These maggots damage seeds and seedlings of beans, corn, peas and various vegetable crops. Considerable injury and stand loss occurs in early planted beans. It overwinters as a pupa in soil close to old roots where it developed.
Adults emerge in the spring as early beans are being planted.
Females lay eggs, which hatch in less than a week, in moist soil containing decaying plant material upon which the young maggots feed. If sprouting seeds are near, maggots are attracted to them. Seeds with damaged germs die or develop into deformed plants which give low yields. Maggots that attack after seeds sprout bore into the stem, usually causing the plant to wither and die. In early spring, if soil is wet and cold during seed sprout, damage is especially severe.