To repel insects, products attempt to change a surface that is naturally attractive to bugs into one that is undesirable. Insect repellents are designed to discourage bugs from landing where they have been applied. Smell is believed to be the strongest draw for insects, so repellents try to replace scents that attract, with ones that keep bugs away.
Humans are a prime target for insects, possibly because many bugs, mosquitoes in particular, are drawn to carbon dioxide. Carbon dioxide is a chemical compound given off by humans. To repel insects, products are applied to skin or clothing attempting to mask this scent.
Many readily available products claim to repel insects. Repellents can be applied to skin and clothing in the form of a sprays, lotions, foams or sticks. Wipe-on repellents are available, as well as repellent candles and coils to be burned. The active ingredients used to repel insects are either synthetic chemicals or plant derivatives.
The chemical DEET is widely believed to be the most effective way to repel insects. The protection it offers in repelling bugs needs to be balanced with its toxic properties. DEET product label warnings and precautions should be read and considered. DEET is the active ingredient in many forms and brands of insect repellent.
Products also make use of plant derivatives to discourage insects from making contact. Citronella oil, a liquid derived from various grasses, is a commonly used insect repellent. Citronella oil emits a distinctive, strong odor thought to confuse insects. Natural plant repellents are generally considered to be less effective than those containing DEET. Natural plant products need to be applied more frequently and produce a stronger scent than chemical alternatives.
Other plant derivatives thought to have natural insect repelling properties include the oils of clove, peppermint, cedar, rosemary, garlic and cinnamon. Lemon eucalyptus extract is also thought to have insect repellent properties. Insect repellents utilizing these ingredients can be purchased or made at home.
Bug zappers are devices that use fluorescent light to attract bugs to them. Bugs fly into the light and are met with an electric current that kills them. Some bug zappers also give off carbon dioxide providing additional bait. Bug zappers are controversial as they do not repel insects, but attract them. Some believe the disadvantage of attracting more bugs to an area outweighs the advantage of the ones killed.