pest species of grasshoppers:

0-2  per m² – None to very light damage

2-4  per m² – Very light damage

4-8  per m² – Light damage

8-12 per m² – Action threshold in cereals and canola

12-24 per m² – Severe damage 

>24 per m² – Very severe damage

* For lentils at flowering and pod stages, >2 per m² will cause yield loss.

* For flax at boll stages, >2 per m² will cause yield loss.

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 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.

Predicted bertha armyworm development

Bertha armyworm (Lepidoptera: Mamestra configurata– As of June 24, 2018, BAW development continues to be 7-10 days ahead of normal development (Figs. 3 A and B). Pupal development is complete across the prairies (Fig. 1).

Near Saskatoon SK, BAW egg hatch is nearly complete and larvae are present (Fig. 2). Based on Long Term Climate Normal (LTCN) data, larvae generally begin to occur the last few days of June (Fig. 3).

Figure 2. Predicted BAW phenology at Saskatoon SK.
Values are based on model simulations for April 1 – June 24, 2018 and B) Long term climate normals.
Figure 3.  Predicted BAW phenology at Saskatoon SK.
Values are based on model simulations for Long Term Climate Normals (LTCN).

Many thanks to those who are checking a bertha armyworm pheromone trap on a weekly basis.  Please use the reference photo below kindly shared by Saskatchewan Agriculture to aid your identification and reporting of trap interceptions.  Note the kidney-bean white-patterned shape on each forewing but also know other cutworm species can resemble bertha armyworm moths.  Check carefully and thanks for your help!

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.

Keep track of the Provincial Entomologist Updates for the latest in-season pheromone trap monitoring results for 2018.  

Albertans can access the online reporting map (screenshot retrieved 28Jun2018 provided below for reference:

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.

Wheat midge

Wheat Midge (Sitodiplosis mosellana– As of June 24, 2018, the recent dry conditions near Saskatoon SK have resulted in delayed emergence of  adult wheat midge (Figs. 1 and 2).  Predictions for 2018 are similar to average values (Figs. 2 and 3). 

Figure 1.  Predicted wheat midge emerged based on degree-days accumulated across the Canadian prairies (as of June 24, 2018).
Figure 2.  Predicted wheat midge phenology at Saskatoon SK.
Values are based on model simulations for April 1 – June 24, 2018.
Model projections to July 15 are based on long term climate normal values for temperature and precipitation.
Figure 3.  Predicted wheat midge phenology at Saskatoon SK.
Values are based on model simulations for Long Term Climate Normals (LTCN).
Model projections to July 15 are based on long term climate normal values for temperature and precipitation.

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. 

Click here to review the 2018 wheat midge forecast map.  

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.  Additionally, more information 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.

Lygus in canola

Lygus bugs (Lygus spp.) – As of June 24, 2018, the Lygus model suggests that Saskatoon populations should consist of mostly 4th instar nymphs (Fig. 1). Predicted development for the 2018 growing season is greater than for development that is based on long term climate normals (Fig. 2).

Figure 1.  Predicted Lygus phenology at Saskatoon SK.
Values are based on model simulations for April 1 – June 24, 2018.
Figure 2.  Predicted Lygus phenology at Saskatoon SK.
Values are based on model simulations for Long Term Climate Normals.

Remember – 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.

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 and check the online map for CSPW posted by Alberta Agriculture and Forestry (screenshot is provided below for reference; retrieved 28Jun2018).

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

Request for Cereal Leaf Beetle Larvae

Reminder – Researchers need your help – They are looking for LIVE cereal leaf beetle larvae from any field across the Canadian prairies in order to assess Tetrastichus julis parasitism rates.

If larvae are encountered in 2018, please carefully collect 20-30 of them and put them with some cereal leaves and a moist paper towel in a hard container (e.g. plastic yogurt container) with holes poked in the lid for air. Pack the parcel with ice packs, label with your name, date, crop type, and location, and send them to us.  Email or phone us for information on how to ship for free.

