Weekly Update

Jennifer Otani, Ross Weiss, David Giffen, Serge Trudel, Sandra Younie, Erl Svendsen, Owen Olfert and Meghan Vankosky
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Week 19

Greetings!

Week 19 for 2019!  Please access the complete Weekly Update either as a series of Posts for Week 19 (August 15, 2019) OR a downloadable PDF. Be sure to check out the Insect of the Week – this growing season features doppelgangers to aid in-field scouting!

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!

Weather synopsis

Ross Weiss, David Giffen, Sandra Younie, Owen Olfert and Meghan Vankosky
Categories
Week 19

This past week (August 6-12, 2019) prairie temperatures were almost 3 °C cooler than last week (Fig. 1). The warmest temperatures were observed in southern AB and MB and eastern AB. 

Figure 1. Average temperature (°C) across the Canadian prairies the past seven days (August 6-12, 2019).

Across the prairies, 30 day (July 13- August 12, 2019; Fig. 2) average temperatures were slightly cooler than long term climate normals (Fig. 3). Temperatures were warmest across MB.

Figure 2. Average temperature (°C) across the Canadian prairies the past 30 days (July 13-August 12, 2019).
Figure 3. Mean temperature difference (°C) from Normal observed across the Canadian prairies for the past month (July 16-August 12 2019).  
Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (15Aug2019).  Access the full map at http://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=true

Growing season temperatures (April 1-August 12, 2019) continue to be approximately 1 °C cooler than average (Fig. 4).

Figure 4. Average temperature (°C) across the Canadian prairies for the growing season (April 1-August 12, 2019).

Significant rainfall amounts were reported across parts of the northern Peace River region, southern AB and SK (Fig. 5). Across the prairies, rainfall amounts for the past 30 days have been lowest across the southern prairies (Fig. 6). 

Figure 5. Cumulative precipitation observed the past seven days across the Canadian prairies (August 6-12, 2019).
Figure 6. Cumulative precipitation observed the past 30 days across the Canadian prairies (July 13-August 12, 2019).

Growing season rainfall amounts (Fig. 7) have been below average across southern regions of AB and west-central SK (Fig. 8). 

Figure 7. Cumulative precipitation observed across the Canadian prairies for the growing season (April 1-August 12, 2019) .
Figure 8. Percent of average precipitation observed across the Canadian prairies for the growing season (April 1-August 14, 2019).  
Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (15Aug2019).  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 5 ºC, April 1-August 11, 2019) is below (Fig. 9):

The growing degree day map (GDD) (Base 10 ºC, April 1-August 11, 2019) is below (Fig. 10):

The lowest temperatures (°C) observed the past seven days ranged from at least 12 down to below 0 °C in the map below (Fig. 11).

Figure 11. Lowest temperatures (°C) observed across the Canadian prairies the past seven days (to August 14, 2019).  
Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (15Aug2019).  Access the full map at http://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=true

The highest temperatures (°C) observed the past seven days ranged from at least 20 up to at least 32 °C in the map below (Fig. 12).

Figure 12. Highest temperatures (°C) observed across the Canadian prairies the past seven days (to August 14, 2019).  
Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (15Aug2019).  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 can bookmark the AAFC Drought Watch Maps for the growing season.

Predicted grasshopper development

Ross Weiss, David Giffen, Owen Olfert and Meghan Vankosky
Categories
Week 19

Grasshopper Simulation Model Output – 
Grasshopper development is progressing and populations are primarily in the adult stage (Fig. 1). Based on model runs, approximately 65% of the population should be in the adult stage (50% last week). Grasshopper development continues to be slower than average development. Based on climate data, 80% of the population would be expected to be in adult stage. Model output indicates that oviposition has begun in southern areas prairies (Fig. 2).

Figure 1. Predicted percent of grasshopper (Melanoplus sanguinipes) populations attaining adult stage across the Canadian prairies (as of August 14, 2019). 
Figure 2. Predicted overview of where oviposition has started (as of August 12, 2019).

The Insect of the Week’s Doppelganger featured GRASSHOPPERS for Week 14!!  Check out the excellent nymph photos to help your in-field scouting!

