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Working towards better soybean cyst nematode manage
An early, dry spring means the return of soybean cyst nematode (SCN) symptoms for Ontario growers. And that’s a problem — the SCN, a small roundworm, attacks the roots of soybeans. It’s been quickly and drastically decreasing soybean yield in Ontario since it was detected here in 1988.
OMAFRA Field Crop Plant Pathologist Albert Tenuta and his collaborators are investigating the effectiveness of different nematicides at reducing yield loss in Ontario and the north central United States.
To measure SCN density, Tenuta and his team took soil samples from each of the 26 sites at planting and harvest for three years. They found treated soybean fields had better yields than untreated fields, but treatments that combined a nematicide, fungicide and insecticide showed the greatest yield.
This understanding contributes to the team’s goal, to develop soybean management practices that will help producers control SCN populations and minimize yield loss.
Funding for this research was provided by the Grain Farmers of Ontario through the Farm Innovation Program (a component of Growing Forward) and the North Central Soybean Research Program. •
Vary your weed management program to prevent glyphosate resistance
Years of reliance on glyphosate has resulted in certain biotypes of giant ragweed and Canada fleabane that are resistant to the herbicide.
For control, Profs. Peter Sikkema and Francois Tardif from the University of Guelph, working with Dr. Mark Lawton of Monsanto Canada, suggest producers introduce diversity in their weed management programs, including multiple herbicide modes of action and a diverse crop rotation.
The researchers found that Roundup® plus 2,4-D provided excellent control of giant ragweed. Roundup® plus Eragon™ provided excellent control of Canada fleabane.
Sikkema also suggests having a diverse crop rotation of up to three or four crops, including non-Roundup® Ready crops, to allow for the use of a variety of herbicides.
Additionally, some timely tillage can provide excellent control of weeds. “Since these weeds are very competitive, it is very important that farmers implement a diverse weed management system,” says Sikkema. “If these weeds aren’t controlled they can cause substantial yield losses.”
This project has been funded by Grain Farmers of Ontario, Monsanto and the Canadian Agricultural Adaptation Program.
The crop science industry is responding to the problem of glyphosate resistant weeds. Read more on page 36. •
Weed stress lowers corn and soybean yield
The effort required for corn and soybean plants to beat weeds can leave them weak, discoloured and more vulnerable to other environmental stressors, such as drought. Commercial crops don’t need that kind of competition.
To help them out, University of Guelph Plant Agriculture Prof. Clarence Swanton is leading a research initiative with Profs. Lewis Lukens and Elizabeth Lee to understand how crop plants such as corn or soybeans change their physiology in response to the presence of neighbouring weeds.
When plants compete with weeds, energy that would otherwise be used for growth in the plant’s roots is instead diverted to its stem to push itself above the invading weeds. However, this results in plants that have problems withstanding environmental or pest-related stress.
Swanton says that knowing how plants are behaving in response to weed competition will allow corn and soybean breeders to improve stress tolerance in these crops and reduce the amount of yield lost to stress.
“It’s vital to be aware of the damaging changes happening due to stress on corn and soybean plants so that farmers can preserve their yields,” says Swanton.
This research is funded in part by the Ontario Ministry of Agriculture, Food and Rural Affairs, the Natural Sciences and Engineering Research Council and Grain Farmers of Ontario. •
Research Roundup is provided by members of SPARK (Students Promoting Awareness of Research Knowledge) at the University of Guelph’s Office of Research. For more information, contact a SPARK writer at 519-824-4120, ext. 52667.