Phytochemical biopesticides: some recent developments

Synthetic pesticides in general, are highly toxic, persistent and their harmful residues contaminate crops, food commodities and pollute soils and groundwater. They adversely affect non-target organisms like pollinators, fish, birds, animals, and their excessive use results in increased resistance in pests. Phytochemical biopesticides on the other hand are less toxic, least persistent, environment friendly and safe to humans and non target organisms. Several phytochemical biopesticides like azadirachtin, nicotine, pyrethrins, rotenone, veratrum, annonins, rocaglamides, isobutylamides etc. have been successfully commercilalized in the past. In this review pesticidal products based on Madhuca indica (Mahua), Sapindus mukorossi (soapnut), Curcuma longa (turmeric), Pongamia glabra (karanja), Eupatorium adenophorum (Crofton weed), Tagetes erecta (marigold), Rheum emodi (Himalayan Rhubarb) and essential oil bearing plants have been discussed. Natural insecticide synergists derived from Anethum sowa and their semisynthetic derivatives have been used to prolong efficacy and counter resistance in insect pests.