Wireworm damage cost Price Edward Island potato growers around $6 million in 2014. Decades ago the click beetle larvae were successfully controlled with chlorinated hydrocarbon insecticides. Those agents were banned in the 1970s and 1980s because of their toxicity to animals and their tendency to build up in the soil.
Agriculture and Agri-Food Canada (AAFC) has developed a new “attract and kill” method to decimate wireworm populations and limit crop destruction. Dr. Bob Vernon, an AAFC research scientist, and his team at the Agassiz Research and Development Centre in British Columbia created the sustainable and cost-effective solution.
The “attract and kill” technique uses tiny amounts of insecticide and can be implemented at low cost with minor modifications to planting equipment. “With my method, you only need five grams of active ingredient per hectare. This new approach is superior not only in terms of reducing risks to the environment and to people, it also kills far more wireworms,” Vernon said.
Wheat seeds treated with an insecticide act as bait and are planted along with the potatoes. The wheat germinates first in the soil, after about 48 hours. During germination, the wheat produces carbon dioxide, which attracts the majority of the wireworms in the field to the planted potato rows. When they reach the wheat seed to feed, they contact the insecticide and die. This takes care of approximately 80-90 percent of the wireworm population in a field within about two weeks of planting, and protects the crop produced later in the summer.
The wheat is planted about 15 centimetres below the surface, which means there is little risk of contact with the vast majority of animal life in a field. Because so little insecticide is used, residue doesn’t build up in the soil.
Vernon told Farm Focus he’d worked on the method for “probably a decade.” In the first year “it worked extremely well and we have been refining it ever since to determine the minimum number of seeds needed to produce the desired effect, and to minimize the insecticide that has to be used.”
The researcher said the technique was tested in B.C. and Ontario. It worked on all wireworm species. “In Ontario my new method was effective in blemish (wireworm) control relative to the industry standard, Thimet.” The trials in British Columbia were even more effective. “Thimet reduces populations by 60 percent, the new method by 80-90 percent.”
“As new insecticides (and insecticide combinations) are developed they can be plugged into the system,” and should be available to growers in the not-too-distant future, Vernon said.