Biological and monitoring information related to grasshoppers in field crops is posted by Manitoba AgricultureSaskatchewan AgricultureAlberta 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” which is available as a free downloadable document in either an English-enhanced or French-enhanced version.

Bertha armyworm monitoring

Jennifer Otani
Categories
Week 19

Bertha armyworm (Lepidoptera: Mamestra configurata– Important – Watch for updates from your provincial monitoring networks who are compiling cumulative pheromone-baited trap interceptions to assess risk levels in AlbertaSaskatchewan (updated 07Aug2019), and Manitoba (locate table on pg 6).  Regions in all three prairie provinces are reporting “uncertain” risk based on pheromone-baited unitrap cumulative counts.  

SCOUT NOW to confirm in-field larval counts and REMEMBER that LARVAL DENSITIES CAN VARY DRAMATICALLY even between adjacent fields!  Scout to protect @FieldHeroes and avoid economic losses! Use the Field Heroes’ scouting guide for bertha armyworm and be sure to read more at their website!

Biological and monitoring information related to bertha armyworm in field crops is posted by the provinces of ManitobaSaskatchewanAlberta and the Prairie Pest Monitoring Network. Also refer to the bertha armyworm pages within the “Field Crop and Forage Pests and their Natural Enemies in Western Canada: Identification and management field guide” which is a free downloadable document as both an English-enhanced or French-enhanced version.


Refer to the PPMN Bertha armyworm monitoring protocol for help when performing in-field scouting.  Use the images below (Fig. 1) to help identify egg masses and the economically important larvae in canola.


Figure 1. Stages of bertha armyworm from egg (A), larva (B), pupa (C) to adult (D).
Photos: J. Williams (Agriculture and Agri-Food Canada).


Now is the time to do in-field scouting for this insect pest.  Review the Insect of the Week which features bertha armyworm and its doppelganger, the clover cutworm!

Wanted – Slugs in field crops

Jennifer Otani
Categories
Week 19

This year, wet field conditions contributed to slug issues in cereals and canola.  Researchers based at the University of Alberta are seeking live slug samples from field crops.  Please take note of their collection protocol and help, if possible please!

Reminder –  Feeding channels on the upper surfaces of the flag leaf in wheat were reported and evening scouting revealed the culprit!

Figure 1. Deroceras reticulatum, the “grey field slug”, on wheat growing near Crooked Creek AB (August 2, 2018; det. Lien Luong).
Figure 2.  Flag leaf feeding damage  on wheat caused by the grey field slug (Deroceras reticulatum).
Photo taken near Crooked Creek AB on August 2, 2018, by J. Otani.

Field scouting was performed in the evening from 8:30-10:30pm.  As the temperatures decreased, the slugs moved up the wheat stems, climbing to the topside of the flag leaf and onto the wheat heads although they did not appear to feed at the developing kernels. Wheat was hand-collected by clipping stems ~20cm above the ground to later reveal a density of 1.04 slugs per stem (n=465 stems) causing the above damage (Fig. 2). 

Specimens were forwarded to L. Luong (U of A) who identified the slugs from the above field as one species, Deroceras reticulatum, the grey field slug.  The majority were juveniles. The grey field slug is the most common to occur in the home garden.

Thanks to Dr. John Gavloski (Manitoba Agriculture) who prepared the following in relation to slugs in field crops:

  • Slugs are a complicated problem because most general insecticides don’t work well on them.  
  • Sluggo Professional (PCP#30025) is registered for slugs in field crops. It is a bait, which must be consumed by the slugs to be effective but it could be expensive on a large field.  
  • Often insecticides don’t work well on slugs and it may be related to the mucous coating slugs exude.  
  • Be wary, if an insecticide is applied, the product will likely not affect the slugs but it will kill the ground beetles and other natural enemies that prey upon or parasitize slugs and could exacerbate the slug problem.  
  • Growers using no-till or minimum till operations may consider tillage to help reduce future levels of slugs.  

Health Canada has an overview of snails relating to gardening posted here.