What’s in it for you? Learn if cereal leaf beetle is being controlled by natural enemies in your field. If you need T. julis, we may be able provide you with some.

Contact:
Dr. Haley Catton, Agriculture and Agri-Food Canada
5403 – 1 Ave S, Lethbridge, Alberta T1J 4B1
403-317-3404, haley.catton@canada.ca

Pea leaf weevil

Pea Leaf Weevil (Sitona lineatus– As of June 24, 2018, the PLW model predicted that hatch is nearly complete and the population is primarily in the larval stage in the Saskatoon area (Fig. 1).  Development in 2018 is faster than long term average (Fig. 2).  

Figure 1.  Predicted pea leaf weevil phenology at Saskatoon SK.
Values are based on model simulations for April 1 – June 24, 2018.
Figure 2.  Predicted pea leaf weevil phenology at Saskatoon SK.
Values are based on model simulations for Long Term Climate Normals (LTCN).

Pea leaf weevil larvae develop under the soil over a period of 30 to 60 days. They are “C” shaped with a dark brown head capsule. The rest of the body is a milky-white color (Fig. 3 A). Larvae develop through five instar stages. In the 5th instar, larvae range in length from 3.5 – 5.5 mm. First instar larvae bury into the soil after hatching, and search out root nodules on field pea and faba bean plants. Larvae enter and consume the microbial contents of the root nodules (Fig. 3 B). These root nodules are responsible for nitrogen-fixation, thus pea leaf weevil larval feeding can affect plant yield and the plant’s ability to input nitrogen into the soil. 

Figure 3.  Pea leaf weevil larva in soil (A) and field pea root nodules damaged by larval feeding (B).  Photos: L. Dosdall).

Biological and monitoring information related to pea leaf weevil in field crops is posted by the province of Alberta and in the PPMN monitoring protocol.

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.

White grubs in field crops

Scarabaeidae – Reminder – 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).

Field Heroes

As crops continue to grow, please consider the vital role beneficial organisms have in your fields.  Please make use of the Scouting Guides freely available on the Field Heroes website.  Each guide includes valuable information and photos to help identify the contents of a sweep-net and to increase understanding of the impact of beneficial insects. Please share and encourage use of the Scouting Guides.

Be sure to follow @FieldHeroes on Twitter for practical tips and information. Please tag @FieldHeroes in your own Tweets about beneficials. Re-Tweets are great, too.

Thanks to Western Grains Research Foundation for their support of this important campaign. This initiative is not possible without the support and advice of enthusiastic members of the Prairie Pest Monitoring Network. Our research is having a tangible impact on growers’ pest management decisions.

Link here to access a complete list of all the PPMN Blog Posts related to Natural Enemies!

Monarch migration

We continue to track the migration of the Monarch butterflies as they move north by checking the 2018 Monarch Migration Map!  A screen shot of the map has been placed below as an example (retrieved 28Jun2018) but follow the hyperlink to check the interactive map.  They are in Manitoba and moving west through southern Saskatchewan this week!

Visit the Journey North website to learn more about migration events in North America and visit their monarch butterfly website for more information related to this fascinating insect.  

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.  Areas highlighted yellow then orange are approaching sufficient heat accumulation for mosquitoes to emerge while mosquitoes will be flying in areas in red so wear DEET to stay protected!

Health Canada posts information related to West Nile Virus in Canada.  Health Canada also tracks WNV through human, mosquito, bird and horse surveillance.  The 2017 WNV surveillance map for human cases is available here but a screenshot is posted below for reference.

Figure 1.  As of surveillance week 49, ending December 9, 2017, the preliminary data indicated 197 human cases of WNV in Canada; twenty-five from Québec, 159 from Ontario, five from Manitoba, seven from Alberta, and one from British Columbia.

