Abstract
A systems model to predict the percentage (100AT) of rice hills infected with rice dwarf virus (RDV), which is transmitted by the green rice leafhopper, Nephotettix cincticeps UHLER, is presented. For the relationship between AT and the density (NA) of adult immigrants to the production rice field, the following submodel is used : AT=1-exp(-aNALP), where a is the rate (number of hills) of successful transmission of RDV by an infective adult per day, L is the mean longevity of adults, and P is the proportion of infective individuals in the population. NA can be correlated with the density of leafhoppers developing on wild hosts in a fallow paddy field before their dispersal. Simulation suggested that, assuming P=0.05, a=1 and L=10, about 0.4 adult immigrants per/hiss will give rise to 15% RDV-infected rice hills (a tolerable injury leve) inproduction field requiring control measures.
