Some approaches to prediction of potato early dying disease severity

There are two control procedures available to growers who have fields that may develop severe potato early dying. The first, use of long crop rotation sequence, may result in only marginal control. The second, soil fumigation, is costly; and while providing effective control in many cases, has failed in others. Because of the cost of fumigation and its limited effectiveness in some situations, it may be helpful to predict the potential severity of the disease and subsequent yield loss. One approach to disease and yield loss prediction could be to rely on historical knowledge of early dying severity and yield in a field. Another approach is to use soil inoculum levels as an indicator of potential disease severity and yield loss. Because severity of potato early dying may vary from year to year in a given field as a result of differing environmental conditions, neither historical knowledge nor estimated soil inoculum levels may be sufficient for predicting disease severity. These methods may, however, provide an estimate of the potential for severe early dying to occur. Modelling the impact of early dying on plant growth and yield as a function of environmental parameters and presence of inoculum may provide a means of setting confidence limits of an estimated disease severity and yield loss based on historical knowledge or knowledge of inoculum load.