The confirmation of glyphosate resistant weeds in southern Manitoba did not come as a surprise, says the provincial weed specialist.
However, the location of Manitoba's first two cases of glyphosate resistant kochia populations - the Red River Valley - was unexpected, says Nasir Shaik.
"We were expecting glyphosate resistant kochia to show up on the western side of the province where we have way more kochia plants," he says.
The provincial ag department's confirmation this week of resistant plants is a major concern for farmers as glyphosate is the active ingredient in an important herbicide used to kill many weeds - the herbicide commonly known as "Roundup."
It's unknown whether the plants migrated from the US on floodwaters, or whether resistance developed after repeated glyphosate applications on the affected fields, notes Shaik. GR kochia has already been found in North Dakota, Minnesota, Saskatchewan and Alberta.
He says with more farms using minimum or zero-till practices, the risk of resistance developing remains higher on fields in western Manitoba.
"We have a lot larger population of kochia on the western side of the province and a lot more farms using zero-till systems, where glyphosate is a key herbicide," says Shaik. "
The two cases in the Red River Valley were found through a survey of 283 kochia populations across the province last fall. One of the positive results came from a field that was used to grow Roundup Ready soybeans in 2013, and the other grew Roundup Ready corn.
Shaik strongly urges farmers across the province to take measures to prevent the spread of glyphosate resistance.
"To begin they should be very watchful of the number of applications of glyphosate in a season. The second important recommendation would be to use a more complex application of herbicides, such as tank-mixing two or three," he explains. "Farmers should also try some non-herbicidal measures of weed control, such as tillage or manual weeding. One of the growers is doing manual weeding in the field to control the weed."
Manitoba Agriculture, Food and Rural Development will be developing programs to educate growers about herbicide-tolerance through the spring and summer, adds Shaik.
Source: SteinbachOnline