Efficacy of Mentha × piperita and Mentha citrata essential oils against housefly, Musca domestica L.

The essential oils of two Mentha species: peppermint, Mentha piperita, and bergamot mint, Mentha citrata (both, Lamiales: Lamiaceae) were evaluated for its chemical composition and insecticidal activity against the housefly, Musca domestica L. (Diptera: Muscidae). The gas chromatographic–mass spectrometry (GC–MS) analysis of M. × piperita revealed menthol (26.53%), menthone (25.83%), menthyl acetate (7.35%) while M. citrata oil showed linalool acetate (26.69%) and d-linalool (24%) as major constituents. Analysis of M. × piperita oil vapour depicted increased menthone content while M. citrata oil vapour showed increase in linalool acetate and d-linalool content as compared to respective oils. Insecticidal activity of oils was assessed against larvae and pupae of housefly, through two different bioassays: contact toxicity and fumigation. For the larvicidal assay, lethal concentration, LC50 of M. × piperita oil, was 0.54 μl/cm2 (contact toxicity) and 48.4 μl/L (fumigation) while for M. citrata oil, it was 1.39 μl/cm2 (contact toxicity) and 61.9 μl/L (fumigation). Oil treated larvae showed swollen spinose areas and proliferation of spinous cells in the intersegmental region, and bleb formation at the anterior region. M. × piperita oil treated larvae showed significantly higher and acute proliferation of spinose cells and bleb formation than M. citrata oil. Pupicidal effectivity was measured in terms of percentage inhibition rate (PIR). For, M. × piperita oil, PIR was 100% for both contact toxicity and fumigation toxicity assay while M. citrata oil showed PIR of 68% and 57% for contact toxicity and fumigation assay, respectively. The present study established higher pupicidal and larvicidal efficacy of M. × piperita than M. citrata essential oil in contact toxicity as well as fumigation assay. The study demonstrates potentiality of both the Mentha oils as a control agent against housefly with M. piperita being better candidate among the two.

► Comparative study b/w M. piperita and M. citrata for their insecticidal activity.
► Composition of oil and vapour analysed by GC–MS and SPME/GC–MS, respectively.
► Insecticidal activity tested for rarely investigated housefly larvae and pupae.
► SEM of treated larvae depicts extensive damage compared to untreated larvae.