|Chang, Chiou Ling|
|Ilkyu, Cho - UNIVERSITY OF HAWAII|
|Qing, X. Li - UNIVERSITY OF HAWAII|
Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: October 13, 2008
Publication Date: March 2, 2009
Citation: Chang, C.L., Ilkyu, C., Qing, X. 2009. Insecticidal Activity of Basil Oil, trans-Anethole, Estragole, and Linalool to Adults of Ceratitis capitata, Bactrocera dorsalis, and B. cucurbitae. Journal of Economic Entomology. 102: 203-209. Interpretive Summary: Basil has the innate ability to discourage herbivory when insects are not abundant. It can be used as an alternative to chemical pest control. Basil oil, extracted via steam distillation from the leaves and other parts of the plants, is used as an additive to flavor foods, as dental and oral products, as fragrance, and in traditional rituals and medicines. Basil oil contains bioactive constituents that are insecticidal, repellent, nematicidal, fungistatic or antimicrobial. These properties can frequently be attributed to predominant essential oil constituents such as methyl chavicol (estragole), methyl eugenol, linalool, camphor, and methyl cinnamate. Pest tephritid fruit flies directly damage crops and are quarantine species. Medfly, Ceratitis capitata (Wiedemann), Oriental fruit fly, Bactrocera dorsalis (Hendel), and melon fly, B. cucurbitae (Cocquillett) are currently three species of tephritid fruit flies of economic significance in Hawaii and worldwide. Control and detection of these fly species have primarily relied on the use of food baits, parapheromones (i.e., male attractants) and their combinations with insecticides. Medlure, methyl eugenol and cuelure are known to be male attractants to C. capitata, B. dorsalis, and B. cucurbitae, respectively. The objectives of this study were to investigate the insecticidal activity of basil oil and its major constituents, identify the lethal doses and to investigate the compatibility with methyl eugenol or cuelure for potential applications to “attract and kill” the fruit flies.
Technical Abstract: Pest tephritid fruit flies, Ceratitis capitata (Wiedemann), Bactrocera dorsalis (Hendel), and B. cucurbitae (Cocquillett) are among the species of economic significance. Their management has primarily relied on the use of food baits, male attractants and their combinations with insecticides. Basil oil (Ocimum basilicum Linn) and its three major active constituents were tested on the three fly species in the present study. Basil oil, linalool, trans-anethole, and estragole acted fast and showed a steep dose-response relationship. The time for 90% mortality of the three fruit fly species under 10% of these test chemicals were 8-38 min. When linalool was mixed with cuelure, its potency to the three fly species decreased as the concentration of cuelure increased. This was due to linalool hydrolysis catalyzed by acetic acid generated from cuelure degradation. When methyl eugenol was mixed with basil oil, trans-anethole, estragole or linalool, it did not affect the mortality of B. dorsalis from both basil oil and linalool, but did significantly decrease the toxicity of trans-anethole and estragole. Methyl eugenol might act at a site similar to that of trans-anethole and estragole if an action site exists. Methyl eugenol may also play a physiological role on the toxicity reduction.