Effects of Environmental Factors on Plant Disease

When the wide variety of factors that combine to produce environmental effects on disease development and expression are examined, the complexity of ecological interactions become obvious. To unravel this complexity, many factors must be considered including survival of inoculum from one crop to another, provision of suitable conditions for infection, sporulation of the pathogen on the diseased plants and transference of inoculum to healthy plants, defensive mechanisms in host plants, effects of environment on fungus and host, influence of the growth of the host on the microclimate in the crop, effects of interactions between host and pathogen, and interactions between microorganisms in the soil, or on aerial parts of plants, in respect to infection by any specific pathogen. In this paper particular attention will be paid to the effects of physical factors and their interactions. The effects of temperature is looked at in depth. 106 references.