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United States Department of Agriculture

Agricultural Research Service

Boll Weevil
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The Boll Weevil, Anthonomus grandis grandis, is a major pest of cotton that feed on fruiting forms, leaf petioles, and terminal growth. They begin feeding on the terminals and leaf petioles, and then lay eggs in the cotton squares and later in the bolls. The larva within the squares and bolls stop the squares growth and the bolls don't open properly or get boll rot.

Characteristics
The larvae are grubs about 3/8 inches in length and white colored with brown heads. The adults vary from 1/9 to 1/3 inch in length and turn from reddish brown to dark gray or black over time. They have long, slender snouts with chewing mouthparts at the tip and two spurs on the upper joint of the front legs.

Life Cycle
Adults overwinter and emerge in the spring and summer, but peak in May, and females feed and mate for 3-4 days before laying about 200 eggs in 10 days. The newly hatched larvae feeds on anthers and pollen in the squaresor lint in the bolls and begin pupating in 7-12 days that lasts 3-5 days. Each generation lives about three weeks and has 8 to 10 generations per season.


Adult boll weevil on cotton boll Adult boll weevil

Last Modified: 5/3/2005
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