Saskatoon, Saskatchewan
May 29, 2003

Using pheromones to control the orange wheat blossom midge could arm Prairie producers with a cheap and powerful defense against this destructive insect, say researchers at Simon Fraser University and Agriculture and Agri-Food Canada.

Each year growers spray millions of dollars of insecticides on their wheat crops to control wheat midge and endure up to $100 million in crop losses from this tiny orange fly. A new, three-year research project, supported in part by Western Grains Research Foundation's Endowment Fund, will examine the potential of pheromones to reduce these costs and provide more effective long-term control.

"While pheromone-based control will not completely eliminate the wheat midge, it could go a long way to reducing their numbers in Prairie fields, especially when used in combination with other control methods," says Dr. Gerhard Gries, who is conducting the research along with Dr. Owen Olfert at Agriculture and Agri-Food Canada. "This could mean considerable savings for wheat growers. Current insecticide applications can cost as much as $12 or $13 per acre. We think the cost of pheromone-based control could be cheaper than insecticides, but we won't know by how much until the research is completed."
 
The current situation, where growers rely mainly on one type of insecticide, can also lead to the development of insecticide-resistant midge populations, says Gries. Pheromones would reduce this risk, by providing a valuable alternative that is more compatible with other control options. "We continually have to develop new options for pest control that are cost-effective, compatible with other control methods and part of an effective long-term control strategy."

Pheromones are scents that insects emit to communicate with each other. Some serve as mating signals. The Simon Fraser University researchers previously identified the midge pheromone and will investigate its potential for midge control. The pheromone could be sprayed to confuse the insects and prevent them from mating.

"For the male midges, it's going to smell like there are females everywhere," says Gries. "But, because the males will never actually be able to pinpoint their locations, there will be no fertilized eggs."

The pheromone identified is the mating signal emitted by female midges, says Gries. "We will now attempt to demonstrate that it can be used to control midge populations, and work to determine the minimum dose needed for effective control. A commercial partner, 3M, has signed on to encapsulate the pheromone into a form that can be easily used by producers once the research is completed."

The project includes several steps. First researchers will divide fields into two sections. They will spray one section with microencapsulated pheromones and leave the other section untreated (control). They will also place one pheromone-baited trap per acre in both sections.

Following a treatment period, they will count the number of male midges captured in the traps and the number of midge maggots in all wheat heads from one plant near the traps. Next, they will assess the proportion of damaged and undamaged wheat kernels collected from all heads of one plant near each trap. No trap captures of midges in pheromone-sprayed sections would demonstrate successful disorientation of males. Most importantly, fewer maggots and lower damage in kernels of sprayed sections would demonstrate effective pheromone-based midge control.

The development of pheromone-based control for the wheat midge is likely to have a ripple effect on other pest control research, says Gries, with more researchers exploring the potential of pheromone-based pest control.

Endowment Fund support for the Gries project was supposed to begin in 2003, but that has been delayed one year because drought conditions have caused reductions in midge populations that will make it impossible to begin the research as scheduled. Endowment Fund has allocated over $17 million to more than 200 research projects since its inception in 1983. The Fund is administered by Western Grains Research Foundation.