|Controlling Insect Pests of Stored Products Using Insect Growth Regulators and Insecticides of Microbial Origin (NRI, 1994, 58 p.)|
|Section 2: Insect growth regulators: general account|
Once the effects of JH and JHAs had been demonstrated, research
was directed towards determining the effect of their absence prior to the final
Bowers (1976) discovered that extracts from the plant Ageratum houstonianum cause premature metamorphosis in some Hemiptera. It was subsequently shown that the active molecules, or precocenes, destroy the glands (corpora allata) which produce JH after first being converted to highly reactive metabolites by tissue-specific enzymes within the glands (Menn et al., 1989).
Screening led to the discovery of anti-JHs such as fluoromevalonate (FMev). FMev showed activity against virtually all the Lepidoptera in which it was tested but little in other insect orders.
Although anti-JHs have become useful research tools, none have shown sufficient promise to be developed as practical pest control agents. Also, precocenes have been found to be toxic to the liver and kidneys of vertebrates (Steal, 1 986).