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Thursday, 28 May 2020

Weekly Update (May 28, 2020; Wk 05) Otani, Weiss, Rounce, Trudel, Svendsen, Turkington, Olfert, Barkley, Vankosky

Scouting for insect pests in field crops needs to step up a notch now across the prairies. Several of the economic pests Canadian growers contend with are now developing into the more damaging stages of their lifecycles.

Access information to support your in-field insect monitoring efforts in the complete Weekly Update either as a series of Posts for Week 5 OR a downloadable PDF.

Stay Safe!


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!
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Weather synopsis

Weather synopsis –  This week, May 19-25, 2020, temperature and moisture conditions varied significantly across the prairies (Tables 1 and 2). Average 7-day temperatures were much warmer than normal in Manitoba (Fig. 1 and 3) while rainfall amounts were well above average across Alberta (Table 1).  Average 30-day (April 26-May 25, 2020) temperatures were slightly warmer than average across most of the prairies (Fig. 2). Temperature anomalies indicated that Saskatchewan was normal to above normal; Alberta and Manitoba 30-day temperature anomalies were normal to below normal (Fig. 3). 



Figure 1. Observed average temperatures across the Canadian prairies for the past seven days (May 19-25, 2020).

Figure 2. Observed average temperatures across the Canadian prairies for the past 30 days (April 26-May 25, 2020).

Figure 3. Mean temperature difference from Normal across the Canadian prairies the past 30 days (April 26-May 25, 2020).
Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (27May2020).  

This past week significant rainfall was reported across most of Alberta and western Saskatchewan (Table 1 and Fig. 4). Eastern Saskatchewan has had the lowest 30-day cumulative rainfall amounts (Fig. 5). The recent rain has resulted in above normal rainfall (compared to long term normal) for most of Alberta (Fig. 6). Conditions continue to be dryer than normal across most of Saskatchewan and Manitoba.  Rainfall amounts for the past 30 days (Fig. 5) have been approximately 125% of normal (Fig. 6).  
Figure 4. Observed cumulative precipitation across the Canadian prairies for the past seven days (May 19-25, 2020).

Figure 5. Observed cumulative precipitation across the Canadian prairies for the past 30 days (April 26-May 25, 2020).

Figure 6. Percent of average precipitation the past 30 days (April 26-May 25, 2020).
Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (27May2020).  

The growing degree day map (GDD) (Base 5 ºC, April 1-May 25, 2020) is below (Fig. 7):
Figure 7. Growing degree day map (Base 5 °C) observed across the Canadian prairies for 
the growing season (April 1-May 25, 2020).
Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (28May2020).  
Access the full map at http://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=true&reset=1588297059209

The growing degree day map (GDD) (Base 10 ºC, April 1-May 25, 2020) is below (Fig. 8):
Figure 8. Growing degree day map (Base 10°C) observed across the Canadian prairies for 
the growing season (April 1-May 25, 2020).
Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (28May2020).  
Access the full map at http://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=true&reset=1588297059209

The lowest temperatures (°C) observed the past seven days ranged from <-2 to >10 °C in the map below (Fig. 9).
Figure 9. Lowest temperatures (°C) observed across the Canadian prairies the past seven days (May 21-27, 2020).
Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (28May2020).  

The highest temperatures (°C) observed the past seven days ranged from <9 to >27 °C in the map below (Fig. 10).
Figure 10. Highest temperatures (°C) observed across the Canadian prairies the past seven days (May 21-27, 2020).
Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (28May2020).  

The maps above are all produced by Agriculture and Agri-Food Canada.  Growers can bookmark the AAFC Current Conditions Drought Watch Maps for the growing season.  More weather data can be access at the AAFC Drought Watch website, Environment Canada's Historical Data website, or your provincial weather network.
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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 Wk05 (released May 25, 2020).
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Diamondback moth

Diamondback moth (Plutellidae: Plutella xylostella) - Once diamondback moth is present in the area, it is important to monitor individual canola fields for larvae.  Warm growing conditions can quickly translate into multiple generations in a very short period!

Wind Trajectory Updates - Wind trajectory models used to deliver an early-warning system for the origin and destination of migratory invasive species indicated arrival events of air currents potentially carrying migrating diamondback moths from more southerly regions.  Access the Weekly Wind Trajectory Report (released May 25, 2020) to review where wind trajectories originating over Mexico, California, Texas or the Pacific Northwest cross locations in Manitoba, Saskatchewan, and Alberta.

Weekly Pheromone-baited Trapping Results - Early season detection of diamondback moth is improved through the use of pheromone-baited delta traps deployed in fields across the Canadian prairies.  As they become available, moth reporting numbers observed in Alberta, Saskatchewan and Manitoba will be linked here.

