Weevil

 Banana Weevil

I.Banana Weevil, //(Cosmopolites sordidus.)//


 * A. General Description-**

A weevil is any beetle from the Curculionoidea superfamily. They are usually small, less than 6 mm (¼ inch), and herbivorous. Due to the shape of their heads, weevils are commonly known as snout beetles.

B. **Detailed Description-** Weevils (Curculionidae) comprise a very large group of insects that are closely related to beetles (order Coleoptera); more than 40,000 species are recognized worldwide, ranging in size from 0.2-2 in (0.5-5 cm). A weevil is easily distinguished from a beetle by its extended head, which forms a rostrum, and long, segmented antennae that are clubbed at the end and are usually bent in an elbow fashion near the base. Most species have a dull colouration—commonly brown, gray, or buff—but others are more brilliantly decorated with tinges of reddish brown, pale green, and blue. The body of most weevils are covered with a mass of tiny scales that give these insects an iridescent color. Adults usually have two pairs of wings, although several species are wingless and the elytra (wing cases) are fused together. Males are often smaller than females.

Weevils are often found in dry foods including nuts and seeds, cereal and grain products. In the domestic setting, they are most likely to be observed when opening a bag of flour although they will happily infest most types of grain including oats, barley and breakfast cereals. If ingested, E. coli infection and other various diseases can be contracted from weevils, depending on their diet.

In view of their life history, weevils are of considerable economic importance, particularly in relation to agriculture. No part of a plant, from the roots to the seeds, is safe from the attacks of one or more species of weevil. Although it is mainly the larval stages that cause the most damage, the adults too can be quite destructive. Some species, such as the grain weevil (//Sitophilus granarius//), are serious pests of stored grains. Others, such as the cotton boll weevils (//Anthonomus barbirostris//), are responsible for widescale destruction of stored cotton in the United States, into which it was introduced in the 1890s from Latin America.

C. **Habitat and Distribution**

Weevils are found on every continent except Antarctica. They are also found on most islands. Most species prefer certain kinds of soils, climates, and foods and live only in a particular geographical region. A few weevils species have been distributed well beyond their natural distribution through human activity, either accidentally or on purpose. About twenty-five thousand species are known in the United States and Canada.

D. **Impacts** Negative- Seed pods were collected from 15 plants in September 2007, measured, and examined for intact seeds, damaged seeds, and weevils. Adult weevils were present in 46% of pods examined. More than 40% of predated pods contained two or more weevils. Pods contained an average of 9 seeds each, but two-thirds of the seeds were damaged by predation. Seeds of many species of plants are eaten by larvae of the weevil, impacting plant fitness and compromising prairie restoration activities.

E. **History**

The boll weevil, Anthonomus grandis Boheman, is a native of Mexico and Central America. It was first introduced into the United States near Brownsville, Texas, in about 1892.

By 1922, the pest had spread into cotton growing areas of the United States from the eastern two-thirds of Texas and Oklahoma to the Atlantic Ocean. The boll weevil colonized northern and western portions of Texas during a subsequent range expansion that occurred between 1953 and 1966. By 1981, the insect was well established in parts of California, northwestern Mexico and Arizona.

