Methoprene is a pesticide that acts as a juvenile hormone agonist. Although developed initially against insects, it has since been shown to have toxic effects on larval and adult crustaceans. Methoprene was one of the several pesticides applied to the Western Long Island Sound (WLIS) watershed area during the summer of 1999. Methoprene is a racemic mixture of two enantiomers (R and S in a ratio of 1:1). The activity of the compound as a juvenile hormone is restricted to the S enantiomer. Recent data have been describing the male sexual enhancement after methoprene treatment in Anastrepha fraterculus (Diptera: Tephritidae). It has been shown, that a sustained response doesn`t not fade away after sexual maturation, thus the potential benefits of using methoprene to increase the efficiency of the sterile insect technique, which is an environmentally safe method to control this fruit pest, have been proposed.