EVALUATE THE EFFECTIVENESS OF OLEIC ACID AND LINOLEIC ACID IN CONTROLLING THE TROGODERMA GRANARIUM EVERTS (COLEOPTERA: DERMESTIDAE)

Abstract

This study aimed to evaluate the effectiveness and efficiency of the two fatty acids, Oleic acid, and Linoleic acid, by contact method as a natural and safe alternative to chemical pesticides in controlling the motile stages (adults, larvae) of grain beetle Trogoderma granarium Everts. This laboratory study included four concentrations (50, 100, 150, 200) ppm with three exposure times (8, 16, 24) h. The results showed that the treatment of insect adults with oleic and linoleic acid gave the highest killing rates at a rate of 96.66% and 93.33%, respectively, while the killing rates for larvae after treatment with the two acids were 75.55% and 74.44%, respectively, at a concentration of 200 ppm and a 24-h exposure period of both transactions. The results showed, in general, significant effects of the concentrations and durations of exposure and the interaction between both acids on insect-killing rates. It was also noted that oleic acid was superior to linoleic acid in causing killing rates in the two cycles at most concentrations and exposure times used for its ability to penetrate the cuticle layer in insects from their flexible regions and respiratory openings when they moved on it and causing many deformations of their tissues because of its double bonds that make it occupy a larger cross-section. It increases kinetic freedom in the membrane of the target organism as soon as it enters its body and induces cellular toxicity, causing its death.