Wheat Insects

False Wireworms (Tenebrionidae)

False wireworm larva

False wireworm beetle, Eleodes hispilabris.

False wireworm beetle, Eleodes suturalis.

False wireworm beetle, Eleodes tricostata.

Scalloped false wireworm beetle, Embaphion muricatum.

Introduction

False wireworms are the larvae of darkling beetles. There are several species that occur west of the Mississippi River, including several species in the genus Eleodes. In Kansas, they occur primarily in the western two-thirds of the state.

Description

False wireworms are the larvae of several species of darkling beetles (Family Tenebrionidae). Adults are large (about 1 inch in length), dark-colored, long-legged beetles that often can be seen running over the ground and hiding under litter in continuous wheat fields. Adults vary in appearance and size. Most species have antennae with eleven segments. Adults have 5 tarsal segments on the first 2 pairs of legs and only 4 tarsal segments on the third pair. The wing covers may be ridged, smooth or granulate, and are fused together so the adults can't fly. When disturbed, the adults have a peculiar habit of placing their head near the ground and elevating their abdomen in the air as if they were trying to stand on their head. The larvae closely resemble wireworms in appearance, slender with noticeable segments, but they have longer legs and antennae than true wireworm larvae. The larvae range from yellowish-brown to nearly black, depending on the species.

Life History

False wireworms overwinter as partially grown larvae or adults. Adults become active in the spring and lay their eggs in the soil. Larvae from these eggs hatch and mature by the end of the summer. A second egg-laying period occurs late in the summer. These eggs hatch and the partially grown larvae from this second generation will overwinter along with the surviving adults. The larvae feed on seeds, roots and underground stems of their hosts. With wheat, they usually attack the seed before germination. In dry soils, one larva may follow the drill row and destroy several seeds by eating out the germ causing bare patches in the field. Characteristic damage is seed with the ends nibbled on and the germ removed. Losses can be severe when persistent dry weather in the fall delays sprouting. Additional damage may occur the following spring. False wireworms pupate in earthen cells in the soil. The adults can live up to three years.

Management Practices

To detect problems before planting, sample five to 10 places in a field by sifting 1 square foot of soil dug to a depth of 4 inches through a piece of hardware cloth with 1/4-inch mesh. An average density of one larva per 3 square feet, suggests an infestation of economic importance. Although a wide range of plants serve as food, crop rotation out of wheat to other cultivated crops for at least two years may reduce damage relative to continuous wheat. Piles of decomposing straw and vegetation provide attractive shelter for adults and should be removed. False wireworms can be a perennial problem and fields with a history of damage should be planted with treated seed. Treating wheat seed with insecticides has been an inexpensive and effective means of controlling damage from these insects. Other chemical control procedures are not known to be effective. For example, seed Treatments based on imidacloprid (Gaucho, etc) and thiamethoxam (Cruiser) are not labeled for false wireworm control, and reportedly do not adequately control these pests.

Phillip E. Sloderbeck, J.P. Michaud, and R. Jeff Whitworth, July 2007

*Photos in this document are by the by the Kansas Department of Agriculture from the PDIS web site and are Copyrighted by Kansas State University Research and Extension - visit the PDIS web site for image use policy.

Page last updated 10/30/2013 by J.P. Michaud.