The Canadian Wildlife Health Cooperative compiles and posts information related to their disease surveillance for West Nile Virus in birds.  As of June 28, 2018, 642 birds were examined and zero have tested positive for West Nile virus

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 Update for 2018 is accessed here. Review the most recent update (June 6, 2018) prepared by John Gavloski and Holly Derksen. The insect update notes flea beetles in canola and cutworms with monitoring for alfalfa weevil larvae underway. Diamondback moth trap numbers remain low and bertha armyworm pheromone traps will go up this week.

Saskatchewan‘s Crop Production News for 2018 is posted with Report #3 now available. Insect monitoring information is included in the article, “Canola plants disappearing? Scout the field to look for cutworm damage”. Saskatchewan growers can review articles to assess plant stand densities in flax or canola, and for flea beetles, pea leaf weevils. Also note the following diamondback moth pheromone trap interception counts from across the regions (updated June 15, 2018):

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 on June 21, 2018) noting that bertha armyworm moths were detected this first week of pheromone monitoring (check online map), onset of flowering in canola signalling the need for in-field monitoring for cabbage seedpod weevil, continued grasshopper calls from the south and advice to scout now while nymphs are easier to manage, Nutall’s blister beetle transiently showing up in some fields (blister beetle post), and the presence of the beneficial stiletto fly larvae which is a predator within the soil profile and targets wireworm larvae.

Previous Posts

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

Alfalfa weevil – Week 6

Cereal aphid manager (CAM) – Week 2
Cereal leaf beetle – Week 5
Crop protection guides – Week 2
Cutworms – Week 4

Diamondback moth – Week 7

Flea beetles – Week 4

PMRA Pesticide Label Mobile App – Week 4

Scouting charts (canola and flax) – Week 3

Ticks and Lyme Disease – Week 4

Weather radar – Week 3
Wind trajectories – Week 6
Wireworm distribution maps – Week 6

Crop reports

Crop reports are produced by:

The following crop reports are also available:

Insect of the Week – Macroglenes penetrans

This week’s Insect of the Week is a beneficial wasp from the Family Pteromalidae named Macroglenes penetrans. It is an important natural enemy of wheat midge.  The wasp is a parasitoid that lives within the wheat midge larva and overwinters within the host.  In the spring, the parasitoid larva develops to emerge from the wheat midge cocoon buried in the soil and seeks out wheat midge eggs.


For more information about M. penetrans, see our Insect of the Week page.



Macroglenes penetrans – adult (AAFC)

Follow @FieldHeroes to learn more about Natural Enemies that are working for you for FREE to protect your crops!


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

Weekly Update – Greetings!

Greetings!

Access the complete Weekly Update either as a series of Posts for Week 8 (Jun 22, 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.

Subscribe to the Blog by following these easy steps!

Weekly Update – Weather Synopsis

Weather synopsis – This past week our average temperatures were cooler than last week, and 2 – 3°C cooler than long term averages for mid-June (Fig. 1).  The second map presents the 30-day average temperature (Fig. 2).  

Figure 1. Average temperature across the Canadian prairies from June 4-11, 2017.


Figure 2. Average temperature across the Canadian prairies from May 19-June 19, 2017.

Temperature – The seven-day accumulated precipitation was greater than 15 mm with southeast Saskatchewan and southwest Manitoba reporting amounts in excess of 40 mm (Fig. 3).  

Figure 3. Accumulated precipitation across the Canadian prairies from June 11-18, 2017.



Compared to last week, the 30-day rainfall amounts are similar to long term average values for southern Manitoba, southeast Saskatchewan and southwest Alberta (Fig. 4). A large region in south and central Saskatchewan is reporting well below normal precipitation.

Figure 4. Percent of average precipitation from May 20-June 18, 2017.



The following is the accumulated precipitation for the growing season up to June 18, 2017.





The updated growing degree day map (GDD) (Base 5ºC, March 1 – June 18, 2017) is below:



While the growing degree day map (GDD) (Base 10ºC, March 1 – June 18, 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 – Alfalfa weevil

Alfalfa Weevil (Hypera postica) – The model output for alfalfa weevil is not signficantly different that that posted last week for June 22nd (Week 7).

