ABSTRACT
ABSTRACT: The management of house fly, Musca domestica has become immensely important to prevent epidemics of many detrimental diseases. In view of this objective, the present study demonstrates the efficacy of lemongrass (LG) and tea tree essential oils (TTEOs) against M. domestica. The TTEO proved to be more lethal against larvae and adults of M. domestica depicting an LC50 at 14.88 mg/ dm3 which was 17.19 mg/ dm3 for LGEO. In contrast, pupicidal effect of LGEO was much higher (LD50, 14.49 µl/0.25L) as compared to TTEO. The LGEO drastically reduced the total body sugar, glycogen and protein contents by 3.29, 2.95 and 7.56 fold, respectively, contrasting with high influence of TTEO on lipid content of the late 3rd instar larvae. A considerable reduction in gut enzymes secretion was observed due to treatment of EOs thereby altering gut physiology of the insect. Moreover, significant inhibition of acetylcholine esterase (AchE) was also observed with LGEO at LC50 concentration (5.33 mg/ml) inhibiting insect neurotransmission. The gas chromatography-mass spectrometric (GC-MS) analysis of the LGEO showed 12 major compounds dominated by Citral whereas TTEO contained only 5 major compounds. Further analysis by field emission scanning electron microscopy (FESEM) revealed distortion and shrinkage of larval bodies caused by the treatment of EOs. These overall observations brand LG and TT-EOs as potential organic-insecticides against M. domestica. SUPPLEMENTARY INFORMATION: The online version of this article (10.1007/s40011-020-01220-z) contains supplementary material, which is available to authorized users.
ABSTRACT
Due to the global health problems associated with mosquito-borne diseases, over two million people primarily in the tropical countries are at risk. The widely and commonly used chemical method though effective, has some major disadvantages making insect control practically difficult. In view of the above, it is unavoidable to search for new molecules, which are eco-friendly, cheaper, and safer. The present study deals with evaluation of bioactive potential of two commonly occurring plants against mosquitoes presenting an alternative to the conventional chemical methods. Essential oils extracted by steam distillation from rhizome of Zingiber officinalis and leaf and stem of Achyranthes aspera were evaluated for larvicidal, attractant/repellent, and oviposition attractant/deterrent activity against two mosquito species viz. Aedes aegypti and Culex quinquefasciatus. The highest larvicidal activity, i.e., LC(50) = 154 ppm and LC(50) = 197 ppm for A. aegypti and C. quinquefasciatus, respectively was shown by Z. officinalis. This oil also offers 5-h protection at the concentration of 0.5 mg/cm² from both mosquito species. The highest oviposition deterrence activity was exhibited by A. aspera stem oil, i.e., 100% and 85.71%, in case of A. aegypti and C. quinquefasciatus, respectively, at the concentration of 0.1%. These results reveal that both these oils have control potential against A. aegypti and C. quinquefasciatus.
