Problem Identifier Unit Screen//v.w/ RR Template

Problem Identifier Unit Screen//v.w/ RR Template Corn Rootworm

Problem
Yellow, pale green, or brownish red beetles with very long antennae crawl on the plants. Some may have black spots or stripes. The ears are malformed, with undeveloped or partially developed kernels; leaves may be chewed.

Analysis
(Diabrotica species)

Both adult beetles and young worms of this pest attack corn. For information on the larva, see Corn Rootworm Larvae. The adult beetles feed on the pollen, silks, and tassels, resulting in malformed ears and undeveloped kernels from improper or incomplete pollination. Some beetles may also feed on the leaves. The adults lay yellow-orange eggs in the soil at the base of the corn plants. The young worms that hatch from these eggs feed on the corn roots for several weeks, then pupate in the soil to emerge as beetles in late July and August. These pests are most common where corn has grown consecutively for 2 or more years. Late-planted corn and corn under drought stress are the most susceptible.

Solution
Dust the plants with an insecticide containing carbaryl when the beetles first appear on the plants. Repeat at weekly intervals if the plants become reinfested. Control the rootworm larvae as suggested in Corn Rootworm Larvae.

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