Previous Posts

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

Abundant parasitoids in canola – Week 10 
Alfalfa weevil – Week 6

Cabbage seedpod weevil – Week 12 
Cabbage root maggot – Week 11 
Cereal aphid manager (CAM) – Week 2
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

Monarch migration – Week 8

PMRA Pesticide Label Mobile App – Week 4

Scouting charts (canola and flax) – Week 3

Ticks and Lyme Disease – Week 4

Weather radar – Week 3
Wheat midge – Week 12

White grubs in fields – Week 8

Wind trajectories – Week 6
Wireworm distribution maps – Week 6

Previous Posts

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

Abundant parasitoids in canola – Week 10
Alfalfa weevil – Week 6

Cabbage seedpod weevil – Week 8 
Cabbage root maggot – Week 11 
Cereal aphid manager (CAM) – Week 2
Cereal leaf beetle – Week 5
Cereal leaf beetle larvae request – Week 8
Crop protection guides – Week 2
Crop reports – Week 8
Cutworms – Week 4

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

Field heroes – Week 8
Flea beetles – Week 4

Monarch migration – Week 8

Pea leaf weevil – Week 8
PMRA Pesticide Label Mobile App – Week 4

Scouting charts (canola and flax) – Week 3

Ticks and Lyme Disease – Week 4

Weather radar – Week 3
White grubs in fields – Week 8
Wind trajectories – Week 6
Wireworm distribution maps – Week 6

Previous Posts

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

Abundant parasitoids in canola – Week 10

Alfalfa weevil – Week 6

Cabbage seedpod weevil – Week 8 
Cereal aphid manager (CAM) – Week 2
Cereal leaf beetle – Week 5
Cereal leaf beetle larvae request – Week 8
Crop protection guides – Week 2
Crop reports – Week 8
Cutworms – Week 4

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

Field heroes – Week 8
Flea beetles – Week 4

Monarch migration – Week 8

Pea leaf weevil – Week 8
PMRA Pesticide Label Mobile App – Week 4

Scouting charts (canola and flax) – Week 3

Ticks and Lyme Disease – Week 4

Weather radar – Week 3
Wind trajectories – Week 6
Wireworm distribution maps – Week 6
White grubs in fields – Week 8

Previous Posts

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

Alfalfa weevil – Week 6

Cabbage seedpod weevil – Week 8 
Cereal aphid manager (CAM) – Week 2
Cereal leaf beetle – Week 5
Cereal leaf beetle larvae request – Week 8
Crop protection guides – Week 2
Crop reports – Week 8
Cutworms – Week 4

Diamondback moth – Week 7

Field heroes – Week 8
Flea beetles – Week 4

Monarch migration – Week 8

Pea leaf weevil – Week 8
PMRA Pesticide Label Mobile App – Week 4

Scouting charts (canola and flax) – Week 3

Ticks and Lyme Disease – Week 4

Weather radar – Week 3
West nile virus – Week 8
Wind trajectories – Week 6
Wireworm distribution maps – Week 6
White grubs in fields – Week 8

Wireworm distribution map

Reminder – Last week turned out to be our wireworm blitz!  This complicated group of insect species was featured in the Insect of the Week AND we include the survey results again this week!

The following maps summarize the main results of a survey of pest species of wireworms of the Canadian Prairie Provinces.  Samples (both larvae and beetles) were submitted to Dr. Bob Vernon’s lab in Agassiz, BC, from 2004 to 2017, and identified by Dr. Wim van Herk (Fig. 1).  Species identifications were confirmed with barcoding.

Figure 1.  Sampling locations for click beetles and wireworm larvae (Coleoptera: Elateridae) submitted for wireworm surveying from 2004-2017.

Approximately 600 samples were submitted, with the number of larvae per sample typically less than five (Fig. 1).  More samples are welcome, particularly from areas currently not well represented on the maps.  Please provide either the legal land description or latitude and longitude coordinates with a sample.  Any information on the cropping history or whether fields were irrigated is helpful.

