Alkylene-bis-isothiocyanates: Novel Insect Growth Regulators

In search for selective anti-insect agents some monoand bis-isothiocyanates were prepared and tested on third instar larvae of Manduca sexta. The alkylene-bis-isothiocyanates 4, 5 and 6 had a novel effect preventing formation of the abdominal spiracles and of the hooks (crochets) at the following molt to the 4th instar. Some of these larvae died in the molt, while spiracles remained absent also in the larvae which were able to molt to the 5th instar. Histological examination indicated a selective destruction of spiracle forming cells. This novel action might serve as starting point of a new approach in selective insect control.