Grasshoppers
Differential grasshopper, Melanoplus differentialis (Thomas);
Twostriped grasshopper, Melanoplus bivittatus (Say);
Redlegged grasshopper, Melanoplus femurrubrum (De Geer)
Acrididae, ORTHOPTERA


DESCRIPTION (several species)

Adult - Fully grown grasshoppers range in length from 19 to 38 mm. Coloration varies with species. Redlegged grasshoppers are reddish brown with a yellow underside. The differential grasshopper is basically brownish yellow or olive green with contrasting black markings on the hindlegs which distinctively resemble chevrons. Greenish yellow in color, the twostriped grasshopper has two pale stripes running down its back from the head to the wing tips. Color plate.

Egg - Egg pods are oval to elongate and often curved. Often the size of kernels of rice, eggs may be white, yellow-green, tan or various shades of brown depending on the species.

Nymph - Nymphs resemble small, wingless adults. Newly hatched nymphs are white; however, after exposure to sunlight, they assume the distinctive colors and markings of adults.


BIOLOGY

Distribution - Grasshoppers occur throughout the continental United States. Extensive grasshopper damage to crops, however, is fairly restricted to subhumid, semiarid areas which receive 25.4 to 76.2 cm (about 10 to 30 inches) of rain annually. Such an area includes the states from Montana and Minnesota, southward into New Mexico and Texas. Although common in North Carolina, grasshoppers seldom pose a severe threat to crops in this state.

Host Plants - These three species of grasshoppers are general feeders which attack many kinds of plants. They are known to cause losses in small grains, corn, alfalfa, soybeans, cotton, clover, grasses, and tobacco.

Damage - Although approximately 600 species of grasshoppers occur in the United States, the 3 species covered in this note are the damaging species most likely to be found in North Carolina. Grasshoppers rarely damage the commercially valuable parts of crop plants. They occasionally cause injury to small grains by feeding on stems, causing heads of grain to be snipped off. The most common damage in North Carolina occurs to forages and around the margins of corn and tobacco fields. Color plate.

Life History - Economically important grasshoppers overwinter as eggs in the soil. Eggs hatch throughout April, May and June as soil temperatures rise and spring rains begin. The first nymph to hatch out of the egg pod leaves a tunnel from the pod to the soil surface, making emergence easier for the nymphs which follow. Nymphs feed and grow for 35 to 50 days, molting five or six times during this period. Development proceeds most rapidly when the weather is warm and not too wet.

Two weeks after mating, females begin to deposit clusters of eggs in the soil. During the process, a glue-like secretion cements soil particles around the egg mass forming a protective "pod." Each pod may contain 15 to 150 eggs depending on the species of grasshopper which laid them. Under optimum conditions, each female produces 300 eggs. Generally, agriculturally important grasshoppers produce only one generation per year. Redlegged grasshoppers, however, have two generations per year plus a partial third in Florida.


CONTROL

Several cultural practices help prevent the buildup of high grasshopper populations. Spring or fall tillage destroys many overwintering eggs either by burying them deeply or by exposing them to the sun and air to dry. Where practical, fall plowing has the added advantage of making soil unsuitable to further egg-laying. In North Carolina, grasshopper populations in small grains are seldom large enough to warrant chemical control. When such populations occasionally occur, consult current North Carolina State Agricultural Extension Service recommendations.