natural-products-in-plant-pest-management

6 Natural Products asAllelochemicals in PestManagementROMAN PAVELACrop Research Institute, Prague, Czech RepublicAbstractAllelochemicals are one of the most plentiful groups of substances in the vegetablekingdom. The significance and use of these chemicals in nature are as varied as allelochemicalsthemselves. Allelochemicals also include a group of substances called allomones.These substances are created by plants as a defence against phytophagousinsects and comprise repellents, anti-ovipositants and antifeedants. This group ofplant metabolites can be of practical use in many areas of human activity. This chapterdeals with possibilities of using plant extracts containing allomone in the protectionof plants against pests. Substances with antifeedant effects, in particular, appear to behighly promising for the development of new, environmentally safe insecticides. In thischapter, we have therefore focused mostly on this group of substances and criticallyconsidered the perspective of using antifeedant substances in plant protection.6.1 IntroductionPlants have developed alongside insects since the very beginning of theirexistence. Thanks to their common history, very fragile mutual relationshipshave formed between individual plant and insect species, which we aretrying to clarify today using scientific approaches. On the one hand, plantsutilize insects, especially as their pollinators, and on the other, insects useplants as the source of their food. Therefore, for balanced mutual interactionsbetween plants and insects, communication and mutual influence must existbetween them to prevent uncontrolled excessive reproduction of any speciesin order to maintain equilibrium in the ecosystem with maximum possiblebiodiversity. Plants thus created many strategies in the course of theirco-evolution to protect themselves efficiently against insect pests, and theinsects try to circumvent such strategies. Understanding their mutual relationshipshelps us not only to understand the world around us but alsoprovides information that may lead to a practical use.© CAB International 2011. Natural Products in Plant Pest Management134 (ed. N.K. Dubey)