Weekly Update

Jennifer Otani, David Giffen, Ross Weiss, Serge Trudel, Kelly Turkington, Erl Svendsen, Shelley Barkley, Owen Olfert and Meghan Vankosky
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Week 6

Greetings!

Things are starting to get busy now that seeding is well underway across the prairies!  In-field scouting begins as soon as that seed is in the ground!

Access the complete Weekly Update either as a series of Posts for Week 06 (May 16, 2019) OR a downloadable PDF version.  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!

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Weather synopsis

Ross Weiss, David Giffen, Owen Olfert and Meghan Vankosky
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Week 6

Weather synopsis – This past week (May 8-15, 2019) the average temperature was approximately 1 °C cooler than normal (Fig. 1). The warmest temperatures were observed in AB and with conditions much cooler in SK and MB.  

Figure 1.  Average Temperature (°C) across the Canadian prairies the past seven days (May 8-15, 2019).

Average 30-day temperatures were approximately 2 °C cooler than average (Fig. 2). Across the prairies, average temperatures (April 9-May 6)  were 0 to -3 °C below normal (Fig. 3). 

Figure 2.  Mean temperature differences from Normal across the Canadian prairies from April 16-May 13, 2019.
Image has not been reproduced in affiliation with, or with the endorsement of the 
Government of Canada and was retrieved (16May2019).  
Access the full map at http://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=true
Figure 3.   Average Temperature (°C) across the Canadian prairies the past 30 days (April 15- May 15, 2019).

Seven-day cumulative rainfall indicated that minimal rain was observed across large areas in AB and MB. Most locations reported less than 5mm (Fig. 4). 

Figure 4.  Cumulative precipitation observed the past seven days across the Canadian prairies (May 8-15, 2019).

Across the prairies, rainfall amounts for the past 30 days (April 15-May 15, 2019) have been approximately 50% of normal (Fig. 5).  Growing season rainfall amounts have been well below average for most of the prairies. Only two areas, southern SK and the Peace River region were the only two areas that had normal to above normal rainfall (Fig. 6). 

Figure 5.  Percent of Average precipitation across the Canadian prairies the past 30 days (Up to May 15, 2019).
Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (16May2019).  
Access the full map at http://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=true
Figure 6. Cumulative precipitation observed the past 30 days across the Canadian prairies (April 15-May 15, 2019).

Soil moisture values are low across most of the prairies (Fig. 7). 

Figure 7.  Modeled soil moisture (%) across the Canadian prairies (up to May 15, 2019).

The growing degree day map (GDD) (Base 5 ºC, April 1-May 15, 2019) is below (Fig. 8):

Figure 8.  Growing degree day (Base 5 ºC) across the Canadian prairies for the growing season (April 1-May 15, 2019).
Image has not been reproduced in affiliation with, or with the endorsement of the 
Government of Canada and was retrieved (16May2019).  
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. 9):

Figure 9.  Growing degree day (Base 10 ºC) across the Canadian prairies for the growing season (April 1-May 15, 2019).
Image has not been reproduced in affiliation with, or with the endorsement of the 
Government of Canada and was retrieved (16May2019).  
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 -10 to 2 °C in the map below (Fig. 10).

Figure 10.  Lowest temperatures (°C) observed across the Canadian prairies the past seven days (May 8-15, 2019).
Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (16May2019).  
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 may wish to bookmark the AAFC Drought Watch Maps for the growing season.

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Wind Trajectories

Ross Weiss, Meghan Vankosky and Serge Trudel
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Week 6

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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Prairie Crop Disease Monitoring Network

Kelly Turkington and prairiepest_admin
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Week 6

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 14, 2019, Weekly Cereal Rust Risk Report: 

Wind trajectory and cereal rust risk assessment and need for in-crop scouting in the Prairie region, May 14, 2019

1.  Pacific Northwest – Given limited stripe rust development in the PNW, a low number of recent wind trajectories from the PNW, cool Prairie weather conditions, and early stages of Prairie crop development, as of May 14, 2019, the risk of stripe rust appearance from the PNW is limited and scouting for this disease is not urgent.  

