Similar to both the Lygus Bug and Stink Bug.
Adults are about 0.25 inch (6 mm) long and 0.1 inch (2.5 mm) wide, and flattened on the back. They vary in colour from pale green to yellowish brown with reddish brown to black markings, and have a conspicuous triangle in the center of the back. Nymphs resemble adults, but are uniformly pale green with red-tipped antennae; larger nymphs have five black spots on the upper body surface. Nymphs do not have wings.
Lygus bugs pierce squares and damage anthers and other tissues. When squares are less than 0.2 inch long, they shrivel, turn brown, and drop from the plant. Damage to larger squares may be to anthers, styles, and stigma, and may interfere with fertilization. If many squares drop, the plant may put its energy resources into vegetative growth, resulting in tall, spindly plants and reduced yields.
Lygus bugs also feed on and destroy terminal meristems, causing bushy plants. If these bugs pierce the wall of young bolls (typically less than 10 days old) and feed on young seeds, these seeds may fail to develop. Lint around the injured seeds is stained yellow, and may not mature normally.
Stink bugs are medium to large-sized bugs. Those that attack small grains are commonly grey brown to green in color and 0.38 in. to 0.5 in. long. Their bodies have a characteristic shield shape with a large triangle on the center back.
They are most common where cereals are planted adjacent to rangeland near the foothills or desert. Damage usually occurs when stink bugs feed in the head during milk or soft dough stage.