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 – Predicted Grasshopper Development

Grasshopper Simulation Model Output – Predicted hatch was 71% (52% last week) with 30% of the population in the first instar, 26% second instar, 12% third instar and 2% in the fourth instar. Across the prairies, the mean developmental stage was second instar. The greatest development was predicted to be across southern regions in all three provinces. 





Grasshopper populations near Saskatoon were predicted to be primarily in the second instar this week with the appearance of third and fourth instars. Model output suggests that grasshopper development is slightly ahead of average development. Based on long term meteorological data, populations should be predominantly in the first and second instars with a low number being third instars. This week’s survey (SW of Saskatoon) indicates that most melanopline grasshoppers are already in the second and third numbers.  





Grasshopper Scouting Steps: 

● Measure off a distance of 50 m on the level road surface and mark both starting and finishing points using markers or specific posts on the field margin.

● Starting at one end in either the field or the roadside and walk toward the other end of the 50 m making some disturbance with your feet to encourage any grasshoppers to jump. 

● Grasshoppers that jump/fly through the field of view within a one meter width in front of the observer are counted. 

● A meter stick can be carried as a visual tool to give perspective for a one meter width.  However, after a few stops one can often visualize the necessary width and a meter stick may not be required. Also, a hand-held counter can be useful in counting while the observer counts off the required distance. 

● At the end point the total number of grasshoppers is divided by 50 to give an average per meter. For 100 m, repeat this procedure. 
● Compare counts to the following damage levels associated with pest species of grasshopers:

0-2  per m² – None to very light damage
2-4  per m² – Very light damage
4-8  per m² – Light damage
8-12 per m² – Action threshold in cereals and canola


12-24 per m² – Severe damage 
>24 per m² – Very severe damage



* For lentils at flowering and pod stages, >2 per m² will cause yield loss.
* For flax at boll stages, >2 per m² will cause yield loss.

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

Bertha armyworm (Lepidoptera: Mamestra configurata– Bertha armyworm should be in the adult stage across the prairies this week.  The map illustrates predicted appearance of adults (percent of the population) across the southern prairies.

For those monitoring BAW pheromone traps, 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

Wheat Midge (Sitodiplosis mosellana– Reminder – The previous Insect of the Week (Week 7) features wheat midge!  


Simulation modelling is used to predict wheat midge emergence across the Canadian prairies.  The model has not changed significantly from last week. The map below predicts the geographic distribution and corresponding accumulation of heat units necessary for wheat midge to emerge from puparia developing in the soil.  





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. 




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.  



NEW – Alberta Agriculture and Forestry has also released a YouTube video describing in-field monitoring for wheat midge this week.  


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.

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.


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 posted a live CSPW map and online reporting tool for growers.  A screenshot (retrieved 22Jun2017) is included below.


Weekly Update – Nysius niger

Nysius niger (Lygaeidae) – Agrologists in Saskatchewan have been querying a greyish-black bug spotted this week in some fields of canola, soybeans and flax.  Photos and descriptions suggest Nysius niger, an ~4mm long lygaeid, is being observed (Fig. 1 and 2). Reports of damage in canola have been matched with observations of these insects active on plants growing in good conditions with no apparent damage. Reports of damage in canola and flax indicate the bugs are feeding on the main stem near the soil surface.


Growers should be cautious – there is no data confirming whether or not Nysius niger is a pest causing consistent levels of economic damage.  Insects can feed on field crop species yet never inflict measurable levels of damage and are therefore not worth managing.  Careful scouting is warranted to assess how these insects are feeding AND if damage is occurring and to what extent.  Also remember our @FieldHeroes who benefit from less insecticide use and instead reserve insecticide use for economically important pests that cause well-researched levels of damage.


Figure 1. Nysius niger adult on the soil surface in a 
canola field in Saskatchewan photographed by J. Bogden.



