Biocontrol efficacy of bay essential oil against housefly, Musca domestica (Diptera: Muscidae)

Abstract

Abstract Background The synanthropic housefly, Musca domestica, augments the transmission of several detrimental diseases like cholera and avian flu. Consequently, during the last century, many physico-chemical methods including synthetic compounds have been applied for its control. But these methods have proven to be prohibitive due to their side effects and serious issues like resistance development, environmental contamination, and detrimental effects on non-target fauna. Therefore, in view of these objectives, we investigated the effects of bay essential oil (EO) against M. domestica. Methods The attractant/repellent assays were conducted by double choice technique. Different enzyme assays evaluating the effect of LC50 concentration of the tested essential oil on larval gut were taken into consideration. To determine the composition, the tested oil was subjected to GC-MS/MS analysis. Further, the morphological alterations caused by EO treatment to third instar larvae were observed in a Nova Nano SEM machine. Data was statistically analyzed by one-way ANOVA using Tukey’s test (p < 0.001). The LC50 and LC90 values were calculated by probit analysis. Results The adulticidal bioassay revealed significant effects with LC50 concentration as 43.03 mg/dm3 against the newly emerged adult flies while in larvicidal assay mortality was dose dependent showing maximum effect at LC50 0.0629 μg/cm2. The pupicidal activity was more effective at a dose of LD50 64.09 μl/0.25 L of air which either killed the pupae or caused deformity in the emerged adults. Likewise total sugar, protein, glycogen, and lipid contents of larvae were reduced after treatment with EO when compared with the normal larvae along with some gut enzymes. The EO reduced the acetylcholinesterase activity from 0.013 U/mg protein in normal larvae to 0.0093 U/mg protein after EO treatment. The GC-MS/MS analysis of the bay EO showed the abundance of myrcene, linalool, eugenol, chavicol, and anethole along with diterpenoid, geranylgeraniol. However, the insecticidal activity of tested EO might be majorly imparted by eugenol content. The FESEM analysis showed shrinkage of integument and distortion to intersegmental regions caused by the tested compound. Conclusion The present study concludes the significant efficacy of bay EO against M. domestica which could be employed to breakdown its population below threshold levels to prevent the menace of vector-borne diseases.