Abstract
A mixture of the cis and trans forms of propylure (10-propyl-trans-5,9-tridecadienyl acetate), the sex pheromone of the female pink bollworm moth, has been separated into its pure isomers by thin-layer chromatography. The cis isomer inhibits or masks the activity of the trans isomer, as little as 15 percent of the cis isomer being sufficient to completely nullify the activity of the trans isomer.