Monitoring:
Remove the plants in an area measuring 0.1 m² (about 12" square), beat them on to a clean surface and count the number of larvae (Fig. 1) dislodged from the plant. Repeat this procedure at least in five locations in the field to get an accurate count.
Figure 1. Diamondback larva measuring ~8 mm long.
Note brown head capsule and forked appearance of prolegs on posterior.
Figure 2. Diamondback moth pupa within silken cocoon.

Economic threshold for diamondback moth in canola at the advanced pod stage is 20 to 30 larvae/ 0.1 m² (approximately 2-3 larvae per plant).  Economic thresholds for canola or mustard in the early flowering stage are not available. However, insecticide applications are likely required at larval densities of 10 to 15 larvae/ 0.1 m² (approximately 1-2 larvae per plant).

Figure 3. Diamondback moth.

Biological and monitoring information for DBM is posted by Manitoba Agriculture, Saskatchewan Agriculture, and the Prairie Pest Monitoring Network.  

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

This year the Victoria day long weekend came early (May 16-18, 2020), and so did two of our annual, migratory pests. While the PPMN tracks forward and backward trajectories of high air masses originating in the southern part of North America and arriving to points across the Canadian prairies, the provincial ministries of Alberta, Saskatchewan, and Manitoba coordinate province-wide diamondback moth (DBM) trapping to detect the initial appearance of DBM.  Traps include a pheromone lure used to entice male DBM to a sticky death in order to monitor their arrival across the Canadian prairies.

Early arriving DBM can reproduce on volunteer cruciferous weeds then move to canola as that crop emerges and grows in the spring. This can lead to population increases through the growing season. In some areas of Canada, DBM can produce up to five generations before the winter cold brings an end to their populations.

Recently, AAFC scientists supported by WGRF, have been matching these wind trajectories with the arrivals of DBM and another migratory pest, the aster leafhopper.  The aster leafhopper spreads aster yellows disease, primarily to canola, and can have up to three generations in Canada. AAFC scientists have recently developed a rapid test to determine if an aster leafhopper is infected with aster yellows. In 2020, the COVID-19 pandemic lockdown prevented us from estimating the percentage of infected aster leafhoppers and gaining a better understanding of the risks of aster yellows transmission. Aster leafhoppers and DBM have migrated into Saskatchewan and might also be in Alberta and Manitoba.

Contact Dr. Chrystel Olivier and Dr. Tyler Wist to find out more about the above aster leafhopper  project.



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Alfalfa weevil

Alfalfa Weevil (Hypera postica) – Degree-day maps of base 9 °C are produced to predict the development of Alfalfa weevil (AAW) across the prairies.  The model is updated weekly to help growers time their in-field scouting for second-instar larvae. 

 As of May 25, 2020, the model output indicates that oviposition is well underway and initial hatch has begun in some locations. The following graphs compare development for Winnipeg (Fig. 1) and Lethbridge (Fig. 2).  At Winnipeg, first instar larvae are expected to occur already (Fig. 1) while first instar larvae should begin to appear later this week in southern AB (Fig. 2). 
Figure 1. Predicted alfalfa weevil (Hypera postica) phenology at Winnipeg MB.
Values are based on model simulations (April 1-May 25, 2020).

Figure 2. Predicted alfalfa weevil (Hypera postica) phenology at Lethbridge AB.
Values are based on model simulations (April 1-May 25, 2020).

Based on the alfalfa weevil degree day model (Soroka et al. 2020), AAW development is most advanced across southern SK (Fig. 3). The second map (Fig. 4) presents occurrence of first instar larvae (% of total population). 

Figure 3. Predicted development of populations of alfalfa weevil (Hypera postica) across
the Canadian prairies as of May 25, 2020. 

Figure 4. Predicted percent of alfalfa weevil (Hypera postica) at first instar stage across
the Canadian prairies as of May 25, 2020. 


Monitoring
The larval stage of this weevil feeds on alfalfa leaves in a manner that characterizes the pest as a “skeletonizer” (Fig. 3, lower left).  The green larva featuring a dorsal, white line down the length of its body has a dark brown head capsule and will grow to 9 mm long (Fig. 3, upper right).  

Figure 3.  Developmental stages of the alfalfa weevil (Hypera postica); overwintered adult (upper row L-R), eggs, larvae, larva feeding or "skeletonizing" alfalfa leaf (lower row L-R), pupa within lacey cocoon, pupa, and newly emerged adult.
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. 2018). The guide is available as an English-enhanced or French-enhanced version.
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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 25, 2020, predicted embryonic development (Fig. 1) was 73% (66% last week) and is 5% higher than long term average values.  Development is greatest in a region extending from Winnipeg to Saskatoon to Lethbridge (Fig. 1, Table 1).  