Review the complete survey summary posted in Week 05 (for Jun 7, 2018).

Disclaimer: 
Please do not distribute or use the contents of this post, including any maps, without obtaining prior permission.

Obtain further information or arrange shipment of wireworm or click beetle samples by contacting:
Dr. Wim van Herk
Agriculture and Agri-Food Canada
Agassiz Research and Development Centre
6947 Highway 7, Agassiz, BC, V0M 1A0
wim.vanherk@agr.gc.ca

Insect of the Week – Wireworms

This week’s Insect of the Week is a frustrating pest of many crops: wireworm. Wireworms are the soil-dwelling larval stage of the click beetles (Elateridae). There are hundreds of click beetle species in the prairies, but the term wireworm refers to those that are pests, which in Canada is approximately 20 species. With the loss of effective insecticides (e.g. lindane), wireworms have re-emerged in recent years as primary pests of potato, cereals, and vegetables. On the prairies, we have 3 predominant pest species (Selatosomus destructor, Limonius californicus, and Hypnoidus bicolor; see photo), and their larvae vary (among other things) in life history (2-7 years), color (white to orange), cuticle thickness, distribution, behaviour, and susceptibility to insecticides.

Wireworms are patchy in distribution, difficult to monitor, and difficult to kill. We have a lot to learn about these resilient pests. Since the mid-1990’s AAFC has had a national research team (Bob Vernon et al.) screening for effective insecticides and developing trapping and monitoring methods, cultural controls (e.g., crop rotation), and biocontrols to manage the adult and larval forms of these pests.

For more information about wireworms, check out our Insect of the Week page!

The three most troublesome wireworm species on the prairies in their adult and larval stages. Note the different sizes and colours. From left to right, S. destructor, L. californicus, H. bicolor.
Photo by David Shack, AAFC-Lethbridge.

For more information, please contact Dr. Haley Catton (AAFC-Lethbridge) or Dr. Wim van Herk (AAFC-Agassiz)

Also link here to access a summary of Wireworm surveying (2004-2017) conducted across the Canadian prairies by van Herk and Vernon (AAFC-Agassiz).

Wireworm distribution map

The following maps summarize the main results of a survey of pest species of wireworms of the Canadian Prairie Provinces.  Samples (both larvae and beetles) were submitted to Dr. Bob Vernon’s lab in Agassiz, BC, from 2004 to 2017, and identified by Dr. Wim van Herk (Fig. 1).  Species identifications were confirmed with barcoding.

Figure 1.  Sampling locations for click beetles and wireworm larvae (Coleoptera: Elateridae) submitted for wireworm surveying from 2004-2017.

Approximately 600 samples were submitted, with the number of larvae per sample typically less than five (Fig. 1).  More samples are welcome, particularly from areas currently not well represented on the maps.  Please provide either the legal land description or latitude and longitude coordinates with a sample.  Any information on the cropping history or whether fields were irrigated is helpful.

The main findings of this survey are that:
1. Wireworms are re-emerging as primary pests of cereals and other crops, particularly in southern Alberta and Saskatchewan.  This can be attributed to several factors, including changes in seeding and cultivation resulting in higher soil moisture and increased food availability, and therefore greater wireworm survival; the elimination of effective insecticides such as lindane and the decline of organochlorine residues in the soil; and the present lack of insecticides that actually kill wireworms.

2. Limonius californicus is generally the predominant pest species in fields reporting heavy wireworm damage, occasionally building up to very high populations and resulting in complete crop wrecks (Fig. 2).  This was not the case when Glen et al. (1943) or Doane (1977) conducted their surveys; L. californicus was considered a minor species at those times.  Selatosomus destructor (Fig. 3) and Hypnoidus bicolor (Fig. 4) are still the most common species.  The pest status of another commonly found species, the predaceous Aeolus mellillus (Fig. 5), is unclear.  The following species listed by Glen et al. (1943) as pests of agriculture in the Prairie Provinces were found also, but infrequently: Agriotes mancusA. criddleiA. stabilisHemicrepidius memnoniusL. pectoralis, and various Dalopius sp.

