Insecticide Resistance--A Practical Assessment

During the last three to four decades, numerous insect species have been exposed to a series of new and more toxic insecticides. After many years of exposure to certain insecticides in the field, assays of some insect populations now show decreased susceptibility to those toxicants. The response of insects to the continued exposure to various insecticides has resulted in a phenomenon well known to all entomologists as insecticide “resistance.” Resistance, according to Crow (1957), designates a genetic change which is a response to pesticide selection.