Figure 2.  Lygaeid nymphs observed in the above 
canola field photographed by J. Bogden.


Weekly Update – White grubs in field crops

Scarabaeidae – Reminder – 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).

Weekly Update – Field Heroes

@Field Heroes – Western Grains Research Foundation is supporting a new initiative to help growers, agrologists and the general public learn more about beneficial arthropods active in field crops.  Provincial entomologists from Manitoba, Alberta, and Saskatchewan, along with input from AAFC researchers, are working with Synthesis, a communications company, to promote and increase awareness of these incredible arthropod heroes!

Follow @FieldHeroes for great information on these beneficials.  


NEW – Access great information on beneficials to support in-field monitoring at http://www.fieldheroes.ca/


The website includes scouting guides to help identify and link pest/beneficial combinations – all aimed at helping growers and agrologists understand and preserve the many arthropods hard at work in fields across the Canadian prairies.

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 for 2017 is prepared by John Gavloski and Pratisara Bajracharya and read Issue #5 (June 21, 2017) noting alfalfa weevil and lingering cutworm issues in that province.

● Saskatchewan’s Crop Production News – 2017 – Issue #2 prepared by Scott Hartley and Danielle Stephens is now posted. It includes updates on how to scout for pea leaf weevil and aster yellows that can occur in all crops. Additionally, very low DBM numbers have been intercepted in pheromone traps deployed throughout Saskatchewan (e.g., seasonal cumulative totals of 10-14 moths per trap were reported “peaks”.


● Watch for Alberta Agriculture and Forestry’s Call of the Land and access the most recent Insect Update (June 22, 2017) provided by Scott Meers. That report notes cabbage seedpod weevil scouting has begun in southern Alberta, isolated reports of red turnip beetle in a few fields in east-central Alberta, the appearance of early instar grasshoppers (1-3 instar stages) west of Edmonton and in the Peace River region despite the weather, and low pea aphid numbers so far in southern Alberta.

Crop reports

Crop reports are produced by:
• Manitoba Agriculture, Rural Development (June 19, 2017)
• Saskatchewan Agriculture Crop Report (June 13-19, 2017)
• Alberta Agriculture and Forestry Crop Report (June 13, 2017)


Weekly Update – Monarch migration

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 22Jun2017) but follow the hyperlink to check the interactive map!  They’ve migrated into southern Manitoba and into southeast Saskatchewan! 

Weekly Update – Previous Posts

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

Brood X Cicadas


Canola scouting chart

Cereal leaf beetle
Crickets with your popcorn
Crop protection guides
Cutworms

Diamondback moth


Flax scouting chart

Flea beetles

Iceberg reports


Lily leaf beetle

Painted lady butterflies
Pea leaf weevil
PMRA Pesticide Label Mobile App

Ticks and Lyme disease


Weather radar


Wind trajectories


Weekly Update – Weather Synopsis

Across the prairies, weather conditions were warmer and wetter than long term average values for the period of June 6-13, 2016The average temperature was 15°C and was approximately 2°C warmer than the previous week. 



Across the prairies, weather conditions were very similar to long term average (LTN) values for the period of June 13-19, 2016. The average temperature was 14 °C and was approximately 1 °C warmer than the previous week. Temperatures in southern MB were 5-6 °C warmer than many locations in AB. 







The Peace River region was wetter than normal while most of southern AB and MB were dryer than normal. 

Soil moisture conditions are wettest in the Peace River region and across southern SK and MB. Southern AB and central SK have the driest soil moisture conditions.



The map below reflects the Accumulated Precipitation for the Growing Season so far for the prairie provinces (i.e., April 1-June 20, 2016):

Compared to last week, overnight temperatures were warmer during the past 7 days.  The map below shows the Lowest Temperatures the Past 7 Days (June 14-20, 2016) across the prairies:

The map below shows the Highest Temperatures the Past 7 Days (June 14-20, 2016):

The updated growing degree day map (GDD) (Base 5ºC, March 1 – June 19, 2016) is below:

While the growing degree day map (GDD) (Base 10ºC, March 1 – June 19, 2015) 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 – Cutworms

Cutworms (Noctuidae) – Please refer to earlier cutworm posts describing scouting tips, monitoring protocols and fact sheets (including cutworm images plus action and economic thresholds).

