Melanotus communis
Melanotus communis (Gyllenhal) (no common name), Elateridae, COLEOPTERA

DESCRIPTION

Adult - Melanotus communis is a hard, smooth-bodied, reddish-brown to black click beetle about 13 mm long.

Egg - The white, glistening egg is oval to spherical in shape and 0.33 mm long.

Larva - This short-legged wireworm has a pale yellow to reddish-brown body and a brown, flattened head. When mature, it ranges from 21 to 25 mm in length.

Pupa - The white, soft-bodied pupa has no protective covering and is approximately the same size and shape as the adult.

BIOLOGY

Distribution - Melanotus communis wireworms can be found throughout the United States, but are most abundant in the midwestern and southeastern states. They tend to be common in newly planted sod or no-till planted corn.

Host Plants - The wireworm, M. communis, feeds on the roots of many grasses including corn and many small grain crops. It may also attack the roots, seeds, and tubers of many flower and vegetable crops, especially potatoes. This species has been known to infest tobacco.

Damage - The most significant wireworm damage occurs to germinating seeds and seedling plants. Wireworms feed on the seed and often leave only the empty hull (pericarp). Roots are snipped off as they emerge and often rot. Corn seedlings 5 to 20 cm high are damaged when wireworms tunnel in or feed superficially upon the underground stem and taproot area of plants. Recent injury of this kind may be characterized by the presence of rot and jelly-like plant secretions. Above-ground symptoms include yellowing and wilting or death of terminal shoots. Melanotus communis does more damage during cold, wet springs, especially in fields which have been grassy or weedy for the previous year or more.

Life History - This wireworm species has a six-year life cycle. In June of the first year, adults deposit eggs singly among the roots of grasses. First instar larvae emerge in July and begin feeding on roots. The first year, larvae continue to develop throughout the summer and overwinter in the ground as second instars. Most of these immatures remain in the larval stage for 5 years although life cycles as short as 3 years have been reported. In late July or August of the sixth year, mature larvae construct oval cells 15 to 30 cm deep in the soil and pupate. Melanotus communis beetles emerge about 18 days later and feed on pollen before hibernating in protected areas. They become active and deposit eggs the following May or June.

CONTROL

Cultural methods of controlling wireworms include summer plowing of fallow fields and crop rotation. Plowing to a depth of 23 cm (9 inches) around the first of August will dry out the soil and break up the insects' cell-like chambers, killing large numbers of pupae and adults. Legumes are more tolerant to feeding by these pests and are therefore excellent crops with which to rotate corn. Rotating corn with small grains and planting crops in well-drained soils are additional control measures effective against Melanotus communis.

For specific chemical recommendations, consult the current North Carolina Agricultural Chemicals Manual.