Thiazolylureas: effects on larval growth and development in the fall armyworm and tobacco budworm

Prolongation of development caused size and weight increases in both larvae and pupae surviving treatment. Thiazolylurea 1 elicited similar growth and development effects in the tobacco budworm but was not as toxic to larvae. Structure-activity relationships were determined by testing 37 analogues of 1 against the fall armyworm. Compound 7, the diisopropyl ester analogue of 1, was the most effective compound against the fall armyworm, with growth-regulating effects observed at a dietary concentration as low as 1 ppm