Structure Activity Relationships of Phenyl Alkyl Alcohols, Phenyl Alkyl Amines, and Cinnamyl Alcohol Derivatives as Attractants for Adult Corn Rootworm (Coleoptera: Chrysomelidae: Diabrotica spp.)

Abstract

In field trapping tests, phenyl alkyl amines and phenyl alkyl alcohols with 2-carbon side chains attracted significantly more adult females of the northern corn rootworm, Diabrotica barberi Smith & Lawrence, than did phenyl alkyl amines or phenyl alkyl alcohols with 1-, 3-, or 4-carbon side chains. Both sexes of northern corn rootworm were attracted to 2-phenyl-1-ethylamine in greater numbers than to 2-phenyl-1-ethanol, whereas the latter was the better attractant in the case of female western corn rootworm, Diabrotica virgifera virgifera LeConte, Differences in attractancy between the 2 compounds were attributed to differences in atomic charge; electrostatic charge was calculated to be -1.10 on the nitrogen atom in 2-phenyl-1-ethylamine but only -0.70 on the oxygen atom in 2-phenyl-1-ethanol. Northern corn rootworms responded in significantly greater numbers when the 2 compounds were blended than when a dose of either compound was increased 10-fold. This observation does not support the idea that 2-phenyl -1 -ethylamine substitutes for 2-phenyl-1-ethanol at a phenyl alkyl alcohol recognition site. In the case of cinnamvl alcohol derivatives, cinnamyl alcohol attracted the most northern corn rootworms, but cinnamaldehyde attracted the most western corn rootworms of both sexes. Male western corn rootworms responded to only cinnamaldehyde.