Peak alfalfa weevil feeding damage occurs between 325 and 575 heat units (based on accumulation of heat units from January 1 with a base of 48°F). Locations in red are there, and locations in orange are getting close. Now is the time for most alfalfa growers to step up their alfalfa weevil scouting. For more details on alfalfa weevil scouting and thresholds please see our April 13 article https://agcrops.osu.edu/newsletter/corn-newsletter/2020-09/alfalfa-weevil-%E2%80%93-it%E2%80%99s-closer-you-think
Accumulated growing degree days (base 48°F sine calculation method) for January 1-May 3*, 2020 at several CFAES Ag Weather System (https://www.oardc.ohio-state.edu/weather1/) locations and additional NOAA stations around Ohio. *Ashtabula through April 30