Approaches to weed management in edible beans in Ontario

Project Summary

Ontario, is one the leading provinces in Canada in edible bean production, produces 129,000 MT of edible bean with a farm-gate value of approximately $90 million. Major market classes of edible bean grown in Ontario include black, cranberry, kidney, and white (navy) bean.

Edible bean is a short season crop with short physical stature and therefore is very sensitive to weed interference. Edible beans are more susceptible to yield losses due to weed interference than the other major field crops grown in Ontario. Edible bean seed yield has been reduced an average of 58% in research studies conducted in Ontario. This is greater than the other major field crops: corn (52%), soybean (40%), spring cereals (12%) and winter wheat (2%). In addition, presence of weeds in edible beans at the harvest time can also cause seed staining and interfere with harvesting efficiency.

More research is needed to develop innovative precision weed management strategies that have an adequate margin of crop safety, provide consistent broad spectrum weed control, have low environmental impact and maximize edible bean yield and net returns. Each year Ontario edible bean producers face a dilemma in respect to annual broadleaf weed control. Research has clearly demonstrated that the use of a broad spectrum soil applied herbicide program is the optimal approach to protect the crop during the critical period of weed control. The dilemma is, there is only one soil applied herbicide with predominantly broadleaf weed activity – imazethapyr. It is widely recognized that imazethapyr is a very efficacious soil applied broadleaf herbicide but it has a narrow margin of crop safety, especially in the small seeded market classes of edible beans, specifically white and black beans. White and black beans are two of the most widely grown market classes of edible beans in Ontario. Consequently, it is imperative that research be conducted to try to find alternatives to imazethapyr for broadleaf weed control. Preliminary research indicates that halosulfuron when used alone or in combination with other herbicides has the potential to provide acceptable control of troublesome annual broadleaf weeds with an acceptable margin of crop safety in edible beans.

This research program will develop innovative precision weed management strategies based on halosulfuron that are efficacious, environmentally acceptable and economically sustainable for edible bean production in Ontario. In addition, this project will address new weed management issues as they arise (including but not limited to) the effect of using UAN as the herbicide carrier for soil applied herbicides, the effect of soil nutrient level on herbicide injury and the interaction between soil borne diseases and herbicide injury.