Halogenated sesquiterpenes pacifenol and pacifenol derivatives on the aphid Schizaphis graminum

Pacifenol, a halogenated sesquiterpene was isolated from Laurencia claviformis. The effects of pacifenol and two derivatives on survival and feeding behaviour of the aphid Schizaphis graminum were studied. Toxicity of pacifenol was lower than the other compounds, and the dibromo derivative was more toxic than pacifidiene. At concentrations higher than 250 and 750 ppm, respectively, both compounds acted as antifeedants on aphids. © 1993