Herbicide resistance is becoming a big concern among Manitoba farmers.

Dr. Rob Gulden, of the University of Manitoba, discussed the issue last week at St. Jean Farm Days. He says a recent survey has shown that the majority of fields in the province are showing some kind of herbicide resistant weed, with new types of weeds showing herbicide resistant characteristics.

Gulden explained why resistance to glyphosate is becoming a major issue in soybeans.

"Glyphosate resistant weeds in soybeans are a real concern in that soybeans are not a very competitive crop, unfortunately, and so they require a lot of in-crop herbicide use to keep them weed free," he said. "Unfortunately those multiple in-crop applications then lead to the selection for glyphosate resistant weeds."

He notes to help get a handle on the situation, it's important for farmers to use multiple modes of action when applying herbicide in their crops. It's also critical to make the crop more competitive by using higher seeding rates and narrow row spacing.