Pustaka Ilmiah Universitas Padjadjaran

Abstrak

A Preliminary Study On The Fumigant Toxicity Of Essential Oils To Eggs And Larvae Of Queensland Fruit Fly Bactrocera Tryoni

Essential oils are often used in daily lives of human food as flavours, fragrances, in alternative medicine, as antiseptics and mosquito repellents. The aim of this study was to evaluate the fumigant toxicity of eight essential oils (Eucalyptus citriodora, Eucalyptus staigeriana, Eucalyptus radiata, Eucalyptus dives, Leptospermum petersonii, Mentha piperita, Melaleuca teretifolia and Citrus limon) against eggs and larvae of Queensland fruit fly Bactrocera tryoni (Froggatt). Forty eggs were exposed to each essential oil at a dose of 100 µl/L air for 6 and 24 h in a fumigation chamber. After treatment, the treated and control eggs were transferred to petri dishes containing carrot-based diet. The fumigant toxicity of the essential oils was tested also against the first, second and third instars. Twenty larvae of each instar were placed in carrot-based diet and exposed to each essential oil at a dose of 100 µl/L air for 24 h. The results of a 24-h exposure test showed that essential oil of M. piperita had strong fumigant effect on eggs, reducing the hatching to 3.8% in treated eggs compared to untreated 91.9%. However, the same M. piperita essential oil showed low fumigant effect against the larval stages. Essential oil of E. dives showed low fumigant effect against eggs but it showed strong fumigant effect on the first and second instars. From 20 larvae exposed to E. dives essential oil, of the first instars only 10% reached the pupal stage and of the second instars only 3.8% pupated compared with 95.0% and 98.8% in each control. None of the tested essential oils showed fumigant effects on third instars. Results indicate that E. dives and M. piperita essential oils merit further investigation for their potential as fumigants against early instars and eggs of Queensland fruit fly.