For Manitobans….The  earlier Insect Update included great photos of dingy and redbacked cutworms plus monitoring tips including how to discern these two species from one another.  Reports of cutworm continued in the current Insect Update.

For Saskatchewanians…. Cutworms were reported in the recent Saskatchewan Insect Report (Issue 3).

For Albertans….. Additional reports of cutworms have occurred throughout the province the past week!  If you find cutworms, please consider using the Alberta Pest Surveillance Network’s “2016 Cutworm Reporting Tool”.  Once data entry occurs, your growers can view the live 2016 cutworm map.

A screen shot of the live map has been retrieved (22Jun2016) below for your reference.


Bertha Armyworm

Bertha armyworm (Lepidoptera: Mamestra configurata– Moths should have appeared in pheromone traps by now since all areas of arable prairie farmland are highlighted either yellow or orange in the map below.






Those monitoring BAW pheromone traps may want to compare trap “catches” to the following reference photo kindly shared by Saskatchewan Agriculture below:

Provincial staff coordinate BAW pheromone trapping across the prairies and summarize cumulative counts in report or map formats:
● Saskatchewanians.… Watch for future Insect Reports.  
● Manitobans.…. Exceedingly low numbers of male moths were intercepted during the first week of monitoring (Insect and Disease Report posted June 15, 2016, prepared by J. Gavloski).  

● Albertans.…..  Refer to the live 2016 map reporting Bertha armyworm pheromone trap interceptions.  A copy of the map (retrieved June 22, 2016) is below for reference.

Weekly Update – Grasshoppers

Grasshoppers (Acrididae) – Previous model predictions related to hatch and nymphal instar development can be reviewed here.  

For the week of June 19, 2016, warm conditions in southeastern Saskatchewan and southern Manitoba were predicted to result in enhanced grasshopper development. Across the prairies, grasshoppers should be between the first and fifth instars. The model predicted that approximately 15% of the population was predicted to be in the first instar, 35% second, 28% third, 13% fourth instar and just under one percent fifth instar.  Development is well ahead of average rates (22% first instar, 14% second instar and 10% third instar). 



In central Saskatchewan, grasshopper development is currently more than two weeks ahead of average development. The following graph shows grasshopper development at Saskatoon based on 2016 data. The model indicates that fifth instar grasshoppers should be present.





Now compare the above with the following graph which illustrates grasshopper development (for Saskatoon) based on long term normal (LTN) data.  The model indicates that  primarily first instars are predicted to be present with only the initial appearance of third instar nymphs. 



The following image showing various stages of the clearwinged grasshopper is provided below – note that adults have wings extending the length of the abdomen whereas nymphs lack wings but develop wing buds that will eventually mature to wings.  


Figure 1. Life stages of Camnulla pellucida  which including eggs, first-fifth instar nymphs and adult (L-R).


Biological and monitoring information related to grasshoppers in field crops is posted by the provinces of ManitobaSaskatchewanAlbertaBritish Columbia 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” – both English-enhanced or French-enhanced versions are available.

Weekly Update – Swede midge

Swede midge (Contarinia nasturtii)  – Reminder – Pheromone traps captured the first swede midge of 2016 between May 25 and 31 in northeastern Saskatchewan.  This is substantially earlier (6-7 weeks) compared to 2014 and 2015. 


The earlier emergence pattern is likely due to the mild winter and warm spring weather combined with adequate moisture levels. Emergence traps indicate a moderate number of swede midge have emerged near Carrot River, Saskatchewan, and producers should monitor their canola fields for damage symptoms

Figure 1. Swede midge infested canola buds which are enlarged with sepals fused together. 




