August 4, 2010

August plantings of alfalfa work well, especially when there’s sufficient moisture. This year, however, grasshoppers may present a frustrating and potentially costly challenge for growers.  To avoid grasshopper problems and protect your investment:

1. Scout for grasshoppers. If you find more than two or three grasshoppers per square yard in the field to be planted or more than 10 grasshoppers per square yard in field margins, insecticide treatments probably will help.
    
2. Treat field margins before new alfalfa seedlings begin to emerge to head off potential invasions. See the Department of Entomology website for treatment thresholds and labeled insecticides for grasshoppers in alfalfa.

With any insecticide, be especially careful to avoid injuring bees and other important pollinating insects. To protect bees spray during the day when bees are less active, use less toxic insecticides, and avoid areas with blooming plants.

Bruce Anderson
Extension Forage Specialist