The Velvetbean Caterpillar, Anticarsia gemmatalis, is primarily a pest of soybeans, but also feeds on over thirty other pod producing plant species. They start feeding on the upper leaves and work down to the middle and lower parts. They can rapidly defoliate the entire leaf mass leaving only larger veins and midribs.
The larvae have a light, dorsal stripe bordered by dark stripes and a broad, white horizontal stripe on each side. They are usually a light green but can be brown or black. They grow to nearly 2 inches and have four pair of abdominal prolegs plus a pair of anal prolegs. They violently wiggle their abdominal prolegs when disturbed and is shown in the picture below. The moth has grayish or brown forewings and cinnamon brown hindwings with a submarginal row of light spots. They also have a diagonal black line when the wings are fully extended and a wingspan is between 1 and 1 1/2 inches.
They overwinter in tropical areas and migrate north each spring and early summer. Moths lay eggs singly or occasionally in small groups of 2-3 on the underside of leaves and hatch in about three days. The larvae feed for 15 to 30 days and pupate in the soil. A generation lasts about 4 weeks and they have 3 or 4 generations each year.