Topical Toxicity Profiles of Some Aliphatic and Aromatic Essential Oil Components Against Insecticide-Susceptible and Resistant Strains of German Cockroach

Toxicity profiles of four aliphatic ([alpha]-pinene, cyclononanone, limonene, nerolidol), four aromatic ([beta]-thujaplicin, carvacrol, eugenol, tropolone) essential oil components (EOCs), and permethrin were investigated against three strains of German cockroach, Blattella germanica (L.). The strains include a susceptible strain (S), and two multi-resistant strains--strains D and E. Also, a synergism bioassay, using piperonyl butoxide (PBO) was conducted. The most toxic EOCs were aromatic EOCs carvacrol, eugenol, and tropolone, followed by aliphatic EOC limonene; all had L[D.sub.50] values of