Weevil, a tiny beetle that does enormous damage to growing plants and stored grains. There are more than 40,000 known species of weevils. The mouthparts of a typical weevil are formed into a long snout. There is an antenna on each side of the snout. In a number of species, the snout is longer than the body, which seldom grows to half an inch (13 mm) in length.

Grain weevilsGrain weevils eat wheat and other seeds.

The snout is used not only for feeding but also for making cavities in which the eggs are laid in buds, fruits, seeds, stems, and roots of plants. When the grubs (larvae) emerge, they feed within the plant parts. Infested fruits fall from the trees, or become stunted, scarred, or wormy, and are generally unfit to eat. Buds and seeds are destroyed by weevils and their larvae, and plants are weakened by their attacks.

The boll weevil is the chief insect pest of cotton. .) The plum curculio attacks plums, peaches, cherries, and apples. The alfalfa weevil is a destructive pest of alfalfa. The rice weevil and the grain weevil feed on stored small grains and lay their eggs within the grains. The acorn weevil feeds on acorns.

Control measures include burning infested plants and plant parts and spraying with chlordane and other insecticides.

Is the Weevil Really Evil?

Yes, weevils are evil beetles—as far as gardeners and farmers are concerned. If the ladybug does good by eating other insects, the weevil does harm by eating plants.

Name almost any grain, fruit, or vegetable, and it is likely that at least one kind of weevil enjoys eating it. The boll weevil eats cotton. The granary weevil eats wheat and other seeds. The rice weevil goes after rice and other cereals. One kind of fruit weevil chomps on apples, cherries, and plums.

The weevil damages plants in two ways. First, it chews its way into the plants. Then it lays its eggs in the hole it has made. When the eggs hatch, the larvae eat through the plants from the inside out.

Why Do Weevils Have Such Big Snouts?

A weevil’s snout, or nose, is curved downward so that it can bore into plants. At the end of the long snout are the weevil’s mouth parts that chew fruits, seeds, and other plant parts.

Different kinds of weevils have different kinds of snout shapes. Each shape is adapted to eating certain plants or parts of plants. For example, the female nut weevil’s snout is often longer than its body. It needs a long snout to bore through the hard shell of a nut and to lay its eggs inside.

The boll weevil is Anthonomus grandis; plum curculio, Conotrachelus nenuphar; alfalfa weevil, Hypera postica; grain weevil, Sitophilus granarius; rice weevil, S. oryzae; acorn weevil, Curculio rectus. These weevils are snout beetles, or snout weevils, forming the family Curculionidae of the order Coleoptera. Seed weevils, which are smaller than snout beetles and lack the snout, form the family Bruchidae. The cowpea weevil, Callosobruchus maculatus, is an example.