Producers can help in the effort to find a wireworm control solution by submitting samples to Canada’s wireworm research team.
“Lindane (such as Vitavax Dual) insecticide kept wireworm numbers low for several decades on the Prairies,” says Neil Whatley, crop specialist with Alberta Agriculture and Rural Development.
“(But) since the ban of this organochlorine pesticide in 2004, wireworm damage in field crops is rebounding, (with) some researchers suggesting we may just be catching a glimpse of the tip of the iceberg at this point.”
There are about 30 different wireworm species, and they have diverse behaviours and life cycles, which makes a single control measure improbable. An individual region may contain more than one wireworm species.
The worm-like larvae can feed on plant roots and germinating seeds for up to five years before developing into the adult click beetle stage. While current seed treatments may repel wireworms for a growing season, their populations can continue to increase so that these treatment measures begin to fail.
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Canada’s wireworm research team, headed by Bob Vernon and Wim van Herk of Agriculture and Agri-Food Canada, is identifying wireworm species and researching 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,” says Whatley. “Although most crops are susceptible, wireworms prefer eating annual and perennial grasses, so populations can build up in fields that have extended periods of cereal crops or pasture. Crops grown in recently broken sod are especially vulnerable. Due to a greater amount of soil moisture, wireworms migrate near to the soil surface in early spring, making spring the best time to bait and capture wireworms.”
Baiting can be as simple as burying a small amount (a cup or so) of a cereal-based product such as flour, bran, or wheat seeds to a depth of four to six inches at marked locations randomly across a field. 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.
“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, and your name and phone number,” adds Whatley. “Once the species are identified, you will be contacted with the results.”
Samples should be mailed to Dr. Bob Vernon, Agriculture and Agri-Food Canada, 6947 No. 7 Hwy., P.O. Box 1000, Agassiz, B.C. V0M 1A0.