Grasshopper eggs: A grasshopper egg cluster (Photo Marlin E. Rice)
Grasshopper eggs are deposited as a cluster in the soil in an earthen cell, which is held together by a foamy secretion. Individual eggs are elongate and generally light brown in color. Redlegged and differential grasshoppers lay 25-30 and 50-150 eggs, respectively.
Grasshopper nymphs: Differential grasshopper, Melanoplus differentialis, (left) and redlegged grasshopper, Melanoplus femurrubrum, (right) nymphs. (Photos Marlin E. Rice)
There are two common grasshoppers in soybean in Iowa, the differential grasshopper, Melanoplus differentialis, and the redlegged grasshopper, Melanoplus femerrubrum. These pest are paurometabolous with the immature stages (or nymphs) resembling the adults. One way to easily distinguish the nymphs of these two species is to look for a prominent, continuous black stripe that runs from the side of the thorax, across the side of the head, and seeming to pass through the eye of the redlegged grasshopper. The differential grasshopper nymph may have a small black mark on the side of the head but not a solid stripe along the side of the head as in the redlegged grasshopper.
Differential, redlegged, and twostripped grasshopper adults: Adult differential (top), redlegged (middle), and twostripped (bottom) grasshoppers; Melanoplus differentialis, M. femurrubrum, and M. bivitatus, respectively. The differential and redlegged grasshoppers are occasional pests of soybean and the twostripped grasshopper is rarely a pest. (Photos Marlin E. Rice)
The adult forms of these grasshoppers are very distinct. Differential grasshoppers, about 28-50 mm in length (Capinera et al. 2004), are generally a dark mustard yellow or olive green in color with highly contrasting, black chevrons marking the outside of their femur (the thickest segment of their hind legs). Redlegged grasshopper adults are about 17-30 mm long and distinguished by having a bright red tibia on the hind leg (the slender leg segment following the femur) (DeGooyer and Browde 1994) and a black bar immediately behind the eye. In both species the female is larger than the male.