2.  Texas-Nebraska corridor – Although leaf and stripe rust development continues in this corridor, the disease is mainly affecting the lower canopy at generally low levels.  There has been a low number of recent wind trajectories from this area, cool Prairie weather conditions, and early stages of Prairie crop development.  As of May 14, 2019 the risk of leaf and stripe rust appearance from the Texas-Nebraska corridor is low 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.

4.  Access the full downloadable report.

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Flea beetles

Jennifer Otani
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Week 6

Flea Beetles (Chrysomelidae: Phyllotreta species)– As newly seeded stands begin to emerge, the need for in-field scouting increases.  Review Wk05 for flea beetle information, visual guides to help estimate percent of cotyledon damage, and links to the Insect Field Guide.  

This week we also link to Canola Watch which released flea beetle scouting and management tips for canola.  Provincial entomologists, flea beetle researchers and Canola Council of Canada specialists all provided input into this article.

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.

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Cutworms

Jennifer Otani
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Week 6

Cutworms (Noctuidae) – Still important this week to scout for cutworms!! Access Wk05 for help!  

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Cereal leaf beetle

Ross Weiss, David Giffen, Owen Olfert and Meghan Vankosky
Categories
Week 6

Cereal leaf beetle (Oulema melanopus) – The CLB model was run for Lethbridge AB and projected to June 15, 2019 (Fig. 1).  The cereal leaf beetle model indicates that eggs may begin to hatch later next week Lethbridge.

Figure 1.  Projected predicted status of cereal leaf beetle populations near Lethbridge 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”.

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Alfalfa weevil

Ross Weiss, David Giffen, Owen Olfert and Meghan Vankosky
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Week 6

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 (Fig. 1) and Swift Current SK (Fig. 2) were projected to June 15, 2019.  Model output indicates that initial hatch should occur late next week in fields near Brooks. Hatch should be 5-7 days later in the Swift Current region. Compared to last year’s runs for Swift Current, development is predicted to be 10 days later than 2018. Compared with long term normal weather data, egg development is 1 – 2 days later than average. 

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.

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Predicted grasshopper development

Ross Weiss, David Giffen, Owen Olfert and Meghan Vankosky
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Week 6

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).  

Compared to last week, near normal temperatures have resulted in expected development of grasshopper eggs.  This week, as of May 15, 2019, predicted development was 63% and is similar to long term average values (Fig. 1).  

Figure 1.  Predicted grasshopper (Melanoplus sanguinipes) embryological development acrossthe Canadian prairies as of May 15, 2019. 

Model runs for Lethbridge (Fig. 2) and Saskatoon (Fig. 3) were projected to June 15, 2019. Results indicated that eggs should begin to hatch next week. Model predictions, based on long term normal weather data predict that initial hatch near Saskatoon should occur on May 25th.

Figure 2. Predicted status of Melanoplus sanguipes populations near Lethbridge AB as of  May 15, 2019.  
Figure 3.  Predicted status of Melanoplus sanguipes populations near Saskatoon SK as of  May 15, 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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Pea leaf weevil

Ross Weiss, David Giffen, Owen Olfert and Meghan Vankosky
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Week 6

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 at the end of May. 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.

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Scouting Charts – Canola and Flax

Jennifer Otani
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Week 6

Reminder – We have updated the field scouting charts so they now link to pages within the 2018 version of the Insect Field Guide. 

We offer TWO generalized insect pest scouting charts to aid in-field scouting on the Canadian prairies:

1. CANOLA INSECT SCOUTING CHART

2018_ScoutingChart_Canola

2. FLAX INSECT SCOUTING CHART

2018_ScoutingChart_Flax

These charts feature hyperlinks directing growers to downloadable PDF pages within the “Field crop and forage pests and their natural enemies in western Canada: Identification and management field guide“.

Whenever possible, monitor and compare pest densities to established economic or action thresholds to protect and preserve pollinators and beneficial arthropods. Economic thresholds, by definition, help growers avoid crop losses related to outbreaking insect pest species.

Good luck with your scouting!

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Field Heroes

Jennifer Otani
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Week 6

The Field Heroes campaign continues to raise awareness of the role of beneficial insects in western Canadian crops.

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 valuable arthropods occurring in field crops.

