To be honest, I’m not sure if we will have wide spread alfalfa weevil damage in 2008. However, each year it seems that someone in the states does. Last year we saw a noticeable increase in weevil incidence and severity compared to previous years. That by itself doesn’t mean weevil damage will be higher this year. But it does give us a reminder that we should continue to scout alfalfa fields in a timely manner. The accumulation of 300 weevil degree days (base 48 degrees) is normally considered the time to start weevil scouting and that event will start very soon in the southern part of the state. 

There are several sources of degree day information including The Wisconsin Pest Bulletin (http://pestbulletin.wi.gov/ ) and the WI MN Cooperative Extension Weather website (http://www.soils.wisc.edu/wimnext/ ) which can be used to help schedule this event.   If time permits, spot-checking sandy knolls and/or south facing slopes (areas which warm up quicker) prior to 300 weevil degree days can give you a “heads-up” on weevil activity in your area.  Look closely at the terminal leaves for small pin-hole feeding and for larvae. Early instar larvae are commonly found in folded leaflets at the terminal portion of the stem and may not have the typical lime green coloration. Instead they may be a pale yellow color but will have a black head and a white stripe on their backs.