March 16, 2012

With the warmer temperatures this past week, alfalfa fields quickly moved out of dormancy and new shoots grew to several inches.

Spraying now with herbicides like Sencor, Velpar, Sinbar, or Karmex may injure these new green shoots. The injury may not be obvious, but it may delay plant growth a week or so.

Consider other herbicides, such as Pursuit or Raptor. They may cause a little injury, but they won’t delay growth as much as other products would.  Pursuit usually causes less injury than Raptor, but it doesn’t control downy brome.  Be sure to scout your alfalfa and select the herbicide best suited to the weeds you've identified.

If you are going to spray your alfalfa, do it soon. With warm temperatures, it won’t be long before these winter annual weeds start to bolt. Then it will be next to impossible for any herbicide to control them without doing serious damage to the crop.

Bruce Anderson
Extension Forage Specialist