Two simple chromenes with anti-JH activity have been isolated and identified from the bedding plant Ageratum houstoianum. By contact and fumigation these compounds induce precocious metamorphosis and sterilization in several hemipteran species of insects. Certain holometabolous species are sterilized, forced into diapause, or both. Each of these biological actions is equivalent to removal of the corpora allata, which produce the JH's, and is reversible by treatment with exogenous JH. Thus, the action of these compounds is to stop the production or depress the titer of the JH's. To our knowledge, this is the first discovery of anti-JH, and we hope it will guide the way to the emergence of a fourth generation of safe and insect-specific pesticides.

Cytotoxic agents with antijuvenile hormone activity in insects have been discovered. Their mechanism of action may involve an oxidative bioactivation into a reactive quinone methide.

Corpora allata of the African cotton stainer, Dysdercus fasciatus Sign. (Hemiptera: Pyrrhocoridae), produce radiolabeled methyl-l0,ll-epoxy-3,7,11-trimethyldodeca-2E,6E-dienoate (JH 111) when cultured in a medium containing L-[meth~l-'~C] methionine. Similar in vitro studies show JH TI1 biosynthesis by cultured corpora allata of Lygaeid and Pentatomid species. This is the first identification of a juvenile hormone in Hemiptera.