boll weevil

boll weevil or cotton boll weevil bōl [key], cotton-eating weevil, or snout beetle, Anthonomus grandis. Probably of Mexican or Central American origin, it appeared in Texas about 1892 and spread to most cotton-growing regions of the United States. Over the years the weevil became a significant pest, destroying about 8% of the annual U.S. cotton crop. Boll weevil devastation was a major reason for diversification of the South's historic cotton economy. In 1978, however, the U.S. Dept. of Agriculture began a concerted eradication campaign. By the end of the century the weevil had disappeared from from most of the nation except Texas, Louisiana, and Mississippi, where the campaign continued.

The young adult is grayish, darkening with age, and about 1⁄4 in. (6 mm) long, with a long snout for boring into the cotton boll, or seed pod, where weevils feed on the cotton fibers. Weevils may also invade cotton flower buds before they mature into bolls. Females lay eggs within the bud or the boll, where pupation (see insect) occurs. The larvae eat the entire contents of the boll. Metamorphosis from egg to adult takes about three weeks; from 2 to 10 generations occur each season. The weevil's resistance to some poisons, and the removal of some poisons from the market, have encouraged Integrated Pest Management, e.g., the use of safer insecticides, synthetic growth regulators, and pheromone traps, and the release of sterile males to frustrate reproduction. Adults are also controlled by elimination of field litter, especially cotton stalks, in which they overwinter. Short-season cotton, bred to mature early, escapes much damage from weevil larvae.

The boll weevil is classified in the phylum Arthropoda, class Insecta, order Coleoptera, family Curculionidae.

See P. P. Sikorowski et al., Boll Weevil Mass Rearing Technology (1984); G. Matthews and J. Tunstall, Insect Pests of Cotton (1992).

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