Striped Flea Beetle
Phyllotreta striolata (Fabricius), Chrysolmelidae, COLEOPTERA

DESCRIPTION

Adult - This small black beetle, 1.5 to 2.5 mm long, has a wavy yellow line running the length of each wing. The hind legs are thickened, enabling the beetle to jump.

Egg - The minute, oval to elongate egg is white.

Larva - When fully grown, the white, brown-headed larva is 3.2 to 5.0 mm long. It has 3 pairs of tiny legs near its head.

Pupa - The tiny white pupa is approximately the same size and shape as the adult.

BIOLOGY

Distribution - The striped flea beetle is common throughout the eastern and Pacific areas of the U.S. and is Eurasian in origin. It is not common in much of the Rocky Mountain regions.

Host Plants - Striped flea beetles infest many crucifers but prefer mustard, turnip, radish, and related weeds.

Damage - Although larvae feed on the roots of host plants, the primary damage is caused by adult beetles feeding on foliage. Beetles make small pits in leaves. The remaining thin layers of tissue eventually dry up and fall away leaving small "shot holes" in the foliage. This type of injury is capable of killing young plants. In addition, beetles may act as vectors of plant disease.

Life History - Striped flea beetles overwinter among debris in and around fields. Emerging early in spring, they attack seedlings and young plants. Eggs are deposited in tiny crevices gnawed out of the base of host plant stems. About 10 days later, grubs hatch from the eggs and move into the soil to attack roots. After feeding for 3 or 4 weeks, the larvae pupate for 7 to 10 days. A new generation of beetles then emerges. There are at least two generations each year in North Carolina.

CONTROL

Cultural practices and the use of resistant varieties help prevent severe flea beetle infestations. Stripes of gauze physically protect seedbeds from flea beetles. Good weed control and the destruction of crop residue reduce overwintering populations. The use of resistant varieties may reduce injury by existing beetles. Such varieties include: Stein's Early Flat Dutch, Mammoth Red Rock, Savoy Perfection Drumhead, Early Jersey Wakefield, Copenhagen Market 86, and Ferry's Round Dutch (cabbage); Vates and Georgia (collards); Florida Broadleaf (mustard); American Purple Top (Rutabaga); Snowball A and Early Snowball X (cauliflower); DeCicco, Coastal, Italian Green Sprouting, and Atlantic (broccoli); Vates, Dwarf Siberian, Dwarf Green Curled Scotch, and Early Siberian (kale).

Chemical treatments for control of flea beetles should be applied as needed. For recommended insecticides and rates, consult the current North Carolina Agricultural Chemicals Manual.

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