West Nile Virus and Culex tarsalis

David Giffen, Owen Olfert and Meghan Vankosky
Categories
Week 19

West Nile Virus Risk –  Health Canada posts information related to West Nile Virus in Canada.  Health Canada also tracks West Nile Virus through humanmosquitobird and horse surveillance.  Link here to access the most current weekly update (August 3, 2019). The screenshot below was retrieved 15Aug2019 as reference but access that information here.

The following is offered to predict when Culex tarsalis will begin to fly across the Canadian prairies (Fig. 1). Protect yourself by wearing DEET!  This week, regions most advanced in degree-day accumulations for Culex tarsalis, the vector for West Nile Virus, are shown in the map below.  As of August 11, 2019, areas highlighted orange are on the verge of approaching sufficient heat accumulation for mosquitoes to emerge.  Areas highlighted red in the map below should now have C. tarsalis in flight.

Figure 1. Predicted development of Culex tarsalis, across the Canadian prairies (as of August 11, 2019).

Once adults emerge, the following map demonstrates how quickly a Culex tarsalis mosquito carrying WNV can become fully infective (i.e., when it has accumulated 109 base 14.3° degree days) – it’s a matter of days, depending on the region (Figure 2).  For example, as of August 11, 2019, Foremost AB was predicted to only take 16-18 days for C. tarsalis to become fully infective.

Harvest Sample Program

Jennifer Otani
Categories
Week 19

The Canadian Grain Commission is ready to grade grain samples harvested in 2019.  Register online to receive a harvest sample kit (by October 15, 2019).  Samples are accepted until the end of November but send as soon a harvest is complete.

This is a FREE opportunity for growers to gain unofficial insight into the quality of their grain and to obtain valuable dockage information and details associated with damage or quality issues.  The data collected also helps Canada market its grain to the world!

More information on the Harvest Sample Program is available at the Canadian Grain Commission’s website.

In exchange for your samples, the CGC assesses and provides the following unofficial results FOR FREE:

  • Unofficial grade*
  • Dockage assessment on canola
  • Protein content on barley, beans, chick peas, lentils, oats, peas and wheat
  • Oil, protein and chlorophyll content for canola
  • Oil and protein content and iodine value for flaxseed
  • Oil and protein for mustard seed and soybeans
  • Falling number for wheat
  • Vomitoxin (deoxynivalenol or DON) levels for wheat and corn

Many producers find having both grade and quality information on their samples before delivering their grain to be helpful.  Sign up for a harvest sample kit before October 15, 2019.

Provincial Insect Pest Reports

James Tansey, John Gavloski and Scott Meers
Categories
Week 19

Provincial entomologists provide insect pest updates throughout the growing season so we link to their most recent information: 

Manitoba’s Crop Pest Updates for 2019 are posted here. Access Issue #13 posted August 13, 2019, noting continued grasshopper concern, the presence of new generation flea beetle adults in canola, and a repeated call for grasshopper surveyors.

Reminder – Saskatchewan’s Crops Blog Posts includes a segment on “Economic thresholds” by Kaeley Kindrachuk posted in May 2019. Also access the Crop Production News with Issue #6 (featuring pesticide drift information).

•  Reminder – Alberta Agriculture and Forestry’s Agri-News includes an insect-related item in the July 8, 2019 edition with an important reminder that field scouting in July can lead to a more successful crop.

Crop report links

Jennifer Otani
Categories
Week 19

Crop reports are produced by:

The following crop reports are also available:

Previous Posts

Jennifer Otani
Categories
Week 19

Click to review these earlier 2019 Posts:

2019 Risk and forecast maps – Week 2

Alfalfa weevil – Week 11

Bertha armyworm (predicted development) – Week 12

Cabbage seedpod weevil – Week 11
Cereal aphid manager APP – Week 12
Cereal leaf beetle – Week 9
Crop protection guides – Week 6
Cutworms – Week 5

Diamondback moth – Week 15

Field events – Week 10
Field heroes – Week 6
Flea beetles – Week 5

Grasshoppers – Week 10

Insect scouting chart for Canola – Week 5
Insect scouting chart for Flax – Week 5