Figure 2.  Swede midge large (~1mm long; yellowish-white) feeding within canola flower.



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.
• 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 Canola Watch article by Dr. Julie Soroka for more information on swede midge and watch for a new Ontario fact sheet produced by Baute et al. 2016.




Note the distribution map of confirmed symptoms and populations of swede midge (red dots) on the Canadian prairies  (Soroka and Andreassen 2015).



Weekly Update – 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.


CSPW 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.


The map below reflects CSPW densities observed in 2015.  Growers situated within or adjacent to areas of the map highlighted yellow, orange and red will need to be scouting with a sweep-net as their canola fields initiate flowering.






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.

Weekly Update – Cereal leaf beetle

Cereal leaf beetle (Oulema melanopus) – Back in May, the cereal leaf beetle (CLB) bioclimatic model was utilized to help predict when eggs and larvae might appear in fields along with its parasitoid, Tetrastichus julis

Recall the following (posted May 25, 2016) – Predicted dates of peak emergence of CLB eggs and larvae:





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.



Monitoring:
Give priority to following factors when selecting monitoring sites:
   □ Choose fields and sections of the fields with past or present damage symptoms.
   □ Choose fields that are well irrigated (leaves are dark green in color), including young, lush crops. Areas of a field that are under stress and not as lush (yellow) are less likely to support CLB. 
   □ Monitor fields located along riparian corridors, roads and railroads. 
   □ Survey field areas that are close to brush cover or weeds, easy to access, or are nearby sheltered areas such as hedge rows, forest edges, fence lines, etc.

Focus your site selection on the following host plant priorities:
   □ First – winter wheat. If no winter wheat is present then;
   □ Second – other cereal crops (barley, wheat, oats, and rye). If no cereal crops are present then;
   □ Third – hay crops. If no hay crops or cereal crops are present then;
   □ Fourth – ditches and water corridors


Sweep-net Sampling for Adults and Larvae:
 ● A sweep is defined as a one pass (from left to right, executing a full 180 degrees) through the upper foliage of the crop using a 37.5 cm diameter sweep-net. 
 ● A sample is defined as 100 sweeps taken at a moderate walking pace collected 4-5 meters inside the border of a field.  
 ● At each site, four samples should be collected, totaling 400 sweeps per site.  The contents of each sample should be visually inspected for life stages of CLB and all suspect specimens should be retained for identification.  
 ● Because the CLB larvae are covered in a sticky secretion, they are often covered in debris and are very difficult to see within a sweep-net sample. 
 ● To help determine the presence of CLB, place the contents of the sweep net into a large plastic bag for observation.

Visual Inspection:
Both the adults and larvae severely damage plants by chewing out long strips of tissue between the veins of leaves (Fig. 2), leaving only a thin membrane. When damage is extensive, leaves turn whitish. 

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 – Alfalfa weevil

Alfalfa Weevil (Hypera postica)  Earlier predictive model outputs can be reviewed by searching the Blog for “Alfalfa weevil” or use the Label Index located to the right of the screen to sort and review all “Alfalfa weevil” posts for 2016.


Reminder – 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).




Economic thresholds for Alfalfa weevil (adapted from Soroka 2015) vary by crop type (hay or seed), area fed upon and larval densities.

In hay fields, forage losses can be economic if one or more of the following symptoms are noted:
● if 25-50 % of the leaves on the upper one-third of the stem show damage, or
● if 50-70% of the terminals are injured, or
● if 1 to 3 third or fourth instar larvae occur per stem (with shorter stems having lower economic thresholds and 3 or more larvae requiring treatment no matter what the alfalfa height), or 
● 20-30 larvae per sweep occur when 12% leaf loss is acceptable.
● Also consider these two points:
      1. Early cutting of the first growth of alfalfa or insecticide treatment will reduce alfalfa weevil populations.
      2. If the hay crop value is high and weevil injury is seen or 2 or more larvae per stem reappear in regrowth after cutting, insecticide may be necessary (if a second cut is anticipated). 


