Weevil Biology

Weevils are commonly known as snout beetles. There are over 60,000 species of weevils that may infest various areas of your home, commonly infesting the pantry and stored food products. Some species may infest your wood or just invade your home to find a place to overwinter and avoid the cold season.  Weevils are considered a nuisance pest and will enter the structure primarily in the fall season and leave in the spring. They may even enter in the spring season to avoid extreme and unfavorable outdoor conditions.

Description and Life Cycle

Generally, weevils will overwinter until the spring, even as eggs or larvae. Many species of weevils are parthenogenetic, which means they are able to reproduce without a male. Eggs are laid everyday by fully matured females and will lay about 1,600 in her lifetime. They will remain at the base of the plant or under leaf litter. When the eggs hatch after about 10 days, larvae will feed until the late fall season so that they can prepare to overwinter. Larvae are subterranean and feed on the roots, so they are rarely seen. When the spring season arrives, they will emerge and resume their feeding processes. This is why the most damage will be seen during the spring season. In the mid-summer season, the larva will begin to pupate and continue pupation for about 10 days. They will emerge in the late summer as adults. Weevils can start laying eggs only after about 2-3 weeks of feeding. Adult weevils will vary in size depending on the species, ranging from 3-11 mm long. They can be distinguished by their oval shape and their head elongated into a snout with mandibles. They also have antennae that is almost always elbowed or bent. Color will also vary depending on the species of weevil.

Food and Damage

Weevils will feed on a variety of plants depending on the species. For instance, the Asiatic Oak Weevil will feed on a variety of woody plants which will include oaks, beech, willow trees, sycamore, and etc. However, the black vine weevil will feed on a variety of other plants such as fruits like strawberries, grapes or other plants like hemlock and also such greenhouse plants like impatiens. Most of the damage done to the plants or the presence of these bugs will be noted by circular or crescent shaped notches and markings along the edges of leaves of the plants where the weevils have chewed through.


Date: Monday, 14. November 2011 14:46
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