The adult short-cycle moths live about 14 days. However, some moths may live as long as 31 days with an average oviposition period of about 7 days. The adults are most active at night, seek shelter during the day, and are seldom seen in an infested field.
Males respond to a pheromone released by the female prior to mating, which may occur the first night after emergence and one or more times thereafter. Most mating takes place after midnight. The greatest oviposition activity in the cotton field occurs in the evening between 8 and 10 p.m. Bolls 10 to 20 days old are the preferred ovipositioning site. Eggs laid on the bolls may be deposited singly or in clusters. Egg clusters on a boll may contain only a few or as many as 75 to 100, overlapped in a shingle-like configuration.
The larva of the pink bollworm is the life stage that is injurious to cotton. It passes through four and sometimes 5 instars before attaining a length of about ½ inch when fully grown. The length of time spent in the larval stage characterizes the individual larva as “short-cycle” (summer brood) or “long-cycle” (resting stage). The newly-hatched larva is almost colorless except for the brown head capsule. It enters the fruiting form of the cotton plant shortly after hatching and is seldom seen outside the fruiting form. Coloration darkens as the larva grows until it reaches a deep pink at maturity. After the short-cycle or non-diapausing larvae complete their feeding period, they leave the fruiting forms and drop to the ground where they spin a silken cocoon and pupate in surface trash or in the soil. Most diapausing larvae remain in the boll. These larvae usually remain in a single seed, but sometimes spin a cocoon tying two seeds together, which resembles a double seed.
The larva spins a cocoon and may or may not pupate. The pupa is reddish brown, about 8 to 10 mm long and covered with fine pubescence. The pupal stage is usually 8 to 10 days.
Illustration - Pink Bollworm Life Cycle
Chronology of the pest in the United States
Technical Working Group