Pest Status: Hessian flies are important pests of cereal crops. Their management has dictated cropping practices such as the "fly-free date" for wheat throughout much of the country.
Appearance: Hessian fly adults are small, delicate, dark, long-legged, two-winged insects that somewhat resemble mosquitoes. Females are slightly larger than males (1/8-inch long) and their bodies have a red tint. Males are smaller and have two pairs of abdominal claspers.
Life Cycle: Adults emerge in mid-fall to mate and lay eggs. The larvae are present through late-fall and feed on juices that they extract from the base of nearby plants. They overwinter in the pupal stage and adults emerge in the spring.
Where to Collect: Hessian flies can be found in crop fields, particularly wheat, barley, and rye.
Purdue Extension Entomology, 901 West State Street, West Lafayette, IN 47907 USA, (765) 494-4554