Physical Techniques for Biological Crop Disease Management

Abstract

Application of physical techniques involving the use of heat, solar energy and irradiation may reduce the pathogen population or weaken their pathogenic potential. Heat treatments are applied as hot air, hot water, aerated steam and solarization. Heat treatments are very effective against seed borne and postharvest pathogens, when applied as hot air or hot water. Heat as steam has been applied for soil disinfestations Plant propagative materials are treated with hot air, hot water and aerated steam to produce disease-free planting materials. Thermotherapy is effective in eliminating viruses from planting materials and whole plants. It is combined with tissue culture methods to develop virus-free nursery stocks. Soil solarization using transparent polyethylene sheets is an effective selective soil treatment option with solar energy, resulting in reduction in pathogen population and activation of antagonistic microorganisms in the soil. Polyethylene mulch is useful for reducing the incidence of several fungal and some of the viral diseases. Irradiation with UV-C has favorable effect on fruits and vegetables which exhibit resistance to postharvest pathogens. Seed treatment with UV-C reduces infection by seedborne pathogens also.