Progress on Azadirachta indica Based Biopesticides in Replacing Synthetic Toxic Pesticides

Abstract

Over the years, extensive use of commercially available synthetic pesticides against phytophagous insects has led to their bioaccumulation in the environment causing increased resistance and reduction in soil biodiversity. Further, 90% of the applied pesticides enter the various environmental resources as a result of run-off, exposing the farmers as well as consumers of the agricultural produce to severe health issues. Therefore, growing attention has been given toward the development of alternate environmentally friendly pesticides/insecticides that would aid an efficient pest management system and also prevent chronic exposures leading to diseases. One such strategy is, the use of neem plant's (Binomial name: Azadirachta indica) active ingredients which exhibit agro-medicinal properties conferring insecticidal as well as immunomodulatory and anti-cancer properties. The most prominent constituent of neem is azadirachtin, which has been established as a pivotal insecticidal ingredient. It acts as an antifeedant, repellent, and repugnant agent and induces sterility in insects by preventing oviposition and interrupting sperm production in males. This review discusses, key neem pesticidal components, their active functional ingredients along with recent strategies on employing nanocarriers, to provide controlled release of the active ingredients and to improve their stability and sustainability.

Azadirachtin effects on mating success, gametic abnormalities and progeny survival in Drosophila melanogaster (Diptera)

“…63 Azadirachtin was found to inhibit oogenesis and spermiogenesis in several species. 9,64 Our observation of decreases in the number of oocytes and in the size of the basal oocyte can be explained by the severe degeneration of follicle cells, fragmentation in the germinal vesicle 9 and alterations of mitochondria caused by this insecticide. 65 Azadirachtin also alters or prevents the formation of new actin cytoskeleton resulting in the disruption of cell division and nutients transport.…”

“…This disruption may affect the process of dumping the cytoplasmic contents of nurse cells to the ovocyte and impact vitellogenesis . Furthemore, azadirachtin interferes with ecdysteroid synthesis and vitellogenin synthesis (and/or its uptake), affecting oocyte development via JH as noted in D. melanogaster . The impact of azadirachtin on D. melanogaster adult females, as highlighted here, thus may be related to the fact that JH stimulates vitellogenesis for the developing oocytes and, together with 20E and insulin‐signalling pathways, controls the nutrient‐sensitive checkpoint in oogenesis .…”

Inhibitory effects of components from root exudates of Welsh onion against root knot nematodes

“…Plants have developed three main mechanisms of resistance against RKNs, which are prevention of interaction between RKNs and the roots [32], interference with normal RKN development, and restriction of RKN growth [16]. We believe that Welsh onion, grown as a companion plant, may decrease RKN-induced damage to cucumber through activity of the root exudates by restricting normal RKN development and retarding RKN growth.…”

“…These extracts penetrate the nematode egg mass matrix and significantly restrict egg hatching as well as kill J2 (i.e., the second-stage juveniles) and enhance plant growth [15]. Moreover, extracts from neem [16], marigold [17], and mint [18] are directly lethal to nematodes.…”

Acute toxicity evaluation of mixture of neem (Azadirachta indica) and moringa (Moringa oleifera) seed oils in rats

“…The remaining triterpenoids including nimbin, salannin, and their derivatives contribute little to the efficacy (Isman, 2006). Interestingly, neem oil is non-toxic to mammals, birds and fishes and exhibit fewer chances of resistance due to its multiple mode of actions on insect (Chaudhary et al, 2017).…”