 This week, initial hatch is predicted to occur across most of the southern prairies (Fig. 2, Table 1). The simulation estimates that the hatch, based on the prairie average, is 2.9%. Hatch of grasshopper nymphs was predicted to be most advanced in the region extending from Regina to the U.S. border.  
Figure 1. Grasshopper embryological development (%) based on model simulations using
current environmental conditions (as of May 25, 2020).
Figure 2. Predicted percent of grasshopper (Melanoplus sanguinipes) population at hatching stage across
the Canadian prairies (as of May 25, 2020). 

 Table 1. Predictive model output estimates for M. sanguinipes at selected sites across the Canadian prairies (as of May 25, 2020).
Biological and monitoring information related to grasshoppers in field crops is posted by Manitoba Agriculture, Saskatchewan Agriculture, Alberta Agriculture and Forestry, the BC Ministry of Agriculture and the Prairie Pest Monitoring Network.  Also refer to the grasshopper pages within the "Field Crop and Forage Pests and their Natural Enemies in Western Canada: Identification and management field guide" (Philip et al. 2018) as an English-enhanced or French-enhanced version.
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Cereal leaf beetle

Cereal leaf beetle (Oulema melanopus) - The CLB simulation model will be used to monitor this insect pest's development across the prairies. Weekly temperature data collected across the prairies is incorporated into the simulation model which calculates estimates of development stages based on biological parameters for this species.  

As of May 25, 2020, CLB simulations indicate that oviposition continues and that first instar larvae are beginning to appear (Table 1).  The graph for Winnipeg illustrates occurrence of 1st instar larvae (Fig. 1).

Table 1. Predictive model output estimates for O. melanopus at selected sites across the Canadian prairies (as of May 25, 2020).


Figure 1. Predicted cereal leaf beetle phenology at Winnipeg MB.
Values are based on model simulations (April 1-May 25, 2020).

Manitobans - Dr. John Gavloski is looking for samples of cereal leaf beetle larvae this growing season to determine their range across Manitoba, their population density, and the rate at which larvae are parasitized. Please contact John.Gavloski@gov.mb.ca or @JohnTheBugGuy if you observe cereal leaf beetles in your fields. 

Lifecycle and Damage:
Adult: Adult cereal leaf beetles (CLB) have shiny bluish-black wing-covers (Fig. 4). 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 4. 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. 5).  When the larva completes its growth, it drops to the ground and pupates in the soil. 
Figure 5.  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 "Field crop and forage pests and their natural enemies in western Canada - Identification and management field guide" available as a free downloadable document in either an English-enhanced or French-enhanced version.
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Pea leaf weevil

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

The pea leaf weevil resembles the sweet clover weevil (Sitona cylindricollis) but the former is distinguished by three light-coloured stripes extending length-wise down thorax and sometimes the abdomen.  All species of Sitona, including the pea leaf weevil, have a short snout.  
Figure 1.  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.

Reminder - The 2019 prairie-wide risk map for pea leaf weevils was released in March 2020.  The map is based on the number of feeding notches observed in peas (Fig. 2). 
Figure 2. Estimates of pea leaf weevil (S. lineatus) densities based on feeding notches observed in
peas grown in Alberta and Saskatchewan in 2019.

 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. 
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Field Heroes

The Field Heroes campaign continues to raise awareness of the role of beneficial insects in western Canadian crops. Check the recently updated Field Heroes website for scouting guides, downloadable posters, and videos. Learn about these important organisms at work in your fields!  

New this week - Real Agriculture went live with a weekly Pest and Predators podcast series!
• Access Episode 1 - Do you know your field heroes?
• Access Episode 2 - An inside look at the Prairie Pest Monitoring Network.

Access ALL the Field Heroes links here and be sure to follow @FieldHeroes!



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Ticks and Lyme Disease

When enjoying the outdoors and performing field scouting, also watch for ticks!  Blacklegged (deer) ticks are important because they can carry Lyme Disease.  Continued surveillance activities conducted by Health Canada and the provinces remain important and you can help by identifying / removing / submitting your ticks!

Follow the links to learn more and to submit ticks if you live in British Columbia, Alberta, Saskatchewan, Manitoba, Ontario, or Quebec.

Provincial and territorial information related to Lyme disease is available from the following provinces:
• Alberta
• British Columbia
• Manitoba
• Northwest Territories
• Ontario
• Quebec
• Saskatchewan

In Canada, Lyme disease risk areas exist.  Access this webpage for a full list and view Health Canada's map (Fig. 1).
Figure 1. Screenshot of Health Canada's map of Lyme disease endemic and risk areas in Canada (retrieved 28May2020).
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Provincial Insect Pest Reports

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

• Manitoba's Crop Pest Updates for 2020 are available. Access the May 27, 2020 report. The summary indicates there has been some foliar insecticide applications for both flea beetles and cutworms in Manitoba, but just isolated fields and currently not widespread. 