Figure 2.  Distribution of Limonius californicus (Coleoptera: Elateridae) submitted for wireworm surveying from 2004-2017.
Figure 3.  Distribution of Selatosomus destructor (Coleoptera: Elateridae) submitted for wireworm surveying from 2004-2017.
Figure 4.  Distribution of Hypniodes bicolor (Coleoptera: Elateridae) submitted for wireworm surveying from 2004-2017.
Figure 5. Distribution of Aeolus mellillus (Coleoptera: Elateridae) submitted for wireworm surveying from 2004-2017.

3. Multiple pest species are frequently found in the same fields where damage is reported (i.e. about 25% of the time, despite the small number of larvae per sample).  This is particularly important as pest species can vary considerably in the type of damage they cause (e.g. it remains unclear if H. bicolor is damaging to potato), their life history (e.g. duration of the larval stage), and susceptibility to insecticides.

Details related to the biology and management of these species are reviewed in van Herk and Vernon (2014) and Vernon and van Herk (2013).

Acknowledgements:
These maps are only possible thanks to the collections done by a large team of local entomologists and agrologists.  We are extremely grateful to them; thank you to everyone who participated!  A special thank you to Ted Labun and colleagues at Syngenta Crop Protection (Canada), and to Bayer CropScience, for providing the bulk of the samples. 

Disclaimer: 
Please do not distribute or use the contents of this post, including any maps, without obtaining prior permission.

Obtain further information or arrange shipment of wireworm or click beetle samples by contacting:
Dr. Wim van Herk
Agriculture and Agri-Food Canada
Agassiz Research and Development Centre
6947 Highway 7, Agassiz, BC, V0M 1A0
wim.vanherk@agr.gc.ca

Further wireworm reading:
Burrage RH (1964) Trends in damage by wireworms (Coleoptera: Elateridae) in grain crops in Saskatchewan, 1954–1961. Canadian Journal of Plant Science, 44: 515–519.  https://doi.org/10.4141/cjps64-102 

Doane JF (1977) Spatial pattern and density of Ctenicera destructor and Hypolithus bicolor (Coleoptera: Elateridae) in soil in spring wheat. The Canadian Entomologist 109: 807–822. https://doi.org/10.4039/Ent109807-6

Doane JF (1977) The flat wireworm, Aeolus mellillus: studies on seasonal occurrence of adults and incidence of the larvae in the wireworm complex attacking wheat in Saskatchewan. Environmental Entomology 6: 818–822. https://doi.org/10.1093/ee/6.6.818 

Glen R, King KM, Arnason AP (1943) The identification of wireworms of economic importance in Canada. Canadian Journal of Research 21: 358-387. https://doi.org/10.1139/cjr43d-030

van Herk WG, Vernon RS (2014) Click beetles and wireworms (Coleoptera: Elateridae) of Alberta, Saskatchewan, and Manitoba.  In: Arthropods of Canadian Grasslands (Volume 4): Biodiversity and Systematics Part 2. (Edited by D.J. Giberson and H.A. Carcamo).  Biological Survey of Canada, pp. 87-117. https://biologicalsurvey.ca/monographs/read/17

Vernon RS, van Herk WG (2013) Wireworms as pests of potato. In: Insect pests of potato: Global perspectives on biology and management.  (Edited by P. Giordanengo, C. Vincent, A. Alyokhin).  Academic Press, Elsevier, Amsterdam, pp 103–164.  https://www.elsevier.com/books/insect-pests-of-potato/alyokhin/978-0-12-386895-4 

Zacharuk RY (1962) Distribution, habits, and development of Ctenicera destructor (Brown) in western Canada, with notes on the related species C. aeripennis (Kby.) (Coleoptera: Elateridae). Canadian Journal of Zoology 40: 539–552.  https://doi.org/10.1139/z62-046