Off-label glyphosate applications can be costly

Farmers are increasingly going “off label” applying higher rates of glyphosate to their Roundup Ready canola at a later crop stage than recommended, a survey commissioned by Monsanto Canada reveals.

As a result farmers are losing three bushels an acre, Monsanto Canada said in a recent new release citing its own research.

“The symptoms of injury are very subtle and not easy to diagnose so most farmers probably don’t even realize there is a significant financial impact because their crop doesn’t show any obvious signs of injury,” David Kelner, Monsanto Canada’s Winnipeg-based canola technical lead said.

“At today’s market value, losing three bushels per acre translates to a loss of roughly $40 per acre or more due to crop injury caused by spraying off label,” said Jesse Hamonic, Monsanto Canada’s canola trait marketing lead.

“Effective control of weeds is critical to producing a high-yielding crop so we understand that farmers want to do a good job of managing their weeds. But they may not fully appreciate how spraying too much, or spraying outside the application window, can have a detrimental impact on yield, and ultimately their bottom line.”

Adverse weather

When farmers spray too late it’s usually because they couldn’t spray earlier due to adverse weather, Gary Martens, an agronomy instructor at the University of Manitoba said in an interview April 12.

“Farmers would really like to spray at the three- to four-leaf stage,” he said. “I would think they are pretty well informed by now that that is the best time but unfortunately perhaps the field is too wet and they can’t get on it or it is too windy and then it gets behind. And then what do you do, not spray? No, because then your yield loss will be more than three bushels an acre. I think farmers are taking the best of two bad alternatives.”

Martens isn’t quite sure why farmers are upping rates, as they have been raised for the new Genuity Roundup Ready canola. Some weeds, such as wild buckwheat, are hard to control, he said.

“If you get it early and stick to maximum label rate you should be able to control wild buckwheat,” Martens said. “Farmers may be wanting to control some perennials. You could get some effect on Canada thistle and on dandelion. The thing I would go with instead of raising my rate is make sure I have good spray coverage and that I’m contacting all the weeds I’m trying to kill.”

An online survey of 1,700 farmers conducted last year by Stratus Agri-Marketing Inc. for Monsanto Canada shows 45 per cent of farmers sprayed above label rates, up eight percentage points from 2011.

The survey also found 30 per cent of farmers sprayed after the six-leaf stage, as well as spraying above label rates, up four percentage points from 2011 survey results.

Price drop

Retail prices for glyphosate have dropped significantly in recent years. While most farmers agree that’s a good thing, the price decrease makes it more affordable to spray higher rates of glyphosate on their Genuity Roundup Ready canola in an attempt to enhance weed control, Monsanto Canada’s release said.

The recommended label rate of a Roundup brand agricultural herbicide applied to Genuity Roundup Ready canola is either two applications of 0.33 litres an acre or one application of 0.5 litres an acre applied at the zero- to six-leaf stage.

Farmers encounter bad weather and tough-to-control weeds every year making spraying decisions difficult, Hamonic said. By sharing the survey results and Monsanto Canada’s field trial research, it’s hoped farmers will make better spraying decisions that put more dollars in their pockets, Monsanto Canada said.

“Effective control of weeds is critical to producing a high-yielding crop so we understand that farmers want to do a good job of managing their weeds,” Hamonic said. “But they may not fully appreciate how spraying too much, or spraying outside the application window, can have a detrimental impact on yield, and ultimately their bottom line.”

Monsanto Canada wants farmers to spray within label recommendations.

“It really is the best way to ensure an ideal growing experience with the Genuity Roundup Ready canola system,” he said.

About the author

Reporter

Allan Dawson

Allan Dawson is a reporter with the Manitoba Co-operator based near Miami, Man. Covering agriculture since 1980, Dawson has spent most of his career with the Co-operator except for several years with Farmers’ Independent Weekly and before that a Morden-Winkler area radio station.

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