Archives

New research project tackles sawfly on several research fronts

It's been called "a ghost from the past" for wheat growers. Now, a team of Prairie researchers plans to send the wheat stem sawfly back where it came from.

A new research project supported in part by farmers through Western Grains Research Foundation is taking a multi-faceted approach to helping farmers defend against the sawfly, which has risen the past several years to become the most damaging insect pest of wheat in Western Canada.

"The sawfly is an old problem our researchers have battled for much of the century," says Dr. Ron DePauw, wheat breeder and head of cereal research at Agriculture and Agri-Food Canada's (AAFC) Semiarid Prairie Agricultural Research Centre (SPARC) in Swift Current. "In recent years, we've seen a new cycle of sawfly infestation that has resulted in major losses for producers, who haven't had much in the way of control options. The new project will address this challenge, by exploring potential solutions on several fronts and bringing them together for effective, integrated pest management strategies."

Along with DePauw, the project includes quantitative geneticist Dr. Fran Clarke, molecular geneticist / pathologist Dr. Ron Knox and durum breeder Dr. John Clarke of AAFC Swift Current; agronomist Brian Beres, entomologist Dr. Hector Carcamo, wheat breeder Dr. Rob Graf and agrometeorologist Dr. Sean McGinn of AAFC Lethbridge; and cytogeneticist Dr. Taing Aung of AAFC Winnipeg.

The multi-disciplinary team covers all the major components needed for strategies to reduce sawfly damage over the long-term, says DePauw. While the main focus is on developing new sawfly-resistant wheat varieties, learning the nature of this genetic resistance, along with understanding sawfly behavior and population dynamics is essential to the effort.

"The common end point is to control damage by the wheat stem sawfly," says DePauw. "Developing varieties with improved sawfly resistance will go a long way to helping farmers, but there will not be any one silver bullet. From a breeding perspective, we're aiming for steady improvements in resistance over the long-term, and incorporating new sources of resistance to avoid the breakdown of any one source. Agronomic strategies and other aspects of the effort are essential to minimize the risk and extend the lifespan of our resistance sources.

"For example, an understanding of the biology of the wheat stem sawfly and parasitoids that feed on them may lead to agronomic practices that contribute to control of the wheat stem sawfly."

Over the past five years, wheat stem sawfly infestation and damage to wheat crops has increased dramatically, particularly throughout the Palliser Triangle of southern Alberta and southwestern Saskatchewan. The sawfly cannot be controlled by pesticide application and there are limited control options aside from shifting rotations away from wheat and other at-risk cereal crops. Producers growing susceptible crops in this area have typically experienced sawfly damage in 30 to 50 percent of their crops, with some fields reaching above 70 percent damage.

To this point, researchers have concentrated mainly on developing solid-stemmed wheat varieties, says DePauw. Female sawfly insert their eggs into the hollow stem of the wheat plant, and the damage is caused by the larvae that develops inside the stem. Wheat with higher stem solidness can prevent the sawfly from inserting eggs and can reduce the chance of larval survival. A key product of this effort is AC Abbey, a semi-solid stemmed hard red spring wheat variety. While AC Abbey is not immune, it has enough resistance to reduce sawfly damage by over 50 percent compared to hollow-stemmed wheat.

Wheat breeders are working on several potential successors with higher sawfly resistance and an improved quality package, which will emerge over the next several years. As part of the new project, they will also work toward sawfly-resistant winter wheat varieties.

The overall sawfly resistance breeding effort has been supported by the WGRF Wheat Check-off Fund. The new integrated sawfly control project is based largely on government funds matched to the farmer dollars through AAFC's Matching Investment Initiative.

The project is also supported by a portion of the royalties received and reinvested by WGRF. As part of its funding agreements with breeding institutions, the Foundation receives a share of the royalties generated by Check-off funded varieties. WGRF's producer Board has decided to funnel these royalties - over $360,000 since 1998 - back into specific projects in the breeding programs that developed the varieties.

The Wheat Check-off Fund, administered by Western Grains Research Foundation, allocates over $4 million annually to wheat breeding programs in Western Canada.

© 2003 Meristem Information Resources Ltd.
Meristem® is a registered trademark of Meristem Information Resources Ltd. All rights reserved.
Legal Disclaimer