Pest description and crop damage Diamondback larvae are about 0.31 inch when fully grown. The larval body is wider in the middle and tapers at both ends, with two legs (prolegs) on the last segment forming a distinctive V-shape at the rear end. They feed mostly on outer or more mature leaves of older plants, chewing out small holes, or at growing points of young plants. They also feed on floral stalks and flower buds. Adult moths are small, slender, and grayish brown. Male moths display three diamond-shaped markings on their back.