Reduce Spring Pressure; Manage Winter Annuals this Fall - UNL CropWatch, Oct. 21, 2011

Reduce Spring Pressure; Manage Winter Annuals this Fall - UNL CropWatch, Oct. 21, 2011

October 21, 2011

This has been a good fall for alfalfa, as well as for winter annuals like pennycress, mustards, henbit, and downy brome that are trying to get a start in your alfalfa.

If you walk through your field, you are apt to find small henbit plants, mustard rosettes, or short grass seedlings of downy brome. The density and robust start of what we’re seeing this fall suggest heavy weed growth next spring. If left uncontrolled, they could grow rapidly, reducing alfalfa yield, thinning stands, and lowering forage quality.

To avoid this, spray fields this fall before soils freeze up. Several herbicides are available, including Sencor, Sinbar, and Velpar, which will do an an excellent job of controlling pennycress, mustards, and downy brome. Raptor would be a good choice for henbit.

Waiting until spring to treat weeds can work, but it may be risky. Sring spraying of alfalfa must be done before alfalfa greens up or the alfalfa could be injured. Usually, there are only a few days in spring when alfalfa is dormant, weeds are actively growing, and it’s not too wet or windy. Most of the time, fields don’t get sprayed at all or they get sprayed late and alfalfa suffers some setback.

Manage that risk by taking opportunities now to control weeds in your alfalfa.

Bruce Anderson
Extension Forage Specialist