Consider top tips for fall herbicide applications from several weed experts
Willis Smith’s No. 1 tip is to use a herbicide or combination of herbicides that targets the weeds you’re after. The Certified Crops Adviser with Senesacs also suggests using a mix with burndown capability. You still want residual activity to carry you as far into spring as possible. Beware, however, that you may then be committed to a specific crop.
Smith’s third tip is to delay application until soil temperatures drop well below 50 degrees F to slow breakdown of the herbicides. Fourth, use manufacturer’s recommended rates, or be ready to be disappointed next spring. Finally, don’t apply herbicides on frozen ground.
Steve Gauck, with Beck’s Hybrids, also a CCA, has a different outlook. He recommends spraying early in the fall right after harvest, using a quart of 2,4-D to control marestail and using glyphosate to get weeds already up and growing.
He says to pick good growing conditions. Spray weeds when they’re 1 to 3 inches tall.
The Purdue weed control crew of Johnson, Nice, Jordan and Bauman offer their own tips in the 2010 Weed Guide online. “For control of winter annual weeds, apply herbicide any time after early October,” it reads. For dandelions, however, delay application until after a frost.
“We’ve applied as early as late December for control of winter annuals, but we generally recommend application when dandelions are mostly green, or by mid-November.” they say.
This article published in the September, 2010 edition of INDIANA PRAIRIE FARMER.