Why not use insecticides and acaricides (chemicals that kill ticks and other mites) instead of using repellents? Here are some of the drawbacks of pesticides.
Insects Avoid Pesticides
Most insecticides require that the target “bug” actually contact the poison in order to be effective. Insects avoid such chemicals by hiding in cracks and crevices, or on the underside of leaves. Insects also use their antennae to detect potentially hazardous chemicals and simply steer clear of residues.
Insects and ticks have such large populations that some individuals usually have genes that code for resistance to a given insecticide or acaricide. After non-resistant members of the population die, resistant ones breed and the next generation has more resistance.
Pesticides Kill Non-target Species
Insecticides kill indiscriminately. Many “good” bugs that kill the bad bugs will die from insecticides, too. Bees are also frequent victims of pesticides. Birds, bats, and other animals can die or suffer ill effects as well.
Because insecticides are usually broadcast over the landscape, the toxins easily enter the water supply as they filter to underground aquifers, or are washed into rivers, streams, and lakes by rains. Chemical spray applications are also blown by the wind.
You want to be sure to follow the instructions for applying repellents, too, but most people do not respect dosage when using over-the-counter insecticides. This is the number one problem with home pesticide use. The “more must be better” mentality can be lethal to you, your family, or your pets.
There is a reason they are called bug “bombs.” Foggers can destroy a home if one forgets to extinguish a pilot light, resulting in an explosion and/or fire. Household pests are best controlled through prevention and non-chemical treatments anyway.
Stay safe. Use EPA-approved repellents, and practice preventive measures when indoors and outside. Consult entomologists at museums, universities, and public health department for reliable identification of worrisome insects, ticks, or spiders.