Insect of the Week – Biological control agents of weeds

Meghan Vankosky
Categories
Week 16

As we are nearing the end of the 2018 growing season, we decided to feature something a little bit different for this week’s Insect of the Week: insects that are biological control agents of weeds. Natural enemies of insects include parasitoids and predators that kill insect pests. Natural enemies of weeds include plant pathogens or insect herbivores that impact weed growth and reproduction, thus reducing reduce weed density. There are many insects that may be found in rangeland, forage and crop habitats that are biological control agents of weeds, some of which have been introduced purposely after rigorous testing for safety from places where our invasive plants have originated. Biological control agents of weeds act in two primary ways: plant herbivory and granivory. Plant herbivores consume root, leaves and./or shoots enough to typically reduce its ability to grow and reproduce, and thus its ability to compete with rangeland plants used in cattle grazing or with crops. Granivores or weed seed predators consume high numbers of weed seeds, thus reducing the number of viable weed seeds entering seed banks for germination in future growing seasons.

Ground beetles (Coleoptera: Carabidae) of several genera are known to eat weed seeds within crops, including Harpalus, Amara, Poecilus, and Pterostichus. The diets of some ground beetles almost entirely consist of weed seeds. Other ground beetles are primarily carnivores (i.e., generalist predators of other insects or slugs) that occasionally consume weed seeds. More information about the biology of ground beetles can be found by visiting the Insect of the Week page.

Mogulones crucifer (Pallas) is a biological control agent of hound’s-tongue (Cynoglossum officinale L.), a weedy pest of rangelands in southern British Columbia and southwestern Alberta. The adult stage of this weevil species (Coleoptera: Curculionidae) feeds on leaves of its host while the larvae consume the roots of the host plant. The weevil is highly mobile and has significantly reduced hound’s-tongue densities where it has been released for biological control. For more information about M. crucifer, visit https://www.for.gov.bc.ca/hra/plants/biocontrol/detailed_bioagent_pages/Mogulones_cruciger.htm

Prepared by Dr. Meghan Vankosky

Hound’s-tongue, an invasive species, is a host
plant for Mogulones crucifer
Photo: Jacob W. Frank
Mogulones crucifer adult on hound’s-tongue leaf
photo: Rosemarie De Clerk-Floate
Mogulones crucifer larvae infesting hound’s-tongue root
photo: Rosemarie De Clerk-Floate
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Weekly Update

Jennifer Otani, Ross Weiss, David Giffen, John Gavloski, Hector Carcamo, Meghan Vankosky, Erl Svendsen and Owen Olfert
Categories
Week 16

Greetings!

This is the last Weekly Update of the 2018 growing season. It is the 16th week of both the INSECT OF THE WEEK plus WEEKLY UPDATE – hopefully each has supported in-field scouting in our prairie field crops! 

Thank you to our many contributors and sincere appreciation is extended to the many people who repeatedly visited fields all season to support provincial AND prairie-wide insect pest monitoring in field crops in 2018!  

Access the complete Weekly Update either as a series of Posts for Week 16 (August 23, 2018) OR a downloadable PDF version.  Also review the “Insect of the Week” for Week 16!

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 three steps!

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Weather synopsis

Ross Weiss, David Giffen, Owen Olfert and Meghan Vankosky
Categories
Week 16

Weather synopsis – We close out the Weekly Update for the growing season by looking back at precipitation thanks to the AAFC Drought Watch folks.

This is a map of growing season precipitation (% of normal; Fig. 1):

Figure 1.  Percent of normal precipitation for the growing season (April 1-August 22, 2018) across the Canadian prairies. Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (23Aug2018).  Access the full map at http://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=true

The following map illustrates precipitation (% of normal) for the last 60 days (Fig. 2):

Figure 2. Percent of normal precipitation the past 60 days (as of August 22, 2018) across the Canadian prairies.
Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (23Aug2018).  Access the full map at http://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=true

Whereas this is the precipitation (% of normal) for the past 30 days (Fig. 3):

Figure 3. Percent of normal precipitation the past 30 days (as of August 22, 2018) across the Canadian prairies.
Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (23Aug2018).  Access the full map at http://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=true

Here is the accumulated precipitation the past 7 days (Fig. 4)!

Figure 4. Accumulated precipitation the past 7 days (as of August 22, 2018) across the Canadian prairies.
Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (23Aug2018).  Access the full map at http://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=true

The map below reflects the Highest Temperatures occurring over the past 7 days (August 16-22, 2018) across the prairies and is available from Agriculture and Agri-Food Canada (Fig. 5). 

Figure 5. Highest temperature across the Canadian prairies the past seven days (August 16-22, 2018). Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (23Aug2018).  Access the full map at http://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=true

 The map below reflects the Highest Temperatures occurring over the past 7 days (August 16-22, 2018) across the prairies and is available from Agriculture and Agri-Food Canada (Fig. 6). 

