Biocontrol efficacy of some essential oils as larvicides and inhibitors of the emergence of adult Musca domestica

Background: Musca houseflies are a global pest that increases the spread of a number of harmful illnesses in humans and is difficult to control. Objective: Over the past century, synthetic insecticides used to manage this pest. These methods have proven to be harmful to the environment and expensive. This study evaluated the potential of Rosmarinus officinalis, Piper nigrum, Cinnamomum verum, Cyperus rotundus, Melaleuca alternifolia, and Aloe vera essential oils against 3rd stage house fly larvae. Material and Methods: Bioassays were performed to determine the effects of EOs on larvae using ingestion and contact-treated filter paper. The larvae cups were treated with 0.5, 1.0, 2.5, 5.0, and 10% EOs. To determine the composition, the tested oils were subjected to GC-MS analysis. Data using probit analyses to calculate the lethal concentration (LC) values and a one-way analysis of variance (ANOVA) (Post Hoc/Turkey's HSD test). Results: We tested the essential oils (Eos) of Rosmarinus officinalis, Piper nigrum, Cinnamomum verum, Cyperus rotundus, Melaleuca alternifolia, and Aloe vera for their toxic and inhibitory effects against larval house flies of Musca domestica L. (Diptera: Muscidae). All the oils had high to moderate toxicity against house fly larvae. Third-instar larvae died with 100% mortality in tests using treated media and between 91.11 and 100% in tests using contact-treated filter paper. R. officinalis and C. verum were the best Eos for killing housefly larvae, delaying larval and pupae development, and increasing the inhibition rate (100%). Melaleuca alternifolia was less effective (73.3% and 91.11 mortality) than the others in treated media and contact bioassays. The GC-MS tests showed that the R. officinalis oil had more monoterpenes (α-Pinene and eucalyptol), while the C. verum oil had more flavonoid compounds (cinnamonaldehyde). Conclusion: Rosmarinus officinalis and Cinnamomum verum Eos can be effective insecticides against house fly larvae.