The assessment of disease incidence and crop loss

Abstract

One of the most difficult problems of plant pathology is that of accurately assessing the incidence of disease in crops and relating this to subsequent loss in terms of yield and money. This is a complex subject whose numerous ramifications have been explored in detail by Chester (1950). It is important to the farmer who has to decide whether the monetary losses due to a disease warrant the trouble and expense of applying control measures. The monetary losses caused by diseases or the expense of controlling them are likely to be passed on to the consumer in the form of higher retail prices or government subsidies to the farmer, so that all users of agricultural produce will be adversely affected. Those responsible for the organization of research on plant diseases must have reasonably accurate knowledge of the economic importance of individual diseases if they are to apply their limited resources to the best advantage. This applies to all forms of plant damage whether due to pathogens, insect pests, nematodes, weeds, or other causes.