Figure 6. Lowest temperature across the Canadian prairies the past seven days (August 16-22, 2018). Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (23Aug2018).  Access the full map at http://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=true

Normally we share growing degree day maps calculated for the growing season including  March 1, 2018, to the present.  This week we instead reference the AAFC Drought Watch maps.  Below is the growing degree day map (GDD: Base 10ºC for APRIL 1 – August 20, 2018) and is available from Agriculture and Agri-Food Canada (Fig. 7):

Figure 7. Growing degree-day using base 10ºC for across the Canadian prairies for the growing season (APRIL 1-August 20, 2018). Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (23Aug2018).  Access the full map at http://www.agr.gc.ca/DW-GS/current-actuelles.jspx?lang=eng&jsEnabled=true

Below is the growing degree day map (GDD: Base 5ºC for APRIL 1 – August 20, 2018) and is available from Agriculture and Agri-Food Canada (Fig. 8):

Figure 8. Growing degree-day using base 5ºC for across the Canadian prairies for the growing season (APRIL 1-August 20, 2018). Image has not been reproduced in affiliation with, or with the endorsement of the Government of Canada and was retrieved (23Aug2018).  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 to continue to follow weather conditions during harvest and beyond.

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Pre-Harvest Intervals

Jennifer Otani
Categories
Week 16

Reminder – Pre-Harvest Interval (PHI) – Growers with late-season insect pest problems must factor in the PHI which is the minimum number of days between a pesticide application and swathing or straight combining of a crop.  

The PHI recommends sufficient time for a pesticide to break down and a PHI-value is both crop- and pesticide-specific.  Adhering to the PHI is important for a number of health-related reasons but also because Canada’s export customers strictly regulate and test for the presence of trace residues of pesticides.

An excellent summary of PHI for various pesticides in their various crops was posted by Saskatchewan Agriculture’s Danielle Stephens in 2016 within their Crop Production News.

In 2013, the Canola Council of Canada created and circulated their “Spray to Swath Interval Calculator” to help canola growers accurately estimate their PHI.  Other PHI are described in your provincial crop protection guides and remember that specific crop x pesticide combinations will mean different PHIs.  

Finally, work towards “Keeping It Clean” so your grain is ready for export!  More information about PHI and Maximum Residue Limits (MRL) is available on the Keeping It Clean site. 

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Slugs on wheat

Jennifer Otani
Categories
Week 16

Earlier this month, feeding channels on the upper surfaces of the flag leaf in wheat were reported and evening scouting revealed this 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.

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Plant bugs

Jennifer Otani
Categories
Week 16

Bugs of the Family Miridae are also referred to by their common name, “plant bugs”. Prairie growers are familiar with two plant bugs – lygus and alfalfa plant bugs.  

Plant bugs are a very large group of bugs that can include herbivores, omnivores and predators but virtually all are polyphagous which is a term referring to their ability to feed on several species, even Families of other organisms.  Plant bugs are generally very mobile as both adults and nymphs and move readily to feed on different host plants as the season progresses.  Plant bugs can also have different lifecycles with alfalfa plant bugs reproducing as one generation per year whereas lygus bugs can have two to three generations per year.

This season in southern Alberta, first-generation lygus bugs damaged seed alfalfa in June then the second generation damaged canola fields in July and August. High numbers of lygus bugs (10-20 per sweep and higher) were collected in research and demonstration plots of sainfoin, hemp and quinoa in southern Alberta.  

Both lygus and alfalfa plant bugs have sucking mouthparts and the larger, more mature nymphs plus adults are able to penetrate and extract oils from seeds, causing them to shrivel and lose in quality.  Plant bugs feeding in faba beans can cause spotting.

Wasps in the genus Peristenus include native species that attack lygus and alfalfa plant bugs but normally don’t occur in sufficient densities to reduce outbreaking populations of these plant bugs.  The exotic Peristenus digoneutis from Europe, if it could be established and is shown not to interfere with native predators and parasitoids, may increase parasitism to help prevent plant bug outbreaks.  

Adult L. lineolaris (5-6 mm long) (photo: AAFC-Saskatoon).
Fifth instar lygus bug nymph (3-4 mm long) (photo:  AAFC-Saskatoon).
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Harvest Sample Program

Jennifer Otani
Categories
Week 16

The Canadian Grain Commission is ready to grade grain samples harvested in 2018.  Samples are accepted up to November but send samples 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 where growers can register online to receive a kit to submit their grain.  

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

  • dockage assessment on canola
  • unofficial grade
  • 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 soybean
  • NEW for 2018-19: Participants will receive Falling Number and deoxynivalenol (DON) results for their wheat samples at no cost. This enhancement to the Harvest Sample Program is the first initiative to be funded by the Canadian Grain Commission’s accumulated surplus.

Many producers find having both grade and quality information on their samples before delivering their grain to be helpful.

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Provincial Insect Pest Reports

James Tansey, John Gavloski and Scott Meers
Categories
Week 16

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 2018 can be accessed here. Issue #13 (posted August 22, 2018).

Saskatchewan‘s Crop Production News for 2018 is posted with Issue #7 now available. This issue includes an update from the Crop Protection Lab.

Alberta Agriculture and Forestry’s Call of the Land regularly includes insect pest updates from Scott Meers. The most recent Call of the Land was posted August 23, 2018.

