Insecticidal Benzoylphenyl Ureas: Structure-Activity Relationships as Chitin Synthesis Inhibitors

Abstract
The 1-benzoyl-3-phenylurea insecticide diflubenzuron is a potent inhibitor for the conversion of 14C-labeled glucose to 14C-labeled chitin in isolated abdomens of newly emerged adult milkweed bugs (Oncopeltus fasciatus Dallas). The inhibitory activity of 24 diflubenzuron analogs in this in vitro chitin-synthesizing system is in good agreement with their toxicity to fifth instar nymphs of this species. These insecticides act quickly and directly within the integument to ultimately block the terminal polymerization step in chitin formation.