Submitted to: International Conference on Urban Pests
Publication Type: Proceedings
Publication Acceptance Date: 7/20/2003
Publication Date: 5/20/2005
Citation: Osbrink, W.L., Lax, A.R., Cantrell, C.L. 2005. Comparison of natural and conventional insecticides against formosan termites (isoptera: rhinotermitidae). International Conference on Urban Pests p. 213-223.
Interpretive Summary: The Formosan subterranean termite (Coptotermes formosanus Shiraki) is the most destructive termite where it occurs. Chemical control strategies have failed to protect structures from this termite, resulting in many millions of dollars of structural damage. The need to discover new chemistries which improve the effectiveness of termite control agents and are also friendly with regards to environmental and health issue is urgent. The best five compounds discovered after the evaluation of hundreds of natural compounds for activity against the Formosan termites are tested side by side with 16 of the most successful synthetic insecticides used against termites. This allows for a comparison of the relative activities of the best natural compounds with the bench mark set by the synthetic insecticides. Though the natural compounds tended to be less active than the existing synthetic insecticides, discovery of the most active natural compounds also provides a starting point for chemical modification of these natural products to improve their activity against termites. Subterranean termites cost Americans more than a billion dollars a year over most of the continental United States and Hawaii. Our discovery that some of the naturally produced chemicals have substantial activity against the Formosan termites provides a starting point for chemical modification of these natural products to improve their activity against termites.
Technical Abstract: Five natural and 16 synthetic compounds were evaluated for termiticidal activity against the Formosan subterranean termite, Coptotermes formosanus Shiraki (Isoptera: Rhinotermitidae). The naphthoquinones menadione, plumbagin, and juglone, and the benzoquinones thymoquinone, and coenzyme Q1 killed all the termites at their higher rates. However, these naturally derived compounds were generally less active when compared with the conventional insecticides: permethrin, cis-permethrin, trans-permethrin, cypermethrin, a-cypermethrin, B-cypermethrin, bifenthrin, fenvalerate, cyfluthrin, B-cyfluthrin, deltamethrin, tralomethrin, chlorpyrifos, propoxur, imidacloprid, and boric acid. Evaluated natural products displayed minimal termiticidal activity at < 0.5% wt:wt. All of the synthetic insecticides caused 100% mortality at < 0.05% wt:wt except boric acid.