Wheat farmers are poised to get a leg up in the battle with bugs as research supported by Western Grains Research Foundation (WGRF) delivers new wheat varieties with stronger genetic resistance to several of the most costly insects.

The new varieties will help farmers protect their wheat crop from fluctuating insect populations, says Dr. Ron Knox, a researcher at Agriculture and Agri-Food Canada (AAFC) in Swift Current. As a control option, genetic resistance or "built-in" protection carries advantages for keeping costs low and minimizing environmental impact.

A leading example is research toward genetic resistance to the orange blossom wheat midge. Several variety development programs that have very good resistance in a number of experimental lines that have strong potential to become commercial varieties in the next couple years. The focus now is on improving the package of traits in varieties that have this resistance, and on adding further sources of resistance to provide more effective and longer lasting control.

Wheat midge typically reduces the Western Canada's wheat harvest by 10 percent, and in peak years by up to 30 percent. Insecticides are available that provide effective control, but they add cost for producers. The resistant varieties emerging should dramatically reduce the reliance on insecticides to control wheat midge, says Knox.

"When you consider the cost of spraying and the tight margins producers operate under today, that shift in control approach can go a long way to helping producers farm profitably."

Researchers have also gained ground against the wheat stem sawfly. In the past five years, the sawfly has re-emerged with great force, particularly throughout the Palliser Triangle of southern Alberta and southwestern Saskatchewan. Farmers in the sawfly risk area have typically experienced 30 to 50 percent sawfly-toppled wheat, with some fields reaching 90 percent damage.

To protect wheat from this insect, researchers have developed varieties with a greater degree of stem solidness. This approach is based on knowledge that the female sawfly inserts its eggs into hollow wheat stems. As a result, varieties with greater solidness results in crushed eggs, less mobile larvae, overwintering difficulty and lower fertility rate for surviving populations.

The latest variety is Lillian, which can reduce sawfly damage by 50 to 75 percent. "AC Lillian is representative of the new sawfly-resistant lines under development, which feature stem solidness with a better overall agronomic and quality package," says Dr. Ron DePauw, wheat breeder at AAFC Swift Current.

Another key area is Hessian fly resistance. "The Hessian fly is a sporadic pest of spring wheat throughout all wheat growing areas of Western Canada," explains Dr. Gavin Humphreys of AAFC Winnipeg. "Various resistant genes have been bred into winter wheat cultivars in the United States but none of these genes have been added to spring wheats grown in Canada." Last year, Humphreys and colleagues screened advanced breeding lines for resistance. "We found several lines with a good level of Hessian fly resistance," he says.

Wheat scientists have also made gains against the wheat curl mite, which carries Wheat Streak Mosaic Virus (WSMV). The virus is a major disease concern in winter wheat growing areas, where the virus can cycle between the spring and winter crops creating ideal conditions for epidemics. The team at AAFC Lethbridge has registered a new winter wheat variety called Radiant, available for the first time in 2005, which is the first Canadian variety with WSMV resistance.

"When the wheat curl mite feeds on susceptible lines, the leaves curl to create an 'onion-leaf' type tube, which provides an ideal, protected environment for the mite to reproduce," says Dr. Rob Graf, wheat breeder at AAFC Lethbridge. "Resistant lines do not exhibit this leaf curling response."

More information on genetic progress toward insect resistance is available in the August edition of Western Grains Research Magazine, now available on the WGRF Web site at www.westerngrains.com.

Western Canadian wheat and barley growers are major investors in breeding research through the Wheat and Barley Check-off Funds, administered by WGRF. The Research Magazine offers "Ideas and issues for farmer research investors."