Description
Beetles are members of the order Coleoptera, which is the largest insect order, containing 40 percent of all insects. The shiny or dull insects are easily recognized by their tough, leathery wing covers, called elytra. The wing covers meet in the middle of the back, forming a straight line down the insect's body. Some beetles, distinguished by their long snouts, are also called weevils or curculios. When beetles are at rest, the elytra hide a pair of clear, membranous wings. Some beetles don't have functional wings, and can't fly. The larvae of beetles are sometimes called grubs. Those grubs that have legs usually have three pairs. The larvae of weevils and curculios are legless. Both the larvae and adults may be harmful to plants. They have chewing mouthparts, and feed on plant tissue, other insects, or as scavengers. Plant feeders may devour any part of the plant. Some beetles feed inside the leaf tissue as leafminers (see Leafminers), borers (see Bark Beetles and Borers), or bark beetles (see Bark Beetles and Borers). Others feed outside the plant or on the roots.
Control
There are many methods of controlling beetles, depending on the part of the plant they infest. Control measures are often aimed at the adults, because grubs may be hidden or protected from chemicals inside plants or in the ground. Several different insecticides, including malathion, carbaryl, and diazinon, are used to control adult beetles. Look under the entry for your specific plant.