 •  Alberta Agriculture and Forestry's Agri-News occasionally includes insect-related information. Read about overwintered canola and ground beetles.  

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Crop reports

Click the provincial ministry name below to link to online crop reports produced by:
• Manitoba Agriculture - Other viewing options include subscribing to receive or access a PDF of May 26, 2020 report.
• Saskatchewan Agriculture  or access a PDF of May 19-25, 2020 report.
• Alberta Agriculture and Forestry or access a PDF of May 19, 2020 report.

The following crop reports are also available:
• The United States Department of Agriculture (USDA) produces a Crop Progress Report (read the May 26, 2020 edition).
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Monarch migration

We again track the migration of the Monarch butterflies as they move north by checking the 2020 Monarch Migration Map!  A screen shot of the map showing reported first sightings of adults is below as reference (retrieved 28May2020) but follow the hyperlinks to check the interactive map! 

 Notice that the first 2020 monarch spotted on the Canadian prairies was this week near Pincher Creek AB!


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.  
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Previous posts

Click to review these earlier 2020 Posts:

• 2019-2020 Risk and forecast maps

• Bookmark prairie provincial insect pest pages (Wk02)

• Crop protection guides (Wk02)

 • Cutworms (Wk02)

 • Flea beetles (Wk02)

 • Seeking beetle data please! (Wk03)

 • Scouting charts - canola and flax (Wk02)
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Wednesday, 27 May 2020

Prairie Crop Disease Monitoring Network - Turkington

The Prairie Crop Disease Monitoring Network (PCDMN) represents the combined effort of  prairie pathologists working together to support in-field disease management in field crops.  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.  Read the OVERVIEW describing the collaborative nature of this effort and the methods employed.  

 Wind trajectory and cereal rust risk assessment and need for in-crop scouting in the Prairie region, May 19-25, 2020


1. Pacific Northwest – There were a relatively high number of reverse wind trajectories that passed over the PNW region and into the prairies.  Locations with the highest number of days with reverse trajectories from the PNW included: Beiseker (4), Lethbridge (6), Olds (3), Sedgewick (3), and Vegreville (3), AB; Gainsborough (3), Grenfell (3), Kindersley (3), North Battleford (4), Saskatoon (3), Tisdale (3) and Unity (3), SK; and Brandon (3), MB (Table 1). However, currently there is limited stripe rust development in the PNW, cool dry conditions in some Prairie regions, and early stages of Prairie crop development.  Thus, as of May 25, 2020 the risk of stripe rust appearance from the PNW is limited and scouting for this disease is not urgent.  However, locations with 3-6 reverse trajectory events from the PNW may be at a slightly increased stripe rust risk, especially for winter wheat crops. 

2. Texas-Oklahoma corridor – Currently, there is limited leaf and stripe rust development in this corridor.  Moreover, there were a relatively low number of recent wind trajectories from this area for most prairie locations, cool dry conditions in some Prairie regions, and early stages of Prairie crop development.  Thus, as of May 25, 2020 the risk of leaf and stripe rust appearance from the Texas-Oklahoma corridor is limited and scouting for these diseases is not urgent.  It should be noted that crops in Texas are at or approaching maturity with harvesting occurring in many areas.  In Oklahoma the wheat crop is progressing towards maturity in most regions of the state except for the northwest, while rust development is generally limited.  Thus, this region will progressively represent a less critical source of cereal rust inoculum for movement into the Prairie region from late May and throughout June 2020.

3. Kansas to Nebraska corridor – Currently, there is some leaf and stripe rust development in Kansas, but not in Nebraska.  Moreover, there were a relatively low number of recent wind trajectories from this area for most prairie locations, cool dry conditions in some Prairie regions, and early stages of Prairie crop development.  Thus, as of May 25, 2020 the risk of leaf and stripe rust appearance from the Kansas-Nebraska corridor is limited and scouting for these diseases is not urgent. However, there were Prairie locations with 3-6 days with reverse trajectory events from the Kansas/Nebraska region for May 19-25, 2020 and these included: Gainsborough (6), Grenfell (3), Naicam (3), Regina (4), Yorkton (3), and Tisdale (3), SK; Brandon (4), Carman (4), Dauphin (3), Portage (3), Russell (5), and Selkirk (3), MB.  Thus, rust risk may be slightly increased for these areas, especially for winter wheat crops.

4. Where farmers or consultants noticed stripe rust development on winter wheat in the fall of 2019, 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.
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