Corn Flea Beetle
Chaetocnema pulicaria Melsheimer, Chrysomelidae, COLEOPTERA


DESCRIPTION

Adult - This oval black beetle is tinged with bronze or bluish-green, has yellow markings on its legs, and is 1.3 to 2.5 mm long. The basal segment of each antenna is orange.

Egg - Each white egg is about 0.35 mm long and pointed at one end. It gradually darkens before hatching.

Larva - The slender, white, cylindrical grub has a brown head and tiny legs. It may be 3.2 to 8.5 mm long when full grown.

Pupa - The white, soft-bodied pupa resembles the adult in size and shape and gradually darkens as it matures.


BIOLOGY

Distribution - The corn flea beetle occurs in most areas east of the Rocky Mountains. It infests corn all across North Carolina but appears to be more abundant in the Piedmont counties.

Host Plants - Although the corn flea beetle is a general feeder, its preferred hosts are grasses. However, sugar beets are periodically infested in other states.

Damage - Corn flea beetles attack foliage leaving small round holes and bleached out spots or stripes; larvae feed on roots of grasses. Direct loss caused by these injuries, however, is relatively insignificant. The overwintering beetles which carry bacterial wilt of corn (Stewart's disease) are responsible for most economic damage because of the spread of this disease. These beetles are usually most troublesome after a mild winter followed by a cold spring. Under such conditions, large numbers of beetles survive the winter and attack slowly growing corn over a prolonged period. Growth is retarded and leaves may wilt. Early maturing varieties in the middle Atlantic and southern states are most seriously affected.

Life History - Adults generally overwinter in litter and trash around fields. Mortality tends to be high during harsh winters. In early spring, beetles move to weeds and then to corn seedlings. Eggs are scattered on soil beneath host plants. In about 10 days, larvae emerge and begin feeding on and tunneling in underground stems, roots, or tubers. They feed for 3 to 4 weeks and develop through 3 instars before pupating in the soil. Seven to 10 days later, a new generation emerges. Three or more generations are completed each year.


CONTROL

Damaging corn flea beetle infestations can be prevented by plowing under crop residue and maintaining good weed control to eliminate overwintering sites. The use of wilt resistant hybrids also lessens the chances of excessive loss due to bacterial wilt. For recommended insecticides and rates, consult the current North Carolina Agricultural Chemicals Manual.

Return to AG-295 Table of Contents