natural-products-in-plant-pest-management

7 Potency of Plant Productsin Control of Virus Diseasesof PlantsH.N. VERMA 1 AND V.K. BARANWAL 21 Jaipur National University, Jaipur, India; 2 Advanced Centre of PlantVirology, New Delhi, IndiaAbstractThe exploitation of the inherent resistance phenomenon and manipulation of inducibledefence in plants is currently receiving much attention by researchers to control virusinfection. Recent advances in the molecular biology of resistance to virus infectionhave presented new approaches for making susceptible crops resistant against virusinfection. These approaches include pathogen-derived resistance to viruses (coatprotein-mediatedresistance, movement-protein-mediated resistance, replicase- andprotease-mediated resistance) and virus resistance through transgenic expression ofantiviral proteins of non-viral origin. Endogenously occurring substances in a fewhigher plants have also been reported to induce systemic resistance in susceptiblehosts against virus infections. Ribosome-inactivating proteins (RIPs) may also play animportant role in the prevention of virus infection.7.1 IntroductionViruses prove to be a menace to humans and the environment because oftheir disease-causing nature. They harm crops and cause economic losses.The recent outbreak of cotton leaf curl virus disease in cotton in the northerncotton-growing region of India has led to a huge yield loss of cotton fibre.Approximately 12,000 hectares of cotton were affected by leaf curl virusdisease during 1996 in Rajasthan alone. An annual loss of US$300 million iscaused by mungbean yellow mosaic virus (MYMV) by reducing the yield ofblack gram, mungbean and soyabean (Varma et al., 1992). The worldwidelosses caused by viral diseases are estimated at about US$60 billionper year.To reduce losses, scientists have explored several strategies to controlvirus infection. However, it is the exploitation of the inherent resistancephenomenon and manipulation of inducible defence in plants that arereceiving much attention from researchers. The common approach for© CAB International 2011. Natural Products in Plant Pest Management(ed. N.K. Dubey) 149