weevil

weevil - WEEVILS rostrum 1mm The weevils form a large...

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WEEVILS The weevils form a large family of beetles. There are 35,000-40,000 species in the family. In all species, the front part of the head is extended to form a beak or rostrum with a pair of biting jaws at the end. The main function of the rostrum is to bore holes in plants. In these holes, the female lays her eggs. The eggs hatch into larvae, which eat the plant material surrounding them. If this material is a crop plant or seeds used for human food, the weevils may cause serious damage. The bean stem weevil ( Alcidodes leucogrammus ), bores into the base of the stem of french bean (Phaseolus) or cowpea (Vigna) plants and lays a small number of eggs. These hatch in about 6 days to larvae similar to the one in the figure. The larvae feed on the stem tissue and damage the plant, sometimes causing the stem to break off or fall over. They pupate in the stem and emerge as adults in about 50 days, though this period is very variable. This weevil may attack and damage several rows of garden beans but it is not usually a serious agricultural pest. Burning
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This note was uploaded on 11/29/2011 for the course BIO 218 taught by Professor Young during the Fall '11 term at BYU.

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weevil - WEEVILS rostrum 1mm The weevils form a large...

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