Ross Weiss, Owen Olfert, David Giffen and Erl Svendsen
Across the prairies, meteorological conditions were similar to long term average values for the period of May 30 – June 5, 2016. The average temperature was 12.8 °C and was 1.5 °C warmer than the previous week.
This week’s rainfall was generally greater than long term average amounts. Since April 1, most regions have reported above normal precipitation. Southeastern Saskatchewan and southern Manitoba reported the highest rainfall amounts. The map below shows the Accumulated Precipitation the past 7 days (i.e., May 30-June 5, 2016):
Soil moisture levels (refer to model output map) were predicted to be above average across most of the prairies.
For the period of May 1-31, 2016, conditions were cooler and wetter in Alberta than Saskatchewan and Manitoba.
The map below reflects the Accumulated Precipitation for the Growing Season so far for the prairie provinces (i.e., April 1-May 30, 2016):
Compared to last week, overnight temperatures were warmer the past 7 days. The map below shows the Lowest Temperatures the Past 7 Days (June 1-7, 2016) across the prairies:
The map below shows the Highest Temperatures the Past 7 Days (June 1-7, 2016):
The updated growing degree day map (GDD) (Base 5ºC, March 1 – June 5, 2016) is below:
While the growing degree day map (GDD) (Base 10ºC, March 1 – June 5, 2015) is below:
The maps above are all produced by Agriculture and Agri-Food Canada. Growers may wish to bookmark the AAFC Drought Watch Maps for the growing season.
Diamondback moth (Plutellidae: Plutella xylostella) – Once the diamondback moth is present in the area, it is important to monitor individual canola fields for larvae. 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. 2) dislodged from the plant. Repeat this procedure at least in five locations in the field to get an accurate count.
Figure 2. Diamondback larva measuring ~8mm long.
Note brown head capsule and forked appearance of prolegs on posterior.
Figure 3. 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).
Reminder – Pheromone traps attracting male Diamondback moths (Fig. 1) have been deployed across the prairies.
Figure 1. Diamondback moth.
Across the prairies, provincial staff coordinate diamondback pheromone trapping during the growing season: ● Counts will be reported by the provincial staff in Saskatchewan. ● Manitoba Agriculture and Rural Initiatives posted low DBM counts which can be reviewed within their second Insect Report. ● Alberta Agriculture and Forestry has a live 2016 map reporting Diamondback moth pheromone trap interceptions. A copy of the map (retrieved June 8, 2016) is below for reference.
Cutworms (Noctuidae) – The past week, cutworms were reported across Manitoba, Saskatchewan and Alberta.
Keep an eye on 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. Several species of cutworms can be present in fields. 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 and Rural Initiatives cutworm fact sheet which includes action and economic thresholds for cutworms in several crops.
More information about cutworms can be found by accessing the pages from the new “Field Crop and Forage Pests and their Natural Enemies in Western Canada: Identification and Field Guide”. View an excerpt of ONLY the Cutworm pagesfrom the new “Field Crop and Forage Pests and their Natural Enemies in Western Canada: Identification and management field guide”. The guide is available as a free downloadable document as both an English-enhanced or French-enhanced version.
For Manitobans….The earlier Insect Update included great photos of dingy and redbacked cutworms plus monitoring tips including how to discern these two species from one another. Reports of cutworm continued in the most recent Insect Update.
For Saskatchewanians…. Cutworms were reported in the recent Saskatchewan Insect Report. For Albertans….. Additional reports of cutworms have occurred throughout the province the past week! If you find cutworms, please consider using the Alberta Pest Surveillance Network’s “2016 Cutworm Reporting Tool”. Once data entry occurs, your growers can view the live 2016 cutworm map.
A screen shot of the live map has been retrieved (06Jun2016) below for your reference.
Julie Soroka, Jennifer Otani, Ross Weiss, Owen Olfert and David Giffen
Alfalfa Weevil (Hypera postica) – 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). Updated – Degree-day maps of base 9°C are now being produced by Soroka, Olfert, and Giffen (2016) using the Harcourt/North Dakota models. The aim or the modelling is to predict the development of Alfalfa weevil (Hypera postica) across the prairies and to help growers time their in-field scouting as second-instar larvae are predicted to occur. Compare the following predicted development stages and degree-day values copied below (Soroka 2015) to the map below.
