Plant based natural products as potential ecofriendly and safer biopesticides: A comprehensive overview of their advantages over conventional pesticides, limitations and regulatory aspects

The commercially used synthetic pesticides have been proven to be toxic not only to humans and other animals, but also to non-target plant, the surrounding organisms around the plant, and the environment. There are also increased concerns regarding the development of pest resistance towards these synthetic pesticides. As such, biopesticides, which are defined as the certain kinds of pesticides derived from natural sources such as plants, bacteria, fungi, animals and some minerals, are potential alternative pesticides and are gaining increasing attention. Biopesticides are safer and eco-friendly pesticides used for pest management. Among these, plant-based biopesticides constitute a small but important group of biopesticides. Plant based extracts and essential oils have been particularly used in the management of insects exhibiting a variety of anti-insecticidal mechanisms. Their chemical compositions are very complex and as such acquiring resistance by the pest against such biopesticide is very difficult. As far as their mechanism of action is concerned, these can act as insect repellants, insect attractants, or anti-feedants. They can also inhibit respiration or they can obstruct the host plant identification. These insecticides can inhibit oviposition and decrease adult emergence by ovicidal and larvicidal effects. Some of the essential oil based insecticides have even been commercialized for use. However, there are some limitations that restrict the widespread use of such biopesticides. These limitations include cost, difficulties in production, gentle action, and dearth of appropriate biopesticide formulations. As far as their regulations are concerned, it is still a problem in many countries further halting biopesticide use. But one thing is clear that biopesticides do have a promising future due to their eco-friendly nature and unique chemical compositions and unique mode of action.