Neem as Biopesticide for a Sustainable Environment

Pesticides have both acute and chronic effects on humans and all other warm blooded living things. In pesticide applications, few of the amount used reaches the target organisms, whereas the rest mixes into the ecosystem and leads to the deterioration of the ongoing natural balance. 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. In this context, plant-derived natural products are considered valuable candidates to reverse this negative trend. Botanical pesticides are relatively safe, degradable, and are readily available sources of biopesticides. Neem is an ideal alternative candidate as a natural non-synthetic plant pesticide. The neem products have been obtained from several species of neem trees in the family Meliaceae. Array of more than 300 bioactive compounds in the neem tree makes it a unique plant with potential applications in pest and vector management. Botanical pesticides, such as neem, have limited persistence in the environment, and ultraviolet light, temperature, rainfall and other environmental factors can degrade neem. Unlike toxic synthetic insecticides, neem materials do not kill the pest, but incapacitate or neutralize it via cumulative behavioural, physiological, and cytological effects. In spite of high selectivity, neem materials affect more than 400 harmful species including insect pests, phytophagous mites, mites, and ticks affecting man and animals, parasitic protozoans, noxious molluscs, plant parasitic nematodes, pathogenic fungi, and harmful bacteria and fungi. Neem ingredients affect insects in various ways such as repellent, antifeedant, toxic, fecundity and growth regulatory effects. This review presents an overview of recent advances in research on the environmental impact of neem products and their use and effectiveness as a biopesticide.