Lygus in canola – Week 18

Monarch migration – Week 13

Painted lady butterfly – Week 8
Pea leaf weevil – Week 10
Prairie Crop Disease Monitoring Network – Week 11
Preparing grains for market – Week 15

Ticks and Lyme disease – Week 4
Timely IOTW to review – Week 13

Weather Radar – Week 6
Wheat midge – Week 17
Wildfires – Week 8

Wind trajectories – Review Page for list of PDFs for Weeks 1-12

Doppelgangers: Hoverflies vs. bees vs. yellow jacket wasps

Meghan Vankosky
Categories
Week 19

Hoverflies are un-BEE-lievably good mimics of bees and yellow jacket wasps!

Mimicry is used by insects in several ways.
Some insects, like the ambush bug and praying mantis, look like plants. These predators sit very still, blending into their surroundings, and wait very patiently for their unwitting prey to pass by. Other insects, use mimicry to avoid predation, often by taking on the appearance of species with clear markings that are known to be dangerous. Hoverflies (Diptera: Syrphidae) are some of the most convincing mimics of all of the insects. Even experts can have a difficult time distinguishing hoverflies from bees and wasps, especially when working in the field.

Bees (honeybees, solitary bees, native bees; Hymenoptera: Apidae): Bees are important pollinators, usually with distinctive black and yellow strips. Bees have two pairs of wings and are much fuzzier than wasps or hoverflies. Bees have stingers, but are not aggressive under normal circumstances. Some species of bees (e.g. honeybees) have barbed stingers that become lodged inside their victim. When this happens, the stinger is pulled out of the body of the bee and the bee dies. For this reason, bees with barbed stingers only sting as a last resort, in an effort to protect their colony. Bees are beneficial insects that will leave you alone if you leave them alone.

Honeybee
cc-by 2.0 Renee Grayson

Yellow jacket wasps (Hymenoptera: Vespidae): Yellow jackets and some of their close relatives have colouring similar to bees. Like bees, wasps have two pairs of wings. Unlike bees, which are usually vegetarians, wasps are carnivores that eat other insects. Thus, wasps are beneficial insects, but they also have a bad reputation for harming people because they scavenge for food at our picnics and barbecues during the summer. Wasps also tend to be aggressive and will sting with little provocation.

Yellow jacket wasp
cc-by-nc-nd 2.0 Bryan Jones

Hoverflies (Diptera: Syrphidae): Hoverflies belong to a completely different order of insects than bees and wasps. Like bees, hoverflies are pollinators and are often observed hovering over flowering plants in fields and gardens. Unlike bees and wasps, hoverflies only have one pair of wings. Hoverflies do not have a stinger. They also do not have biting mouthparts, so they can do no harm to people. Hoverflies protect themselves from predators, and people, by mimicking bees and wasps. In addition to pollinating plants, hoverflies provide another important ecosystem service: their larvae are predators of small plant-dwelling insects like aphids!

Syrphid fly
cc-by-nc-sa 2.0 Eero Sarkkinen

The case of the innocuous versus the evil twin: When making pest management decisions, be sure that the suspect is actually a pest. This can be challenge since insects often mimic each other or look very similar. An insect that looks, moves and acts like a pest may in fact be a look-alike or doppelganger.

Doppelgangers may be related (e.g. same genus) or may not be related, as in the case of monarch butterflies (Danaus plexippus) and viceroys (Limenitis achrippus).  Doppelgangers are usually relatively harmless but sometimes the doppelganger is a pest yet their behaviour, lifecycle or hosts may be different.

Correctly identifying a pest enables selection of the most accurate scouting or monitoring protocol. Identification and monitoring enables the application of economic thresholds. It also enables a producer to select and apply the most effective control option(s) including method and timing of application.  For the rest of the growing season, the Insect of the Week will feature insect crop pests and their doppelgangers.

Review previously featured insects by visiting the Insect of the Week page.

Contributed by Dr. Meghan Vankosky (@vanbugsky). 


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