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Previous Posts

Jennifer Otani
Categories
Week 16

The following is a list of 2018 Posts – click to review:

Abundant parasitoids in canola – Week 10 
Alfalfa weevil – Week 6
Aphid App – Week 12

Bertha armyworm – Week 15

Cabbage seedpod weevil – Week 12 
Cabbage root maggot – Week 11 
Cereal aphid manager (CAM) – Week 2
Cereal leaf beetle – Week 13
Cereal leaf beetle larvae request – Week 8
Crop protection guides – Week 2
Cutworms – Week 4

Diamondback moth – Week 7
Download the field guide – Week 10

Field heroes – Week 8
Flea beetles – Week 4
Flea beetles – Week 15

Grasshopper simulation model output – Week 13

Ladybird beetles – Week 15
Lygus in canola – Week 15

Monarch migration – Week 8

Pea leaf weevil – Week 13

PMRA Pesticide Label Mobile App – Week 4

Scouting charts (canola and flax) – Week 3

Thrips – Week 15
Ticks and Lyme Disease – Week 4

Weather radar – Week 3
West nile virus risk – Week 13
Wheat midge – Week 12

White grubs in fields – Week 8

Wind trajectories – Week 6

Wireworm distribution maps – Week 6

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Review the 2018 INSECT OF THE WEEK!

Jennifer Otani
Categories
Week 16

Need a refresher or simply want to keep our 2018 lineup a click away? Here’s the 2018 INSECT OF THE WEEK lineup for the growing season:

Wk01 (May 07, 2018) – Glassy cutworm
Wk02 (May 14, 2018) – Darksided cutworm
Wk03 (21 May, 2018) – Ground beetles: cutworm natural enemies
Wk04 (May 28, 2018) – Flea Beetles
Wk05 (June 4, 2018) – Wireworms
Wk06 (June 11, 2018) – Pterostichus melanarius
Wk07 (June 18, 2018) – Red turnip beetle
Wk08 (June 25, 2018) – Bruner grasshopper
Wk09 (July 03, 2018) – Pea aphid (Hemiptera: Aphididae) 
Wk10 (July 09, 2018) – Natural enemies of pea aphids
Wk11 (July 16, 2018) – The new canola flower midge
Wk12 (July 23, 2018) – Natural enemies of the canola flower midge
Wk13 (July 30, 2018) – Wheat stem sawfly (Cephus cinctus, Hymenoptera: Cephidae)
Wk14 (Aug 07, 2018) – Natural Enemies of the wheat stem sawfly
Extra (Aug 10, 2018) – English grain aphid (Hemiptera: Aphididae)
Wk 15 (Aug 13, 2018) – Twospotted spider mite (Acarina: Tetranychus)
Wk16 (August 20, 2018) – Biological control agents of weeds

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Review the WEEKLY UPDATE for 2018 growing season!

Jennifer Otani
Categories
Week 16

Access the WEEKLY UPDATE as either a series of Posts OR downloadable PDF file for the entire 2018 growing season: 

Wk01 – May 10, 2018
Wk02 – May 17, 2018
Wk03 – May 24, 2018
Wk04 – May 31, 2018
Wk05 – Jun 07, 2018
Wk06 – Jun 14, 2018
Wk07 – Jun 21, 2018
Wk08 – Jun 28, 2018
Wk09 – Jul 05, 2018
Wk10 – Jul 12, 2018
Wk11 – Jul 19, 2018
Wk12 – Jul 26, 2018
Wk13 – Aug 02, 2018
Wk14 – Aug 09, 2018
Wk15 – Aug 16, 2018
Wk16 – Aug 23, 2018

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Upcoming Meetings and Conferences

Jennifer Otani
Categories
Week 16

Upcoming Meetings and Conferences – The following agricultural insect pest-related meetings and conferences will be held – be sure to re-confirm dates and details as events are finalized:

  • September 27-29, 2018:  The Entomological Society of Alberta Annual Meeting will be held at Edmonton AB and information is available here.
  • October 18, 2018:  The Western Committee on Crop Pests will meet at Lloydminster SK and information is available here.  
  • October 23-25, 2018:  The 11th Canadian Pulse Research Workshop will be held at Edmonton.  More information is available here.  
  • October 23-25, 2018:  The 2018 Canola Discovery Forum will be held at Banff AB.  More information is available here.  
  • November 11-14, 2018:  The Joint Annual Meeting of the Entomological Society of Canada, Entomological Society of America and Entomological Society of British Columbia meets at Vancouver BCand information is available here. 
  • January 15-16, 2019:  CropSphere Agricultural Conference will be held at TCU Place in Saskatoon SK during Crop Production Week.  More information is available at: https://www.cropsphere.com/index.cfm 
  • January 22-24, 2019: The Manitoba Ag Days show will be held at the Keystone Centre in Brandon MB. More information will be available at: https://www.agdays.com/show-info/
  • January 29-31, 2019:  FarmTech 2019 will be held in Edmonton AB and information is available at http://farmtechconference.com/  with registration typically opening early in November.

Please send other IPM-related conference and meetings to jennifer.otani@agr.gc.ca to update this information.

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