Greetings!
Access the complete Weekly Update either as a series of Posts for Week 07 (May 23, 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.
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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:
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, 2019, Weekly Cereal Rust Risk Report:
Wind trajectory and cereal rust risk assessment and need for in-crop scouting in the Prairie region, May 21, 2019.
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 early stages of Prairie crop development, as of May 21, 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 early stages of Prairie crop development. Thus, as of May 21, 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 this corridor, it is at low-moderate levels and mainly in the middle portions of crop canopies, recent moisture conditions may promote further development. There have been a low number of recent wind trajectories from this area, cool and relatively dry Prairie weather conditions, and early stages of Prairie crop development. Thus, as of May 21, 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.
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.
This week, May 15-21, 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. This past week the average temperature was approximately 2.5 °C cooler than normal (Fig. 2). The warmest temperatures were observed in central AB, southeast SK and southwest MB (Fig. 2).
Average 30 day temperatures were approximately 3 °C cooler than average (Fig. 3). Across the prairies, average temperatures (April 23 – May 20, 2019) were 2 to -3 °C below normal with central SK having temperatures that were 3 to 4 °C cooler than average with well below average temperatures occurring in a large area of central SK.
This week (May 15-21, 2019), the seven-day cumulative rainfall indicated that minimal rain was observed across large areas of SK (Fig. 4). Most locations reported less than 5 mm. Wetter conditions were reported in a corridor between Lethbridge and Calgary AB.
Across the prairies, rainfall amounts for the past 30 days (April 21-May 21, 2019) have been approximately 50% of normal (Fig. 5). Rainfall in southwest SK has increased. Between Brandon MB and Lloydminster SK 30-day rainfall amounts are well below average (Fig. 5). Growing season rainfall (April 1 – May 21) amounts have been well below average for most of the prairies, particularly in west central SK and eastern regions of AB (Fig. 6). For this growing season, almost all of the prairies have received rainfall that is 85 percent or less than average (Fig. 7).
Soil moisture values are low across most of the prairies. Near normal soil moisture is predicted to occur in an area extending from Swift Current, west to Lethbridge and north to Edmonton and Grande Prairie (Fig. 8).
The growing degree day map (GDD) (Base 5 ºC, April 1-May 20, 2019) is below (Fig. 9):
The growing degree day map (GDD) (Base 10 ºC, April 1-May 15, 2019) is below (Fig. 10):
The lowest temperatures (°C) observed the past seven days range from -10 to 2 °C in the map below (Fig. 11).
The highest temperatures (°C) observed the past seven days range from -10 to 2 °C in the map below (Fig. 12).
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.
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 output indicates that alfalfa weevil hatch has begun and first instar alfalfa weevils should be present across most of AB (Fig. 1). Model runs for Brooks AB (Fig. 2) and Swift Current SK (Fig. 3) were projected to June 15, 2019. Second instar larvae will begin to occur late next week in fields near Brooks and 3-5 days later in the Swift Current region.
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.
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.
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.
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 (Oulema melanopus) – The CLB model was run for Lethbridge AB (Fig. 1), Brandon MB (Fig. 2), and 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 Lethbridge (Fig. 1) and Brandon (Fig. 2). Hatch is predicted to be 4-7 days later in the Peace River region (Fig. 3).
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.
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.
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”.
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 21, 2019, predicted grasshopper egg development was 66% (63% last week) and is similar to long term average values (68%) (Fig. 1).
Model runs for Grande Prairie (Fig. 3), Lethbridge (Fig. 4) and Saskatoon (Fig. 5) were projected to June 15, 2019. Results for Lethbridge (Fig. 4) and Saskatoon (Fig. 5) indicated that eggs should begin to hatch this week. Hatch in the Peace River region is predicted to be approximately one week later. Results also indicated that initial hatch (less than 6%) should have occurred in southwest SK and southeast AB.
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.
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 22, 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 reports are produced by:
The following crop reports are also available:
Public summer field events – Coming to a field near you – Our field crop entomologists are already scheduled to be at these 2019 field tour events from May-August (be sure to re-confirm dates and details as events are finalized):
• June 6, 2019. Farming Smarter crop walk or plot hop if you are a flea beetle! Access event information. Entomologist participating: Hector Carcamo
• June 20, 2019: Solstice Forage and Crops Field Tour to be held at the Beaverlodge Research Farm (Beaverlodge AB). View event info/registration details. Entomologists tentatively participating: Jennifer Otani, Keith Uloth
• June 26, 2019: 2019 CanolaPALOOZA to be held at the Lacombe Research and Development Centre (Lacombe AB). View event info/registration details. Entomologists tentatively participating: Jennifer Otani, Amanda Jorgensen, Meghan Vankosky, Scott Meers, Shelley Barkley, Patty Reid, Sunil Shivananjappa, Hector Carcamo, Julie Soroka, Mark Cutts, Jim Tansey, Sherrie Benson and the Junior Entomologists.
