Toxicity, behavioural and biochemical effect of Piper betle L. essential oil and its constituents against housefly, Musca domestica L.

Housefly, Musca domestica L. is a pest of public health importance and is responsible for spreading diseases like typhoid, diarrhoea, plague etc. Indiscriminate reliance on synthetic insecticides has led to development of insecticide resistance and ill effect to humans and nontarget animals. This demands an alternative and safer pest control option. This study evaluates the biological effect of Piper betle L essential oil and its constituent eugenol, eugenol acetate, and beta-caryophyllene on the housefly. The major components present in P. betel EO were safrole (44.25%), eugenol (5.16%), beta-caryophyllene (5.98%), beta -selinene (5.93%), alpha-selinene (5.27%) and eugenol acetate (9.77%). Eugenol caused 4.5fold higher ovicidal activity (EC50 86.99 mu g/ml) than P. betle EO (EC50 390.37 mu g/ml). Eugenol caused fumigant toxicity to adults (LC50 88.38 mg/dm(3)). On contact toxicity by topical application, eugenol acetate, eugenol and beta-caryophyllene caused higher mortality to larval and adult stages than EO. FESEM (Field Emission Scanning Electron Microscope) images reveal that exposure to P. betle EO causes the shrinkage of the larval cuticle. Both EO and eugenol induced the detoxifying enzymes Carboxyl esterase (Car E) and Glutathione S - transferases (GST) in larvae and adults. EO and eugenol at 0.2% caused effective repellence and oviposition deterrence to M. domestica adults and this merits their use as alternative strategy to manage M. domestica