If you've been out scouting your alfalfa fields, you may have noticed some alfalfa weevil damage.The weevil’s growth is based on growing degree days (GDD).
If you have yet to get out and scout your fields, do so as soon as possible. Spraying when damage can be seen from the road is just revenge, not good management.
This link to the following article tells what to look for and how to control/manage alfalfa weevils.