By Kyle Verhoff and Emma Matcham et.al
Alfalfa weevils are active, so now is the time to get out and scout our fields. With above average growing degree days (GDD) across the state in March, alfalfa weevils are growing in their size and their ability to cause damage. Alfalfa weevil are one of the two main insect pests for alfalfa in Ohio and do a majority of their damage feeding on alfalfa foliage before first cutting. Alfalfa weevil adults and some eggs overwinter in Ohio fields, and when temperatures exceed 48°F, they begin to feed and develop. Knowing that they develop as GDDs accumulate, we can monitor the temperature and scout when they are likely to be most active. Peak activity and feeding damage take place between 325 and 575 GDD (accumulation from a base of starting at 48°F January 1st). With average March temperatures soaring to 6-11 °F above normal, much of southern Ohio is already above that 325 GDD mark ranging from 352 to 526. Northern Ohio is not far behind with . . .
Source : osu.edu