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Wireworms – We’re Just Seeing the Tip of the Iceberg (PCN Spring 2016) MAR 29 2016 | Consumers and Producers | Pulse Crop News

This article appeared in the Spring 2016 issue of Pulse Crop News.

Neil Whatley, Alberta Agriculture & Forestry

As damage to field crops is poised to escalate, consider proactively finding a wireworm control solution for your area by submitting samples to Canada’s wireworm research team.

Lindane (e.g. Vitavax Dual, etc.) insecticide kept wireworm numbers low for several decades on the Prairies. Since the ban of this organochlorine pesticide in 2004, wireworm damage in field crops is rebounding. Some researchers say we’re just seeing the tip of the iceberg.

Varying from region to region, some 30 different wireworm species exhibit diverse behaviours and lifecycles, making a single control measure improbable. An individual region may contain more than one wireworm species. Depending on the species, the worm-like larvae can feed on plant roots and germinating seeds for up to three to five years before developing into the adult click beetle stage. While current seed treatments may repel wireworms for a growing season, their populations continue to increase so that these treatment measures begin to fail.

Due to their preference to eat annual or perennial grasses, wireworm populations can build up in fields that have extended periods of cereal crops or pasture. Pulses, oilseeds, potatoes and sugar beets are susceptible to wireworm damage when grown in rotation with cereals. Crops grown in recently broken sod are especially vulnerable. Non-farmed areas like grassy ditches and undisturbed field borders also harbour wireworms and click beetles.

Canada’s wireworm research team, headed by Dr. Robert Vernon and Dr. Wim van Herk of Agriculture and Agri-Food Canada, is identifying wireworm species and researching new control measures. The research team needs to know which specific wireworm species dominates in your farming region so the correct control option(s) can be applied as the problem worsens.

Due to a greater amount of soil moisture, wireworms migrate near to the soil surface in early spring when soil temperatures rise above 5˚C, making spring the best time to bait and capture wireworms.

Baiting can be as simple as burying a cup of a cereal-based product like flour, bran or wheat seeds to a depth of four to six inches into the soil at marked locations. Dig up the baits 10 to 14 days later, collecting wireworms and some field soil (not too wet), and then insert them into a hard plastic container for shipping. There may be more than one species present, so collect as many wireworms as possible.

Mail your wireworm sample to:

Dr. Robert Vernon
Agriculture and Agri-Food Canada
6947 #7 Hwy, P.O. Box 1000
Agassiz, B.C. V0M 1AO

Include a brief description of where the sample was collected (nearest town or address), information about your crop rotation in this field over the past four years, your name and telephone number. Once the species is identified, you will be contacted with the results.