The adult female of the seed chalcid (length about one-eighth of an inch) has a needle-like
structure used to insert eggs into immature alfalfa seeds. A single larva develops within each seed
and destroys all contents, leaving only the seed coat.
If seed production is planned for the current season, alfalfa should be cut by May
15. Eliminate volunteer alfalfa along fence lines and roadsides by mowing or spraying
with herbicides. Complete seed harvest by mid-August to avoid late season when the
insect populations are highest. Do not store uncleaned seed through the winter as
it may be infested with chalcids.