In alfalfa seed fields:
● Economic thresholds are 20-25 third to fourth instar larvae per sweep or 35-50% of the foliage tips showing damage. 
● Thresholds increase with the height of the alfalfa, and decrease in drought conditions. 
● Also know that several small wasps parasitize alfalfa weevil larvae and adults, and in the past these natural control agents kept the weevil in check in most years. One of these wasps, Bathyplectes curculionis (Thomson), parasitizes alfalfa weevil in Alberta and Saskatchewan, and is now found in Manitoba.

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 (June 15, 2016, prepared by John Gavloski and Pratisara Bajracharya).

– Saskatchewan’s Insect Report which contains a reminder for cutworms (Issue 3, prepared by Scott Hartley).
– Watch for Alberta Agriculture and Forestry’s Call of the Land for updates from Scott Meers  who recently provided an update (posted on June 16, 2016including cabbage seedpod weevil on early canola in southern Alberta but also incidences of blister beetlesred turnip beetles, and  small scarab beetle larvae.

Weekly Update – Previous Posts

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


Canola scouting chart
Wind trajectories
Flea beetles in canola
Predicted cereal leaf beetle development
Predicted lygus bug development
Predicted wheat midge development
Pea leaf weevil monitoring
Crop protection guides
Using Environment Canada’s radar maps to follow precipitation events
Iceburg reports

Monarch migration

Insect of the Week – Cotesia margeniventris

Cotesia margeniventris (parasitoid)

Last year, the focus of the 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] 

This week’s Insect of the Week is Cotesia marginiventris (sorry, no common name), a braconidid wasp parasitoid. Female C. marginiventris lay their eggs in the larvae of cabbage looper, black cutworm, corn earworm, variegated cutworm, armyworm and fall armyworm.


For more information about C. marginiventris, the pests it controls and other important crop and forage insects, see the new Field Crop and Forage Pests and their Natural Enemies in Western Canada – Identification and Management Field Guide for identification, life cycle and conservation options (download links for field guide available on the Insect of the Week page).

Cotesia marginiventris parasitoidizing beet armyworm larva.
Photo cc-by-nc Debbie Waters, University of Georgia, Bugwood.org


Weekly Update

Greetings!

A downloadable PDF version of the complete Weekly Update for Week 8 (June 22, 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 – Small scarab beetle

Small scarab beetle (Coleoptera: Aphodius distinctus) – This is the time of summer that farmers will be seeing larvae of a small scarab beetle (Aphodius distinctus) in their fields.  There have been scattered reports each June of large numbers of beetle grubs in crops associated with crop damage (e.g., canola, corn, dry bean, onion, pea).


Please help researchers compile information related to this species so they might confirm its pest status!  Information is posted about the beetle and the survey.  Here’s how you can help:


1. Please send reports of high white grub densities and associated crop damage to Kevin.Floate@agr.gc.ca (403-317-2242). 


2. Live larvae accompanied by the following field information would be extremely helpful please – contact Dr. Kevin Floate if you have a sample!


3. Include answers to the following so the pest status for this species can be ascertained:  
     – Previous crop?
     – Legal land location or latitude+longitude?
     – Irrigated or not?
     – Was composted manure added this spring?
     – Surface residue in spring?

Weekly Update – Crop reports

Crop reports are produced by:

– Manitoba Agriculture, Rural Development (June 20, 2016)
– Saskatchewan Agriculture Crop Report (June 13, 2016)

– Alberta Agriculture and Forestry (for June 14, 2016)

Insect of the Week – Grasshopper

The grasshopper (Packard, clearwinged, migratory and two-striped) is this week’s Insect of the Week  (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). 

Insect of the Week – Cabbage seedpod weevil

The cabbage seedpod weevil (Ceutorhynchus obstrictus (Marsham)) is this week’s Insect of the Week  (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).