Simulation Models of Rice Blast Epidemics

Abstract

In Japan, simulation models of rice blast epidemics have been developed as a tool for disease forecasting services in the public domain since the early 1970s. Later, the government changed the policy on disease management and started to emphasize lesser dependency on fungicides. Consequently, the disease forecasting had to introduce the concept of integrated pest management (IPM). An idea was proposed to use a simulation model for blast forecasting as a decision support system (DSS) based on IPM strategy. However, it is difficult to determine economic injury level (EIL) and action threshold (AT) of blast disease based on objective evidences. Also, accuracy and precision of simulation models of natural systems is innately insufficient. These two issues challenge the usefulness of simulation models for contemporary rice blast management. However, only if the EIL are subjectively determined by the decision-makers, forecasting with a simulation model can play a major role for IPM program for rice blast disease. The next step should be large scale field trials to test the usefulness of this system. The results certainly become strong evidences to encourage introducing the system into rice blast management programs.