Insecticidal Activity of Monoterpenoids to Western Corn Rootworm (Coleoptera: Chrysomelidae), Twospotted Spider Mite (Acari: Tetranychidae), and House Fly (Diptera: Muscidae)

Abstract

Acute toxicities of 34 naturally occurring monoterpenoids were evaluated against 3 important arthropod pest species; the larva of the western corn rootworm, Diabrotica virgifera virgifera LeConte; the adult of the twospotted spider mite. Tetranychus urticae Koch; and the adult house fly. Musca domestica L. Potential larvicidal or acaricidal activities of each monoterpenoid were determined by topical application, leaf-dip method, soil bioassay, and greenhouse pot tests. Phytotoxicity was also tested on a corn plant. Citronellic acid and thymol were the most topically toxic against the house fly, and citronellol and thujone were the most effective on the western corn rootworm. Most of the monoterpenoids were lethal to the twospotted spider mite at high concentrations; carvomenthenol and terpinen-4-ol were especially effective. A wide range of monoterpenoids showed some larvicidal activity against the western corn rootworm in the soil bioassay. Perillaldehyde, the most toxic (LC50 = 3 micrograms/g) in soil, was only 1/3 as toxic as carbofuran, a commercial soil insecticide (LC50 = 1 microgram/g). Selected monoterpenoids also effectively protected corn roots from attack by the western corn rootworm larvae under greenhouse conditions. alpha-Terpineol was the best monoterpenoid in the greenhouse pot test. The acute toxicity of monoterpenoids was low relative to conventional insecticides. Some monoterpenoids were phytotoxic to corn roots and leaves. l-Carvone was the most phytotoxic, whereas pulegone was the safest. The results with thymyl ethyl ether, one of the synthetic derivatives of thymol, showed a potential of derivatization to reduce monoterpenoid phytotoxicity.

Toxicity of Seven Monoterpenoids to Tracheal Mites (Acari: Tarsonemidae) and Their Honey Bee (Hymenoptera: Apidae) Hosts When Applied as Fumigants

“…Cages were and Muller 1976, Andrews et al 1980, Watanabe et al 1990, and Ikawa et al 1992. Lee et al (1997) and Rice and Coats (1994) are currently investigating structure-activity relationships for monoterpenoids applied to various arthropods.…”

“…Furthermore, at concentrations below the calculated LCsos, all 4 compounds reduced oviposition, and 3 of the compounds increased movement. Lee et al (1997) reported that most of the 30 monoterpenoids they tested for activity against the twospotted spider mite, Tetranychus urlicae Koch, exhibited some degree of acaricidal activity, especially the alcohols, phertols, and ketones. Larson and Berry (1984) examined T. urlicae fecundity and development on peppermint, Mentha piperita, leaves that differed in monoterpene content, but were unable to correlate monoterpene content of leaves with either fecundity or development.…”

Cardiovascular effects of monoterpenes: a review

“…Several monoterpenes are widely used in the agriculture, cosmetic, and food industries, and as a general antiseptic in medical practice (Aeschbach et al, 1994;Lee et al, 1997;Manou et al, 1998). Most of the aroma from citrus fruit oil, cherries, and mint is due to the high content of monoterpenes, but they have no nutritional value because they are exclusively vegetable (Serrano et al,2006).…”

Quantitative Structure-Activity Relationships (QSARs) of Monoterpenoids at an Expressed American Cockroach Octopamine Receptor

“…The complexity of the terpenoid mixture is enhanced by the presence of various functional groups, stereochemistry, and carbon skeletal structures (1). The toxicity of essentials oils and their terpenoid constituents to insects has been the focus of several studies (2)(3)(4). While these terpenoids have been shown to be toxic to insects, their precise mechanism of how they exert this toxic action is not fully understood.…”