ABSTRACT
Insect growth regulators (IGRs) are chemical insecticides that disturb insect-specific, sometimes mite-specific, physiological processes that do not exist in vertebrates, including humans. Current commercial IGRs are chitin synthesis inhibitors (CSIs), interfering with molt, juvenile hormone analogs (JHAs) that disturb metamorphosis and/or prevent reproduction, and ecdysone (ecdysteroid) agonists that induce an untimely lethal molt. Anti-juvenile compounds also exist but are not produced commercially. IGRs are highly advantageous to the environment; they are nontoxic, or slightly toxic (often as at g/kg level), to vertebrates; and the range of lethally affected species is much more limited than that of the conventional insecticides. Some disadvantages of IGRs, such as lethal or sublethal effects on nontarget species and development of resistance and cross-resistance, do not differ from those of conventional insecticides. A specific disadvantage of IGRs is that in most cases, their effects are belated and a pest may inflict additional damage before mortality takes place. Also, persons who use an IGR do not see an immediate knockdown of the pest and therefore doubt the effectiveness of the IGR. It is concluded that in most instances, IGRs are much friendlier to the environment than conventional insecticides.
