bollworms

Bollworms are the larvae of several noctuid moths that feed on cotton bolls and other crops. The term most often refers to the cotton bollworm, Helicoverpa armigera, a highly polyphagous pest with a broad distribution in tropical and subtropical regions. Other species commonly called bollworms include Helicoverpa zea (corn earworm), Pectinophora gossypiella (pink bollworm), and Heliothis virescens (tobacco budworm).

Life cycle: Adults are nocturnal moths that lay eggs on leaves or fruit. Hatching larvae feed for 2–4 weeks, damaging buds, squares, bolls, and seeds, and often entering protected parts of the fruit. After pupating, adults emerge to repeat the cycle. The number of generations per year depends on climate, with warm areas supporting multiple generations.

Damage and impact: Bollworms reduce yield and quality by feeding inside bolls; they also facilitate secondary infections. Pink bollworm is a major cotton pest in many regions, sometimes prompting quarantine and eradication programs. Because they feed across crops, bollworms can cause problems in cotton, corn, tomatoes, and other hosts, contributing to economic losses for farmers.

Management: IPM approaches include monitoring with pheromone traps, field scouting, crop sanitation, and resistance management. Bt crops expressing Cry toxins have reduced bollworm damage in some areas, but resistance can develop. Biological controls (parasitoids, Bacillus thuringiensis, and viral pathogens) and selective insecticides are used judiciously, together with crop rotation and sanitation to reduce survival and spread.