Weekly Update

Jennifer Otani, David Giffen, Ross Weiss, Serge Trudel, Kelly Turkington, Erl Svendsen, Owen Olfert and Meghan Vankosky
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Week 5

Greetings!

A busy week – seeding is underway across the prairies!  Our many field crop entomologists and their integral cooperators are busy deploying various insect monitoring equipment in fields too. 

This week marks the return of the Insect of the Week for the 2019 growing season!  The initial four weeks will feature invasive species of insects then we will transition to arthropod doppelgangers in an effort to support in-field scouting efforts with identification tips.

The Prairie Pest Monitoring Network is also excited to support the new Prairie Crop Disease Monitoring Network (PCDMN) by promoting their 2019 Cereal Rust Risk Report.  This is a new initiative and reports will be available to support in-field scouting.

Access the complete Weekly Update either as a series of Posts for Week 05 (May 9, 2019) OR a downloadable PDF version is available.

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

Ross Weiss, David Giffen, Owen Olfert and Meghan Vankosky
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Week 5

Weather synopsis – Daily average temperatures continue to be cooler than normal for the early growing season. This past week (April 30-May 7, 2019), the average temperature (0.5 °C) was approximately 6 °C cooler than normal (Fig. 1). The warmest temperatures were observed in southern AB and southeastern SK (Fig. 1).  Average 30-day temperatures were well below normal (Fig. 3). Across the prairies, average temperatures (April 9-May 6)  was 0 to -3 °C below normal (Fig. 2). 

Figure 1.  Average Temperature (°C) across the Canadian prairies the past seven days (April 30-May 7, 2019).
Figure 2.  Average Temperature (°C) across the Canadian prairies the past 30 days (April 7-May 7, 2019).
Figure 3.  Mean temperature differences from Normal across the Canadian prairies from April 9-May 6, 2019.
Image has not been reproduced in affiliation with, or with the endorsement of the 
Government of Canada and was retrieved (09May2019).  
Access the full map at http://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=true

Seven day cumulative rainfall shows that minimal rain was observed across large areas in MB and SK (Fig. 4). Rainfall (30 day accumulation) amounts (Fig. 5) have been well below average for most of the prairies (66% of average) (Fig. 6). Rainfall amounts across southern SK are normal to above normal (Fig. 6). 

Figure 4. Cumulative precipitation observed the past seven days across the Canadian prairies (April 30-May 7, 2019).
Figure 5. Cumulative precipitation observed the past 30 days across the Canadian prairies (April 7-May 7, 2019).
Figure 6. Percent of average precipitation across the Canadian prairies the past 30 days (as of May 8, 2019).
Image has not been reproduced in affiliation with, or with the endorsement of the
Government of Canada and was retrieved (09May2019).  
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 large generally low.

Figure 7.  Modelled soil moisture (%) across the Canadian prairies as of May 7, 2019.

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

Figure 8.  Growing degree day (Base 5 ºC) across the Canadian prairies for the growing season (April 1-May 6, 2019).
Image has not been reproduced in affiliation with, or with the endorsement of the 
Government of Canada and was retrieved (09May2019).  
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, March 1 – June 18, 2017) is below:

Figure 9. Growing degree day (Base 10 ºC) across the Canadian prairies for the growing season (April 1-May 6, 2019).
Image has not been reproduced in affiliation with, or with the endorsement of the 
Government of Canada and was retrieved (09May2019).  
Access the full map at http://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=true
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Wind Trajectories

Ross Weiss, Meghan Vankosky and Serge Trudel
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Week 5

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:

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2018 Insect Field Guide

Jennifer Otani
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Week 5

Get your copy of the newly updated version of the Insect Field Guide!

Field Crop and Forage Pests and their Natural Enemies in Western Canada: IDENTIFICATION AND MANAGEMENT FIELD GUIDE

Find links to download the FREE Insect Field Guide.

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Cutworms

Jennifer Otani
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Week 5

Cutworms (Noctuidae) – A field guide is available to help growers scout and manage Cutworms.  Cutworm Pest of Crops is available for free in either English or French and is posted on the Cutworm Field Guide page!  

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

In 2018, the Insect of the Week featured two economically important species of cutworms and some of the important natural enemies that help regulate these pests:

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

CutwormSeasonalChart_Floate

For Albertans….. If you find cutworms, please consider using the Alberta Pest Surveillance Network’s “2019 Cutworm Reporting Tool” then view the live 2019 cutworm map which is updated daily.

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Flea beetles

Jennifer Otani
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Week 5

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

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

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

Figure 1. Canola cotyledons with various percentages of leaf area consume owing to flea beetle feeding damage (Photo: Soroka & Underwood, AAFC-Saskatoon).
Figure 2.  Percent leaf area consumed by flea beetles feeding on canola seedlings (Photo: Soroka & Underwood, AAFC-Saskatoon).

