Boll Weevil
Description:
The adults are brown to grayish brown, fuzzy beetles with prominent snouts (or bills)
bearing the mouthparts, and varying in size from 1/8 to almost ½ inches long. Larval stages,
found inside cotton squares and bolls, are legless grubs with brown heads that grow to about ½
inch long before forming a pupa that resembles the adult features but appears mummy-like.
Life cycle:
Adults overwinter, or "diapause," in leaf litter and fly to cotton fields in the spring. After feeding for 3 to 7 days, weevils mate and females lay eggs in cotton squares (flower buds) or bolls (fruit) that are 1/4 inch or more in diameter.
Larvae hatch in 2 ½ to 5 days, and larvae feed for 7 to 14 days and
develop through several stages (instars) before pupating.
Adults emerge in 4 to 6 days and chew their way out of the cotton square or
boll in which they developed. Development from egg to adult can be completed
in 16 to 18 days. Six or seven generations can be produced each year.
Pest Status:
Caused major changes in cotton production practices since it migrated into and across Texas and Oklahoma.
Larvae feed in cotton squares and bolls.
Control:
Traditional boll weevil controls included diapause control (sprays and stalk destruction
immediately after harvest to prevent weevils from entering diapause),
insecticide application at pin-head square stage (to reduce populations of overwintered
weevils prior to oviposition), and four to five mid and late season insecticide applications
at 3 to 5 day intervals, beginning as early as first bloom.
