natural-products-in-plant-pest-management

2 N.K. Dubey et al.mass migrations throughout history. Loss of crops from plant diseases mayresult in hunger and starvation, especially in less developed countries whereaccess to disease-control methods is limited and annual losses of 30–50 % arecommon for major crops. Owing to the congenial climatic conditions andparticular environment, the agriculture in tropical and subtropical countriessuffers severe losses due to pests (Varma and Dubey, 2001; Roy, 2003).Even during storage, foods are severely destroyed by fungi, insects andother pests. The deterioration in the stored food commodities is mainly causedby three agents, fungi, insects and rodents, under different conditions of storage.Insect pests cause heavy losses to stored grains, especially in humid andwarm areas of the world. The production of mycotoxins by several fungi hasadded a new dimension to the gravity of the problem. Fungi are significantdestroyers of foodstuffs during storage, rendering them unfit for human consumptionby retarding their nutritive value and sometimes by the productionof mycotoxins. According to FAO estimates, 25% of the world food crops areaffected by mycotoxins each year (Dubey et al., 2008). Generally, tropical conditionssuch as high temperature and moisture, unseasonal rains during harvest,and flash floods lead to mycotoxins. Poor harvesting practices andimproper storage during transport and marketing can also contribute to theproliferation of mycotoxins. Among the mycot oxins, aflatoxins raise the mostconcern posing a great threat to human and livestock health as well as internationaltrade. Aflatoxins are the most dangerous and about 4.5 billion people indeveloping countries are exposed to aflatoxicoses (Williams et al., 2004;Srivastava et al., 2008). Aflatoxins are potent toxic, carcinogenic, mutagenic,immunosuppressive agents, produced as secondary metabolites by the fungiAspergillus flavus and A. parasiticus on a variety of food products.The entire effort of growing a crop will be lost in the absence of cropprotection, resulting in financial loss to the grower. Therefore crop protectionagainst various pests is a must in agriculture. There is a need to reduce if noteliminate these losses by protecting the crops from different pests throughappropriate techniques. Currently, the role of crop protection in agricultureis of great importance and is a more challenging process than before. Hence,there is an urgent need to pay proper attention to control quantitative lossesdue to pest infestations of crops and their produce as well as qualitativelosses due to mycotoxin contamination.1.2 The Need to Search for Eco-friendly Control MeasuresThe most conventional and common method of pest and disease control isthrough the use of pesticides. Pesticides are the substances or mixture of substancesused to prevent, destroy, repel, attract, sterilize or mitigate the pests.Generally pesticides are used in three sectors, viz. agriculture, public healthand consumer use. These pesticides are largely synthetic compounds that killor deter the destructive activity of the target organism.Many farmers and crop growers use insecticides to kill infestinginsects. The consumption of pesticide in some of the developed countries is