With flashlights in hand, farmers wade into wheat fields at sunset hunting for signs of orange wheat blossom midge.
Now pheromone traps designed to attract the pests can handle the once painstaking task and make precise calculations that measure the degree of midge problems.
Owen Olfert, research scientist at Agriculture Canada in Saskatoon, said trials have shown the trap’s value.
“It’s an early warning system,” said Olfert.
He said a sticky lure allows farmers to count midge numbers, with 10 adults caught over a few days representing a significant problem. Midge lay their eggs in wheat heads and typically fly after sunset.
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Olfert cited an increased incidence of wheat midge in Saskatchewan and Manitoba, with the pests also moving into Alberta.
Larval damage within the head varies from underdeveloped and deformed kernels to aborted kernels, resulting in lowered yields and grade. The impact of the wheat midge can be huge, decimating almost an entire field. Damage from wheat midge was pegged at more than $150 million on the Prairies in 1995.
Pheromone traps, tailored to specific insects, are in place for pests like bertha armyworms and diamondback moths. Others are in the works for flea beetles in canola.
For wheat blossom midge, green cardboard triangular traps are moun-ted on wooden posts in fields at wheat head height. Three traps are recommended for each quarter section. Each trap and lure costs about $8.
“An investment of $20 on a quarter section of land with wheat is probably not a bad investment,” Olfert said.
Researchers at Simon Fraser University in British Columbia identified the female sex pheromone of the wheat midge. Working with Agriculture Canada and Phero-Tech Inc., they developed a species-specific monitoring system.
Wheat midge males are attracted to the pheromone inside the traps and are visible as orange spots on the sticky white inserts. Each orange spot is assumed to be a wheat midge because few other types of midge are found in wheat crops.
Researchers found a significant correlation between the number of captured males and the percentage of damage at harvest.
Those numbers could help growers more accurately pinpoint midge numbers and target spraying.
Alberta Agriculture entomologist Mike Dolinski said these traps will be a useful tool.
“We think this will be a real boon to farmers to make better decisions on what their risk is and when they should apply their treatment,” he said.
The traps are available from Phero-Tech through its western Canadian distributor Agri-Trend at order@agritrend.com.
Ervin Kovacs, Phero-Tech’s agricultural sales representative, advised setting the traps in low-lying areas because wheat midge thrive in moist soils. The use of rubber gloves is advised to avoid getting human scent on the traps.
Kovacs said accurate monitoring is important because there is only a five-day window for wheat midge control.
“If you spray too late, the larvae will bore into the developing kernel and that’s too late,” said Kovacs.
