Toxicity of Citrus Oils to Several Stored-Product Insects: Laboratory Evaluation2

Abstract

Oils were extracted from the peels of 8 different fruits and tested for toxicity to serveral species of stored-product insects. Topical applications showed that lyophilized oils from lemon, grapefruit, lime, kumquat, and tangerine were highly toxic to the cowpea weevil, Callosobruchus maculatus (F.), and that all 8 oils were moderately toxic to the rice weevil, Sitophilus oryzae (L.). TLC analyses and topical applications to the insects showed that the active component of the lemon peel was not a residue of the insecticides and acaricides generally used as prehavest treatments, or of the fungicides used as postharvest treatments.