natural-products-in-plant-pest-management

92 K.A. Raveeshafood, particularly species of Aspergillus and Penicillium. Grain produced isnot a grain until it is consumed without quality loss (Neergaard, 1977). Inspite of the developments in the methods of food preservation, nearly 30% ofthe food produced is lost during storage, due to poor handling and storagepractices.The incessant and indiscriminate use of chemical pesticides in agriculturehas resulted in drug resistance, residual toxicity, and has caused soil andwater pollution. This has necessitated the search for natural eco-friendlyalternatives, which are biodegradable and non-toxic to non-target species.Plants are a repository of novel biomolecules with various biological activities.Among the 250,000–500,000 species of plants available on earth, thenumber of plants screened phytochemically is a small percentage, amongthese the number of plants screened for various biological activities is infinitesimallysmall. In recent years there have been serious efforts to screenplants for various biological activities and the scientific endeavour is focusedmainly on utilizing plants for human health and least towards plants forplant health. Considering the fact that large amounts of synthetic pesticidesknown to cause environmental pollution are used in present-day agriculture,there is an urgent need to search for natural eco-friendly alternatives. Antimicrobialsof plant origin appear to be one of the safest and eco-friendlyalternatives. Hence, there is a need to search for antimicrobials of plant originto manage field crop loss in general and to prevent biodeterioration of grainsduring storage in particular.Clinical microbiologists have two reasons to be interested in antimicrobialsof plant origin. First, it is very likely that these phytochemicals orbiomolecules will find their way into the arsenal of prescribed antimicrobialdrugs. Second, the public is becoming increasingly aware of the problemswith and side effects from the over prescription and traditional use ofantibiotics (Cowan, 1999).Agricultural microbiologists have many more reasons to be interested inantimicrobials of plant origin: (i) it is very likely that these phytochemicalsmay find their way into the array of antimicrobial drugs prescribed; (ii) it isknown that the effective life span of any antimicrobial is limited, hence newerantimicrobials are necessary; (iii) it may help to overcome the rising incidenceof drug resistance amongst pathogenic microbes and the mechanismof action could be different; (iv) the phytochemicals present in plant extractsmay alleviate the side effects that are often associated with synthetic antimicrobials;(v) phytomedicines usually have multiple effects on the plantbody and their actions are often growth promoting, more systemic andbeyond the symptomatic treatments of disease; and (vi) it may help in developingcost effective remedies that are affordable to the population (Cowan,1999; Doughari, 2006).Finding healing powers in plants for human health needs is an ancientidea and practice. Searching herbal remedies for crop protection in generaland prevention of biodeterioration in particular is recently gaining importance.Agricultural microbiologists around the world are evaluating a numberof plant extracts for antimicrobial activity against important plant