ABSTRACT
Disease management acknowledges the dynamic nature of plant pathogens within agroecosystems, and developing a disease management system in turn becomes a dynamic process. Agricultural practices have a marked effect on the incidence and severity of virus diseases. Repelling insect vectors, primarily aphids but also whiteflies, from fields by covering the soil with aluminum sheets or black or transparent polyethylene sheets, or by mulching the soil with some reflective material leads to delayed virus infection, decreased disease incidence, and greater yields. The overwhelming importance of using healthy virus-free stocks, seeds, and other propagating material is self-evident and is the basic prerequisite for managing plant disease. Certification schemes have been developed in various countries for the production of disease-free certified propagating material from a few virus-free plants. Cross-protection denotes the suppression of symptoms upon inoculation with a virulent strain in a plant perviously infected/inoculated with a mild strain of the same virus.
