Proper weed management is important for the success of winter crops after the fall harvest, a Purdue Extension weed specialist says.While the drought has led to a harvest earlier than normal, that also means farmers can prepare fields for winter crops, such as wheat, earlier this year.”Farmers looking to plant wheat in the next couple of weeks, as long as the crops are off the field, are in good shape. Now’s a good time to control weeds,” Bill Johnson said. Recent rain has helped weeds thrive, and farmers will need to do additional work to prepare their fields for their winter crops. “The drought has made weed management very difficult, but as for this fall, we actually have pretty good soil moisture right now, and weeds are growing, so the weeds are fairly sensitive to herbicides,” he said.
Two herbicides safe to use before planting wheat are glyphosate and gramaxone. Johnson recommends farmers avoid 2,4-D and dicamba herbicides in the fall because they can lead to poor stand establishment and wheat head sterility in the spring. Starting with a clean field is key to weed management for winter wheat and other crops. A field without overgrowth of weeds is important for stand establishment. “If there’s a dense infestation of weeds, you need to do something to control them, whether that’s herbicides or tillage,” Johnson said.
Weeds prevalent this fall include dandelions and winter annuals such as henbit, chickweed and purple deadnettle; grasses such as annual bluegrass and Carolina foxtail; and areas that were planted to annual rye cover crops and where the annual rye either was not killed during the summer or all of the seed did not germinate in the spring.
After planting wheat, farmers should scout their fields for weeds. Wheat needs to tiller well in the fall so there will be plenty of grain heads in the spring for production.
For more information about weeds affecting crops in Indiana and Ohio and a list of herbicides to help control them, visit www.extension.purdue.edu/extmedia/WS/WS-16-W.pdf