For the week of June 5, 2016, second instar larvae are predicted to be present in fields falling within areas of the map highlighted ANY shade of purple. Third and fourth instar larvae are predicted to be present in fields falling within areas highlighted ANY shade of blue in the map below. Scout field and compare larval densities to the action threshold for alfalfa weevil which varies according to end use and crop stage.
Ross Weiss, Owen Olfert, David Giffen and prairiepest_admin
Grasshoppers (Acrididae) –Warm temperatures in Saskatchewan and southern Manitoba were predicted to result in enhanced development.
The model predicted that 41% of the hatch is complete(versus 23% last week).
Approximately 25% of the population was predicted to be in the first instar whereas 11% were predicted to be in the second instar. Development is well ahead of average rates (9% hatch, 7% first instar and 2% second instar).
Weekly surveying conducted by AAFC-Saskatoon Staff on June 2, 2016, confirmed that Melanoplines were primarily first and second instar stages although a few third instar nymphs were collected.
The following image showing various stages of the clearwinged grasshopper is provided below – note that adults have wings extending the length of the abdomen whereas nymphs lack wings but develop wing buds that will eventually mature to wings.
Bertha armyworm (Lepidoptera: Mamestra configurata) – Bertha armyworm (BAW) pupal
development is progressing well owing to the recent warmer weather. Moths
should have appeared in pheromone traps theweek
of June 5, 2016!
Those monitoring BAW pheromone traps may want to compare trap “catches” to the following reference photo kindly shared by Saskatchewan Agriculture below:
Provincial staff coordinate BAW pheromone trapping across the prairies and summarize cumulative counts in report or map formats:
John Gavloski, Scott Meers, Scott Hartley and prairiepest_admin
Provincial entomologists provide insect pest updates throughout the growing season so we have attempted to link to their most recent information: – Manitoba’s Insect and Disease Update (June 3, 2016, prepared by John Gavloski and Pratisara Bajracharya). – Saskatchewan’s Insect Report (Issue 2, prepared by Scott Hartley). – Watch for Alberta Agriculture and Forestry’s Call of the Land for updates from Scott Meers who recently gave a summary (posted on June 2, 2016).
Questions or problems accessing the contents of this Weekly Update? Please e-mail either Dr. Owen Olfert or Jennifer Otani. Past “Weekly Updates” are very kindly archived to the Western Forum website by webmaster, Dr. Kelly Turkington.
Ross Weiss, Owen Olfert, Serge Trudel and prairiepest_admin
Wind trajectory data processing by AAFC-Saskatoon Staff began in April. Reverse Trajectories track arriving air masses back to their point of origin while Forward Trajectories predict favourable winds expected to arrive across the Canadian Prairies. THE WEEK OF June 6, 2016: Nothing to report this week!
Ross Weiss, Owen Olfert, Serge Trudel and prairiepest_admin
Wind trajectory data processing by AAFC-Saskatoon Staff began in April. Reverse Trajectories track arriving air masses back to their point of origin while Forward Trajectories predict favourable winds expected to arrive across the Canadian Prairies.
THE WEEK OF June 6, 2016: Nothing to report this week!
Blister Beetles (predator) Last year, the focus of the Insect of the Week was crop pests. This year, we’re changing things up and highlighting the many natural enemies that help you out, silently and efficiently killing off crop pests. [note: featured Insects of the Week in 2015 are available on the Insect of the Week page] This week’s Insect of the Week is the blister beetle (Lytta nuttalli and Epicauta spp.). This is a good news/bad news story. The good news is that the Epicauta spp. larvae feed on grasshopper eggs. But the bad news is that the Nuttall blister beetle larvae feed on ground-dwelling leaf-cutter and bumble bees. The bad news continues: adult blister beetles contain a toxin, cantharidin. When beetles get baled in with alfalfa hay, the toxin can cause severe distress in livestock, especially horses.
See more information in the new Field Crop and Forage Pests and their Natural Enemies in Western Canada – Identification and Management Field Guide for identification, life cycle and conservation options (download links for field guide available on the Insect of the Week page).