Refer to the flea beetle page from the “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.

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Alfalfa weevil

Ross Weiss and Meghan Vankosky
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Week 5

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. 

AAW model runs indicate that oviposition should have begun in the Brooks (Rosemary) AB (Fig. 1) and Regina SK regions (Fig. 2).  Note that this week’s cool temperatures have reduced oviposition rates (based on model predictions). 

Figure 1. Predicted status of alfalfa weevil populations near Swift Current SK as of May 7, 2019.
Figure 2. Predicted status of alfalfa weevil populations near Swift Current SK as of May 7, 2019.

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.

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Pea leaf weevil

Ross Weiss and Meghan Vankosky
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Week 5

Pea Leaf Weevil (Sitona lineatus) – The PLW model was run for Red Deer AB (Fig. 1) and Saskatoon SK (Fig. 2). The predictive model outputs suggest that PLW adults are active but oviposition has not begun. 

Figure 1. Predicted status of pea leaf weevil populations near Red Deer as of  May 7, 2019. 
Figure 2. Predicted status of pea leaf weevil populations near Saskatoon SK as of May 7, 2019.

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.

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Cereal leaf beetle

Ross Weiss and Meghan Vankosky
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Week 5

Cereal leaf beetle (Oulema melanopus) – The cereal leaf beetle model indicates that oviposition is well underway in Lethbridge AB as of May 7, 2019 (Fig. 1).

Figure 1.  Predicted status of cereal leaf beetle populations near Lethbridge AB as of April 30, 2019

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”.

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Predicted grasshopper development

Ross Weiss, David Giffen, Owen Olfert and Meghan Vankosky
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Week 5

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).  

This week, cool temperatures this week were predicted to result in minimal embryological development. As of May 7, 2019, predicted development was 60% and is similar to long term average values (Fig. 1). As embryological development approaches 100%, scouting for  nymphs of pest species of grasshoppers should begin.

Figure 1.  Predicted grasshopper (Melanoplus sanguinipes) embryological development across the Canadian prairies as of May 7, 2019. 

Reminder – The Prairie Pest Monitoring Network’s 2019 Grasshopper Forecast Map was released in March.  Review all the current risk and forecast maps by linking here.  While spring temperatures, soil moisture conditions, and precipitation can all have an impact on overwintered grasshopper eggs, areas highlighted orange or red in the 2019 forecast map should be vigilant this spring by performing in-field scouting to assess nymph densities.

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 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.

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Provincial Insect Pest Reports

James Tansey, John Gavloski and Scott Meers
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Week 5

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 will be posted here and includes updates from Dr. John Gavloski.

• Saskatchewan‘s Crop Production News for 2019 will be posted here and frequently includes updates from Dr. James Tansey and Mr. Carter Peru.

•  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.

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Crop reports

Jennifer Otani
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Week 5

Crop reports are produced by:

The following crop reports are also available:

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Invasive species: Brown marmorated stink bug

Jennifer Otani
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Week 5

This week’s Insect of the Week is the brown marmorated stink bug (Halyomorpha halys). Stink bugs get their name from the foul odour they release when threatened. Brown marmorated stink bug is not known to be established in the Prairies, but the species has been found in the Southern Interior of BC, in Ontario and Quebec. Feeding causes damage to seeds and seed pods, reducing yield. Nymphs and adults prefer field corn and soybean, but infestations have been reported on rape, pea, sunflower and cereals in the USA. They have also been known to attack tree fruits, berries, vegetables and many ornamental trees and shrubs.

Brown marmorated stink bug – adult (CC-BY 2.0 Katja Schulz)

Additional information and fact sheets for this insect have been posted by Ontario Ministry of Agriculture, Food, and Rural Development, and BC Ministry of Agriculture and Seafood. You can also check out our Insect of the Week page.

This insect is featured in our Field Crop and Forage Pests and their Natural Enemies Field Guide which is available for download from the Insect Field Guide page. 

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Prairie Crop Disease Monitoring Network (PCDMN)

Kelly Turkington and prairiepest_admin
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Week 5

New for 2019 – 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 7, 2019, Weekly Cereal Rust Risk Report: 

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

2. Texas-Nebraska corridor – Given limited leaf and stripe rust development in this corridor, a relatively low number of recent wind trajectories from this area, cool Prairie weather conditions, and early stages of Prairie crop development, as of early May the risk of leaf and stripe rust appearance from the Texas-Nebraska corridor is limited and scouting for these diseases is not urgent.  

3. 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.

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