Treat perennial weeds in early fall to take advantage of winter weather, recommends Bob Klein, University of Nebraska crops specialist in North Platte.

"One reason for spraying weeds around Sept. 1 is that the herbicide weakens them and the winter can finish them off," he adds. "When crop producers spray in spring, the weeds have ideal growing conditions to recover."

Weeds that are growing actively in early fall, take nutrients down to the roots. They also carry the herbicide to the root. In fact, to do a really good job of eliminating perennial weeds, producers should make sure the weeds are actively growing and are not under moisture stress.

Producers might want to delay treatment if fall weather gets dry and the weeds are not growing.  Although it's not likely in 2009, sometimes fall is so dry that producers can't successfully treat, Klein says. In that case, it's probably better to make a spring application. Hopefully, the following fall will provide better growing conditions.

Always be sure to apply the correct herbicides for the weeds you have, Klein advises. To help select herbicides, check the 2009 Nebraska Guide for Weed Management available online at www.ianrpubs.unl.edu/epublic/live/ec130/build/ec130.pdf.