Potential of essential oils to prevent fly strike and their effects on the longevity of adult Lucilia sericata

Authors: KHATER, HANEM - Benha University; Geden, Christopher - Chris

Submitted to: Journal of Vector Ecology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/12/2018
Publication Date: 11/8/2018
Citation: Khater, H., Geden, C.J. 2018. Potential of essential oils to prevent fly strike and their effects on the longevity of adult Lucilia sericata. Journal of Vector Ecology. 43(2):261-270. https://doi.org/10.1111/jvec.12310.
DOI: https://doi.org/10.1111/jvec.12310

Interpretive Summary: Lucilia sericata, or green bottle fly, is a common species of blow fly in most parts of the world. Although it usually lays its eggs on carrion, in Europe and Australia L. sericata is called the sheep blow fly because the flies also lay eggs in the wool of sheep. When this occurs, the fly larvae feed on the skin of the animal and can cause massive lesions and secondary infection. This condition, known as “fly strike”, causes vast economic damage and affects 1 million sheep each year in the UK alone. Most fly control efforts have focused on the use of traps against adults and dipping the sheep in insecticides to kill the larvae. In this study, conducted by scientists in Egypt and at USDA’s Center for Medical, Agricultural, and Veterinary Entomology, the potential of essential oils (EO) from plants was evaluated against adult flies in an attempt to repel and kill adult flies before they have a chance to lay eggs on the animals. Essential oil of vetiver (a grass native to India) and a blend that included it were nearly 100% effective in preventing gravid flies from laying eggs. Young flies were also highly repelled by blends that included vetiver. EOs of vetiver, cinnamon and lavender were 12-18 times more toxic to adult flies than sunflower oil. Adult flies that were exposed to vetiver-treated liver lived only about 1/6 as long as untreated controls. The results could be used to develop products that would offer a low-cost, environmentally friendly alternative or compliment to current control methods.

Technical Abstract: Lucilia sericata is a primary facultative ectoparasite of warm-blooded vertebrates. It is controlled by traps or insecticides, but both have drawbacks and alternative ways of control are urgently needed. Essential oils (EOs) of vetiver (Chrysopogon zizanioides), cinnamon (Cinnamomum zeylanicum), and lavender (Lavandula angustifolia) and their blends (OBs); OB1 (2 ml of each EO plus 4 ml of sunflower oil as a carrier) and OB2 (2 ml of each EO) were tested. Oils were tested at 5% for deterrence assays, and a dose response assay 0.01-0.6%, was conducted to determine forced-contact toxicity. We evaluated the efficacy of oils as oviposition deterrents, repellents/attractants, and their effects on mortality and longevity of adult L. sericata for the first time. Our data indicated that 0.2% EOs killed all flies by 5 min post-treatment and that vetiver oil greatly deterred flies from the oviposition medium and reduced adult longevity. Sunflower oil repelled all flies form oviposition and greatly reduced the lifespan of treated adults. The blend of the four oils (OB1) had the greatest repellent effect on the flies. EOs have insecticidal, repellent, and oviposition-deterrent activities against L. sericata that could be used for suppression of blowfly populations.