The female moths lay clusters of about ISO whitish eggs, usually on the undersides of leaves. The egg masses are covered with fine scales from the female moth. Larvae may feed on leaves, blooms or pods. Most damage occurs when they eat the beans out of the pod. Adults have 2 pairs of membranous wings partially concealed beneath a hard projection arising from the front of the insect and extending backwards.
Nymphs have spiny projections arising over the body.
Both adults and nymphs have piercing-sucking mouthparts. They suck juices from the developing main stem near the soil line. Seedlings may be girdled and die or damaged plants may survive but lodge later in the season.