Crop Scene Investigation - 22 Solved: Whats the culprit in Bill's sprayer tank?
Tuesday, February 16, 2010
by BERNARD TOBIN
Bill was correct in believing that corn, a monocot crop, can tolerate an application of most cereal herbicides. Unfortunately, corn can't withstand cereal herbicides that control grassy weeds.
In this case, Bill's Roundup Ready corn suffered serious injury after being sprayed with Achieve Liquid, a grass herbicide. Only 20 to 30 litres of Achieve Liquid and Buctril-M remained in the tank when Bill topped it up with water and glyphosate to spray his corn. But it was enough to cause considerable damage to Bill's cornfield, explains Mike Cowbrough, the Ontario Ministry of Agriculture, Food and Rural Affairs Weed Management Lead.
Achieve Liquid is one those unique products that has some pretty amazing selectivity. That's why it can control wild oats in a wheat crop, but it is sensitive to corn, says Cowbrough.
After diagnosing the problem with Bill's cornfield, the University of Guelph conducted an experiment where they duplicated Bill's spray tank mixture at Elora Research Station to prove Cowbrough's theory. It certainly killed a lot of volunteer corn at the research station, he says.
Cowbrough estimates that the majority of Ontario's wheat crop is sprayed with a broad-leaf herbicide such as Buctril-M. You hardly ever use grass herbicides in a wheat crop unless it's spring cereal with annual grass pressure or you have a wild oat problem.
The best advice is to always check the label before applying any herbicide. The Achieve Liquid label does not recommend that the product be applied in corn. Cleaning out the sprayer before changing herbicides is another management practice to avoid herbicide injury. Congratulations to Doug Pettman Underhill Farm Supplies Vienna, Ont. for his correct answer. "I custom spray in Bayham Township and some days I don't have the same thing in two times." Underhill notes. "You pull the end caps and flush. That is the only way to have peace of mind," he concludes. BF