• July 9-12, July 16-18, 2019: Crop Diagnostic School. Held at the University of Manitoba Research Farm at Carman, Manitoba. An 2-week diagnostic school will complete units on entomology, plant pathology, weed science, soil fertility, pulse crop production, and oilseed production. View registration and event information. Entomologists participating: John Gavloski and Jordan Bannerman.
• July 9, 2019: CanolaPALOOZA Saskatoon, to be held at the SRDC Llewellyn Farm. Read more about this event. Entomologists presenting: Tyler Wist, James Tansey, Greg Sekulic, Meghan Vankosky
• July 23-24, 2019: Crop Diagnostic School, Scott Saskatchewan. Read more about this event. Entomologists presenting: Meghan Vankosky, Tyler Wist.
• July 24, 2019: Crops-a-Palooza. Held at Canada-Manitoba Crop Diversification Centre (CMCDC), Carberry, Manitoba. Read more about this event. Entomologist participating: John Gavloski, Vincent Hervet, Tharshi Nagalingam, Bryan Cassone.
• August 8, 2019: 2019 Wheatstalk to be held at Teepee Creek AB. View event info/registration details. Entomologists tentatively participating: Jennifer Otani, Amanda Jorgensen.
• August 8, 2019. Horticulture School. Agriculture and Agri-Food Canada Research Farm, Portage la Prairie, Manitoba. Entomologist presenting: John Gavloski, Kyle Bobiwash.
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
(This week’s post is provided by Dr. James Tansey, Saskatchewan Ministry of Agriculture, Provincial Specialist, Insect/Vertebrate Pest Management)
With the onset of the 2019 growing season, we decided to feature an insect that is becoming a growing problem throughout Canada: Spotted Wing Drosophila (SWD), Drosophila suzukii.
This invasive insect is thought to have originated in southeast Asia. The first record of SWD is from Japan in 1916. SWD is now established in small and stone fruit production areas throughout North America. SWD has been reported in British Columbia since 2009, and was first reported in Alberta in 2010. Although it has not yet been found in Saskatchewan, occurrence in Alberta and low levels in southern Manitoba suggest that SK infestations are likely imminent. Saskatchewan Ministry of Agriculture will be monitoring for this pest this summer (2019).
SWD is an economic pest of many soft fruits including raspberry, strawberry, cherry, blueberry and plum (Figure 1). Saskatoon berry has been documented as a host. Haskap is also considered susceptible but may escape major damage as SWD populations typically do not increase until after harvest. However, Ontario haskap growers have seen economic losses when a mild winter is coupled with factors that lead to delayed ripening.
SWD adults are 3-4 mm, yellow-brown with red eyes. Males have a conspicuous spot on the leading edge of each wing (Figure 2). Females lack the spots but have a characteristic large, serrated ovipositor (Figure 3).
SWD overwinter as adults. These become active in the spring, mate and seek egg-laying sites. Female SWD lay as many as 16 eggs per day for up to two months, averaging 384 eggs each. Female SWD deposit eggs with their serrated ovipositor under the skin of healthy, ripening fruit. Oviposition sites look like pin-holes in the skin (Figure 4). These can also serve as avenues of entry to pathogens like brown rot and botrytis. Several larvae can occur per fruit (Figure 5). Larval feeding causes fruit to become prematurely soft and unmarketable. Larvae mature in 3-13 days and pupate most commonly in the fruit. The pupal stage lasts another 3-15 days. Multiple generations per year are common.
Although SWD adults can be moved around by winds, movement of contaminated plant material is the major route for dispersal. Current management includes culling and destruction of soft fruit and the application of insecticides to established populations. Products registered to control SWD can be on Health Canada’s pesticide label search site (http://pr-rp.hc-sc.gc.ca/ls-re/index-eng.php). Use the search terms ‘spotted wing drosophila’. Product updates occur periodically so check this site regularly.
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.