Alfalfa Weevil Predictor Map for June 2

Alfalfa Weevil Predictor Map for June 2

June 6, 2008

Growers in the northern half of Nebraska should be carefully checking fields for injury and presence of alfalfa weevils. Accumulated growing degree days (GDD), using a base of 48°F, can be used to help predict alfalfa weevil activity. Egg hatch begins at 300 degree days accumulated since January 1. Maximum damage will occur from about 450 to 600 GDDs. The May 9 CropWatch discussed scouting procedures, economic thresholds and control options for alfalfa weevil. (Maps developed by Al Dutcher, State Meteorologist, High Plains Climate Center).

Nebraska map showing degree day accumulation since Jan. 1 to forecast alfalfa weevil development. Southern counties should be scouting.

Figure 1. Accumulated growing degrees base 48° from Jan. 1 through June 1. (Map developed by Al Dutcher, State Meteorologist, High Plains Climate Center).