Essential Oils as Green Pesticides: For Sustainable Agriculture

ABSTRACT The environmental problems caused by overuse of pesticides have been the matter of concern for both scientists and public in recent years. It has been estimated that about 2.5 million tons of pesticides are used on crops each year and the worldwide damage caused by pesticides reaches $100 billion annually. Natural products are an excellent alternative to synthetic pesticides as a means to reduce negative impacts to human health and the environment. The move towards green chemistry processes and the continuing need for developing new crop protection tools with novel modes of action makes discovery and commercialization of natural products as green pesticides are good alternatives to chemical pesticides. Green pesticides are eco-friendly, economic, target-specific and biodegradable. Many plant essential oils show a broad spectrum of activity against pest insects and plant pathogenic fungi ranging from insecticidal, antifeedant, repellent, oviposition deterrent, growth regulatory and antivector activities. This special regulatory status combined with the wide availability of essential oils from the flavor and fragrance industries, has made it possible to fast track commercialization of essential oil-based pesticides. Though well received by consumers for use against home and garden pests, these "green pesticides" can also prove effective in agricultural situations, particularly for organic food production. Further, while resistance development continues to be an issue for many synthetic pesticides, it is likely that resistance will develop more slowly to essential oil based pesticides owing to the complex mixtures of constituents that characterize pesticides based on plant essential oils or their constituents have demonstrated efficacy against a range of stored product pests, domestic pests, blood feeding pests etc. These features indicate that pesticides based on plant essential oils could be used in a variety of ways to control a large number of pests. Some essential oil constituents, for example, limonene, pulegone, citronellal and 1,8-cineole are active ingredients of commercially available flea shampoos, mosquito repellents and different agrochemicals