Acta Tropica 240 (2023) 106858 Available online 5 February 2023 0001-706X/© 2023 Elsevier B.V. All rights reserved. Neem-based products as potential eco-friendly mosquito control agents over conventional eco-toxic chemical pesticides-A review Soumendranath Chatterjee a, * , Souvik Bag a , Debraj Biswal b , Dipanwita Sarkar Paria c , Raktima Bandyopadhyay d , Basanta Sarkar a , Abhijit Mandal a , Tushar Kanti Dangar e a Parasitology and Microbiology Research Laboratory, Department of Zoology, The University of Burdwan, Burdwan 713104, West Bengal, India b Department of Zoology, Government General Degree College at Mangalkote, Burdwan 713132, West Bengal, India c Department of Zoology, Chandernagore College, Hooghly 712136, West Bengal, India d Department of Nutrition, AKPC Mahavidyalaya, Hooghly 712611, West Bengal, India e Microbiology Laboratory, Division of Crop Production, National Rice Research Institute, Cuttack 753006, Odisha, India A R T I C L E INFO Keywords: Arbovirus vector Azadirachta indica Larvicide Mosquito repellent Neem oil formulations Eco-friendly mosquito control ABSTRACT Mosquitoes cause serious health hazards for millions of people across the globe by acting as vectors of deadly communicable diseases like malaria, flariasis, dengue and yellow fever. Use of conventional chemical in- secticides to control mosquito vectors has led to the development of biological resistance in them along with adverse environmental consequences. In this light, the recent years have witnessed enormous efforts of re- searchers to develop eco-friendly and cost-effective alternatives with special emphasis on plant-derived mos- quitocidal compounds. Neem oil, derived from neem seeds (Azadirachta indica A. Juss, Meliaceae), has been proved to be an excellent candidate against a wide range of vectors of medical and veterinary importance including mosquitoes. It is environment-friendly, and target-specifc at the same time. The active ingredients of neem oil include limonoids like azadirachtin A, nimbin, salannin and numerous other substances that are still waiting to be discovered. Of these, azadirachtin has been shown to be very effective and is mainly responsible for its toxic effects. The quality of the neem oil depends on its azadirachtin content which, in turn, depends on its manufacturing process. Neem oil can be used directly or as nanoemulsions or nanoparticles or even in the form of effervescent tablets. When added to natural breeding habitat waters they exert their mosquitocidal effects by acting as ovicides, larvicides, pupicides and/or oviposition repellents. The effects are generated by impairing the physiological pathways of the immature stages of mosquitoes or directly by causing physical deformities that impede their development. Neem oil when used directly has certain disadvantages mainly related to its disin- tegration under atmospheric conditions rendering it ineffective. However, many of its formulations have been reported to remain stable under environmental conditions retaining its effciency for a long time. Similarly, neem seed cake has also been found to be effective against the mosquito vectors. The greatest advantage is that the target species do not develop resistance against neem-based products mainly because of the innumerable number of chemicals present in neem and their combinations. This makes neem-based products highly potential yet unexplored candidates of mosquito control agents. The current review helps to elucidate the roles of neem oil and its various derivatives on mosquito vectors of public health concern. 1. Introduction Mosquitoes (Diptera: Culicidae) transmit deadly human diseases like malaria, dengue haemorrhagic fever, flariasis, Japanese encephalitis and yellow fever, making them one of the leading causes of human mortality (Mittal, 2003). According to records, mosquito-borne illnesses cause death of about one million people annually (World Health Organization, 2012). Under this situation, vector control seems to be the most effective strategy to reduce the number of deaths. The mainstays of mosquito vector control include the use of larvicidal chemicals and application of repellents or insecticide-treated bed nets to keep away the adults. For instance, organophosphates and insect growth regulators are primarily used to target the Culicid (Family: Culicidae) larvae. However, widespread use of chemical pesticides has been associated with the * Corresponding author. E-mail address: soumen.microbiology@gmail.com (S. Chatterjee). Contents lists available at ScienceDirect Acta Tropica journal homepage: www.elsevier.com/locate/actatropica https://doi.org/10.1016/j.actatropica.2023.106858 Received 1 December 2022; Received in revised form 2 February 2023; Accepted 3 February 2023