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James R. Baker and S. Bambara, Extension Entomologists

CAUTION: This information was developed for North Carolina and may not apply to other areas.

[General Information] [Biology] [Control] [Other Resources

MARCH FLIES, Plecia nearctica, Bibio femoratus and other species, Bibionidae, DIPTERA

General Information

adult fliesMarch flies range from fragile to sturdy insects with relatively short antennae and dark bodies. Some species are marked with red or yellow spots. March flies are 1/4 to 1/2 inch long. March fly larvae are gray, leathery maggots with well defined heads. The body has numerous small bumps and protrusions. March fly maggots are 1/4 to 1 inch long.


maggot drawingMarch flies are found throughout North America. Large flights of March flies occur primarily in the southeastern United States. March fly maggots develop in decaying organic matter. Adults visit flowers presumably for nectar. The principal concern over March flies arises with the sudden appearance of swarms of these flies over ornamental and fruit crops and around homes. When their swarms cross roads and highways, large numbers splatter on trucks and automobiles. Visibility may be reduced, and when the flies are especially abundant, vehicles may overheat because the flies clog radiator fins. If left on car finishes too long, the fatty tissue of the flies and their eggs may pit or mar the paint.

After mating, female March flies enter the soil where they lay 200 to 300 eggs. The maggots hatch from the eggs and feed on leaf litter and sometimes among the roots of living plants. They have been reported from potatoes which had been previously damaged by wireworms. Their feeding hastens the breakdown of plant tissue into humus. March fly adults often emerge in early to late spring. (Sometimes there is a fall flight also.) These flies visit flowers and are sometimes effective pollinators.


The large scale control of immature or adult March flies by chemical means would place an undue pesticide load on the environment. The most troublesome species of March flies swarm during warm daylight hours, so driving at night may avoid the problem for travelers. A screen across the front of the radiator will protect the radiator from clogging. Temporarily smearing the front of the car with baby oil or spraying it with a no-stick cooking product will aid in the removal of splattered flies later.

Other Links:
Florida note

Tie a fly that mimics Bibio

Other Resources

For assistance with a specific problem, contact your local North Carolina Cooperative Extension Service.

Prepared by: James R. Baker & S. Bambara, Extension Entomologists

Published by North Carolina Cooperative Extension Service

Distributed in furtherance of the Acts of Congress of May 8 and June 30, 1914. Employment and program opportunities are offered to all people regardless of race, color, national origin, sex, age, or disability. North Carolina State University at Raleigh, North Carolina A&T State University, U.S. Department of Agriculture, and local governments cooperating.
© 2001 NC Cooperative Extension Service

August 1994 (Revised)May 1997

Web page last reviewed January, 2011 by the webperson.