Boll Weevil

Anthonomus grandis grandis

The size of a mature boll weevil varies according to the amount of food it receives during its larval stage, but it averages about 6 mm (1/4 inch), including the long, curved snout, which is about one-half the body length. In the spring, adult boll weevils emerge from a partly dormant state, and their light yellow colour changes to gray or black over several weeks. Females deposit between about 100 and 300 eggs in cotton buds or fruit, though they avoid depositing their eggs in cotton bolls already visited by other females, unless most of the bolls are infested. An average of two to three weeks is required for an egg to develop into an adult, and there may be up to 10 generations each year. The larvae live entirely within the cotton boll, destroying not only the seeds but also the surrounding cotton fibres. Because the larvae and pupae remain inside the cotton bolls for their entire period of development, the application of insecticides at that time is ineffective.

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