Beets: Flea Beetles

Problem
Leaves are riddled with shotholes about 1/8 inch in diameter. Tiny (1/16 inch), black beetles jump like fleas when disturbed. Leaves of seedlings and eventually whole plants may wilt and die.

Analysis
These beetles jump like fleas, but are not related to them. Both adult and immature flea beetles feed on a wide variety of garden vegetables. The immature beetle, a legless gray grub, injures plants by feeding on the roots and the lower surface of leaves. Adults chew holes in leaves. Flea beetles are most damaging to seedlings and young plants. Leaves of seedlings riddled with holes dry out quickly and die. Adult beetles spend the winter in soil and garden debris. They emerge in early spring to feed on weeds until vegetables sprout or plants are set in the garden. Grubs hatch from eggs laid in the soil and feed for 2 to 3 weeks. After pupating in the soil, they emerge as adults to repeat the cycle. There are one to four generations a year. Adults may feed for up to 2 months.

Solution
Control flea beetles with an insecticide containing carbaryl or an insecticidal soap when the leaves first show damage. Watch new growth for further evidence of feeding, and repeat treatments at weekly intervals as needed. Remove all plant debris from the garden after the harvest to eliminate overwintering areas for the adult beetle.