Evaluation of DIMBOA analogs as antifeedants and antibiotics towards the aphid Sitobion avenae in artificial diets

A total of 25 compounds including benzoxazinones, benzoxazolinones, and N-g lyoxylamide derivatives were tested as antifeedants and antibiotics towards the aphid Sitobion avenae in diet bioassays. The antifeedant and mortality indexes increased with the presence of electron-donating groups in the 7 p osition of the benzoxazinone moiety, the replacement of the oxygen atom by sulfur in the heterocyclic ring, the presence of a hemiacetal instead of an acetal at C-2 of the benzoxazine moiety land hence the possibility of ring opening), and the presence of a hydroxyl group at C-4 of the benzoxazine m oiety (hydroxamic acid) instead of a hydrogen atom (lactam). The results su pport earlier hypotheses on the chemical bases for the mode of action of th ese compounds.