Have you seen the “Check the Net” infographics that helps growers understand just how many organisms are present in cereals, oilseeds, and pulses and that ONLY A SMALL PROPORTION are considered economic pests?  A great many of the other insects, spiders, and mites are beneficial organisms that work to regulate crop pests!  Protect and enhance their impact on crop pests by performing in-field assessments and use economic thresholds to help decide when control is warranted and find out more about the Cereal Avengers, Oilseed Avengers and Pulse Avengers!

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

Be sure to follow @FieldHeroes on Twitter for practical tips and information.

Thanks to Western Grains Research Foundation for their support of this important campaign. This initiative has been made possible through the support and advice of enthusiastic members of the Prairie Pest Monitoring Network.

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Weather Radar

Jennifer Otani
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Week 6

Remember – If your fields are near one of Environment Canada’s PRAIRIE Radar Stations, consider accessing weather radar maps in video format to access either the past 1 OR 3 hours of precipitation events displayed as spatio-temporal maps.  These maps can help growers review where and how much precipitation fell nearby and can help when trying to time pesticide applications.

Screen shots of Environment Canada’s webpages are below for reference and red text and arrows have been added to help you navigate the webpage.

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Provincial Insect Pest Reports

James Tansey, John Gavloski and Scott Meers
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Week 6

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 include updates from Dr. John Gavloski.

• Saskatchewan‘s Crops Blog Posts includes a segment on “Early season scouting of cutworms” by Sara Doerksen posted for April 2019. Watch for 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 report links

Jennifer Otani
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Week 6

Crop reports are produced by:

The following crop reports are also available:

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Invasive species: Lily leaf beetle (Lilioceris lilii) and its natural enemy, Tetrastichus setifer

Jennifer Otani
Categories
Week 6
Lily leaf beetle (Lilioceris lilii) adult – Shelley Barkley

The lily leaf beetle (Lilioceris lilii) is a native of Europe and was originally found in Canada at Montreal in 1945. Since then, it has spread throughout Eastern Canada and has now established itself as far west as Alberta. Long distance movement of the beetle is facilitated by movement of plant material; locally, they move on their own as they are strong flyers.

The lily leaf beetle lays its eggs and develops only on true lilies (Tiger, Easter, Asiatic and Oriental lilies) and fritillaries. They can feed (but not develop) on other perennials like lily-of-the-valley.  Adult and larval feeding will ruin true lilies. The feeding damage can be so severe that many gardeners have removed lilies from their landscapes.  

The adult beetle overwinters in the soil or leaf litter, not necessarily near host plants. They emerge on the first warm spring days and will begin feeding on the early emerging lilies, as early as mid-April on the Prairies. Shortly after emergence, they start to mate and lay orange eggs in rows of 3-12 on the undersides of the lily leaves or on the emerging lily shoots (late April to early May). Egg laying (up to 450 per female) can continue well into July. Eggs will hatch in 4-8 days.

The larva is a soft, hump-backed, orange to brownish slug-like animal with a black head and legs. For protection from predation, desiccation and camouflage, it covers its body with a layer of its own fecal matter. The larval stage most destructive phase of the beetle’s life cycle, as larvae feed for 16-24 days. They devour leaves leaving only the plant stems, and chew into flower buds. Larvae drop to ground to pupate and emerge as adults 16-22 days later.

Tetrastichus setifer, a small parasitoid wasp (harmless to humans), is being introduced as biological control agent for the beetle. T. setifer overwinters in the soil in a cocoon. It then emerges in the spring and the female will lay up to nine eggs in one lily leaf beetle larva. She can lay eggs in all four larval instars of the lily leaf beetle.

There have been successful T. setifer releases in Ottawa with establishment and good suppression of lily leaf beetles. Releases have been done in gardens in Manitoba and Quebec as well natural sites in Quebec where the native lilies Lilium canadense, and Lilium michiganense grow. Successful establishment of T. setifer in the natural locations is uncertain at this time. Recently, there have been releases in Calgary, Alberta and Olds, Alberta. In 2018 additional releases were made in 2 gardens in Brooks, Alberta.

Tetrastichus setifer on Lily leaf beetle larva – Shelley Barkley

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.

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