~ 13 ~ International Journal of Mosquito Research 2021; 8(6): 13-19 ISSN: 2348-5906 CODEN: IJMRK2 IJMR 2021; 8(6): 13-19 © 2021 IJMR www.dipterajournal.com Received: 02-09-2021 Accepted: 08-10-2021 Anjali Rawani 1) Department of Zoology, University of Gour Banga, Malda, West Bengal, India 2) Mosquito, Microbiology and Nanotechnology Research Units, Parasitology Laboratory, Department of Zoology, The University of Burdwan, Purba Bardhaman, West Bengal, India Anupam Ghosh 1 ) Department of Zoology, Bankura Christian College, Bankura, West Bengal, India 2) Mosquito, Microbiology and Nanotechnology Research Units, Parasitology Laboratory, Department of Zoology, The University of Burdwan, Purba Bardhaman, West Bengal, India Goutam Chandra Mosquito, Microbiology and Nanotechnology Research Units, Parasitology Laboratory, Department of Zoology, The University of Burdwan, Purba Bardhaman, West Bengal, India Corresponding Author: Goutam Chandra Mosquito, Microbiology and Nanotechnology Research Units, Parasitology Laboratory, Department of Zoology, The University of Burdwan, Purba Bardhaman, West Bengal, India Evaluation of mosquito larvicidal activities of stem, root and flower of Solanum nigrum L. against filarial vector Culex quinquefasciatus Say Anjali Rawani, Anupam Ghosh and Goutam Chandra Abstract Plant-based insecticides are eco-friendly, target-specific, less harmful to non-targets, biodegradable, and less prone to developing resistance. The present study was carried out to evaluate the mosquito larvicidal activity of crude and ethyl acetate solvent extracts of the stem, root, and flower of Solanum nigrum L. against immatures of Culex quinquefasciatus Say. Early third instar larvae of Cx. quinquefasciatus were exposed to 1, 1.5, 2, 2.5 and 3% of crude and 30, 50, 80, 100, and 120 ppm concentrations of ethyl acetate extracts of the stem, root, and flower. The highest mortality was observed at 3% crude and 120 ppm ethyl acetate extracts after 72 hours of exposure in all the plant parts. The lowest LC50 and LC90 values of crude and ethyl acetate extracts were observed to be 0.98% and 2.23%, and 30.38 ppm and 166.99 ppm respectively in the stem of S. nigrum. Apparent dose-dependent mortality was observed as a positive correlation between mortality (Y) and concentration (X) with a regression coefficient value close to one in each case. The IR and GC-MS analyses were carried out to find out the active ingredient. Chemical characterization revealed the presence of steroidal alkaloids in the stem as a primary active ingredient, which might be responsible for larval toxicity. The active ingredient of the stem did not cause any abnormality to non-target organisms. As a whole, different plant parts of S. nigrum showed varied larval mortality, so selectively, those can be employed to prepare cost-effective insecticides to control the mosquito population. Keywords: Solanum nigrum, stem, root, flower, Culex quinquefasciatus, larvicidal activity, GCMS analysis 1. Introduction In terms of public health concerns, mosquitoes are the most vital solitary group of vectors that transmit several deadly diseases like Malaria, Filariasis, Dengue, Japanese encephalitis in various tropical and subtropical countries. Worldwide in 91 countries, 216 million people are suffering from malaria alone [1] . While 859 million people in 50 countries worldwide remain threatened by lymphatic filariasis, among them, at least 25 million men were affected with hydrocele and over 15 million people with lymphoedema. However, 36 million people remain with these chronic disease manifestations [2] . Filariasis, a mosquito-borne disease, is principally caused by nematode Wuchereria bancrofti and transmitted by the female Culex quinquefasciatus mosquito. In India, the microfilaria carriers are estimated to be about 31 million people and suffer from filarial symptoms of over 23 million people [3] . Besides transmitting various diseases, mosquito bites may cause an allergic reaction such as local skin allergy and systemic sensitivity [4] . New control strategies have targeted to reduce the man-vector contact, primarily by reducing mosquito breeding sites and biting activity by using a blend of chemical-biological control methods to reduce the population of mosquitoes [5] . Various pesticides (chemical formulations) have been a matter of choice to control or eradicate mosquito populations. Although they are highly efficacious and show rapid action against the target species, these chemical pesticides are facing the threat of developing resistance [6] . The residues of these pesticides cause environmental pollution and mortality of other non-target organisms. Plant secondary metabolites [7-9] are considered a more potent option than chemical insecticides as they are rich in bioactive compounds that are environment-friendly, target-specific, readily available, cost- effective and biodegradable [10] . Insecticides of plant origin are not only responsible for larval