Purdue, Ohio State team up for marestail control
Purdue and Ohio State University Extensions teamed up to create a fact sheet to help farmers handle the obnoxious herbicide-resistant weed marestail, known to have effects on soybean yield and growth.
Marestail, also known as horseweed, grows in much of the Midwest, primarily emerging in late summer/fall and in late-March on through June. When allowed to grow, the weed competes with soybean plants for soil nutrients, space, water, and (when tall enough) sunlight.
There are tons of weeds out there, so what’s the big deal with marestail? Growing to between 3 and 6 feet tall, mature marestail doesn’t respond to one of the more commonly used herbicides, glyphosate. When a glyphosate-resistant weed like this is present, farmers need to pay particular attention to their application timing; they'll need to use a cocktail of other herbicides to achieve control.
Marestail is most vulnerable when it’s in the seedling or rosette stage, so Purdue/OSU specialists recommend applying burndown before the elongation, or bolting, period.
“Most populations of marestail in Ohio and Indiana are resistant to glyphosate, and will not be controlled by burndown or post-emergence applications of glyphosate alone,” said Mark Loux, Ohio State Extension weed scientist.
Loux and Purdue Extension weed scientist Bill Johnson created the fact sheet — which includes information about marestail biology, soybean yield loss, herbicide resistance, and steps for controlling and managing the weed — to aid in controlling marestail.
Source: Purdue Agriculture News