Essential oils as green pesticides: An overview

Essential oils (EOs) obtained from different parts of plants consist of diverse chemical constituents. Most of the essential oils are rich in monoterpenes, sesquiterpenes and phenylpropenes. The diversity of chemical constituents imparts several biological activities such as insecticidal, repellent, attractant, antifeedant, oviposition deterrent, disruption in growth regulation, fungicidal and antiviral to these essential oils. Traditionally, EOs are being utilised for management of insect pests both in field crops and storage. Mostly these essential oils are found to affect insects by inhibiting several enzymes such as acetylcholine esterages, Glutathion S-transferages and also octopaminergic nervous system. They do not show toxicity against the mammals and fishes, due to absence of target site in these organisms. A few essential oils are exempted from pesticide registration and are being used as seasoning agents in food and beverage products. Moreover, these EOs can be a potential “green pesticide” against agricultural pests and support to the organic food production. The main purpose of this review is to emphasize on biological activities of EOs. This comprehensive and critical review will be helpful for chemists to develop more candidates based on these moieties and also for plant protectionists to identify promising EOs as per the need.