Botanical Pesticides: Environmental Impact uri icon

abstract

  • The insecticidal properties of natural plant products have been known sinceancient times. It is estimated that over 2,000plant species possess biologicalactivity against insects, and the principal chemicals that impart such activityinclude alkaloids, terpenoids, acetogenins and flavonoids. Among the variousplant products used as insecticides, nicotine from Nicotiana tabacum andpyrithrins from Chrysanthemum cinerariaefolium are the most prominent.Pesticide formulations developed from neem (Azadirachta indica), karanja(Pongamia glabra), and custard apple (Annona squamosa) have also shownpromise for pest management. Despite voluminous information on theusefulness of these products as pest control chemicals, their exploitation inpractical agriculture is limited due to low toxicity, latent period of action,short shelf-life, rapid degradation, and limited spectrum of activity. However,there is a general prevailing belief that natural plant products are easilybiodegradable, and thus, are considered safer as compared to syntheticpesticides. However, there is little information on their metabolism in soil,water and plants. Although considered safe to nontarget natural enemies ofcrop pests, plant products might still have the same toxic and anti-moltingeffects on these organisms as on the target arthropods, in addition to theirindirect effects through sub-optimal prey. There is very little information onthe effects of these products on the activity of microbes in the soil, and onthe aquatic organisms. Large-scale use of natural plant products may alsohave disorienting effects on the foraging behavior of honeybees and otherpollinators. Therefore, there is a need to generate information on naturalplant products relative to their metabolic products, acute and chronic toxicity,mutagenesis, allergenicity, and teratogenicity as in the case of synthetic

publication date

  • 2012