Cotton - Spiny boll worm
Description
Stout, spindle-shaped caterpillar, greenish to brown with yellow/brown spots up to 18 mm long. The majority of segments have two pairs of fleshy tubercles, which make the caterpillar appear spiny.
Damage
Spiny bollworms may be present as shoot-tip borers early in the season. This damage may stunt ,plants or force an unnatural growth pattern, Normally, however, the plant compensates well for early season damage by producing new shoots and no effect is seen on yield from shoot-tip boring. Spiny bollworms prefer to feed on flowers and young bolls as these become available. Larvae move around the plant damaging several fruiting structures during their life.
Life cycle
Adult females lay 200-600 eggs singly on shoots of young plants, or on stalks, flower bud bracteoles and young bolls on older plants. Eggs hatch after 3-4 days and larvae pass through 5 instars during the ensuing 12-18 days. The last larval instar spins a dirty white to pale brown scaphoid, felt-like cocoon on the plant or among the plant debris on the soil surface. The pupal stage lasts for 1-2 weeks.