Larvicidal Activity of Eucalyptus globulus (Myrtaceae) and Origanum majorana (Lamiaceae) Essential Oils against the Sand Fly Phlebotomus papatasi (Diptera: Psychodidae)

Abstract

The essential oils of Eucalyptus globulus and Origanum majorana were evaluated for their larvicidal activity against third instar larvae of the sand fly Phlebotomus papatasi. E. globulus oil showed lethal concentration, LC50, of 677 g/ml whereas the LC50 value for O. majorana was 91 g/ml. Larvae treated with both oils showed surface shrinkage, spinous cells proliferation, bleb formation, abdominal distortion of microtrichia and partial or complete closure of spiracles in scanning electron microscopy (SEM). At 48 h post treatment, both oils induced severe structural changes in the gut cells, brush border and degeneration of the peritrophic matrix. Origanum majorana essential oil was more potent than E. globulus against third instar larvae of P. papatasi based on its lower LC50 value. Taking all data into account, essential oils of E. glolbulus and O. majorana could be considered as a viable option for the development of eco-friendly house hold product against sand flies.