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Agronomic Crops Network

Ohio State University Extension

CFAES

Reminder to Scout for Alfalfa Weevil

Despite the colder start to the year, we are still accumulating growing degree days (GDD). The southern portion of the state is in the prime range, of between 325 and 575 GDDs, for alfalfa weevil feeding and damage. For the northern part of the state, don’t let the lower GDDs give you a false sense of security. Despite lower GDDs, alfalfa weevils may be present. Identifying a problem early gives you a greater opportunity for control, in what always seems to be a hectic spring.Figure 1. Map of accumulated growing degree days (base 48°F sine calculation method) for January 1 – April 21, 2025 at CFAES Ag Weather stations across the state (https://weather.cfaes.osu.edu//) and additional NOAA stations around Ohio (Midwestern Regional Climate Center (https://www.mrcc.purdue.edu))

To brush up on your alfalfa weevil scouting procedure, an article was written earlier this year outlining how to scout for alfalfa weevil and can be found here: Alfalfa Weevil Scouting and GDD. There is also a great video resource outlining the process here: Alfalfa Weevil Scouting Video.

Crop Observation and Recommendation Network

C.O.R.N. Newsletter is a summary of crop observations, related information, and appropriate recommendations for Ohio crop producers and industry. C.O.R.N. Newsletter is produced by the Ohio State University Extension Agronomy Team, state specialists at The Ohio State University and the Ohio Agricultural Research and Development Center (OARDC). C.O.R.N. Newsletter questions are directed to Extension and OARDC state specialists and associates at Ohio State.