Co-Authors:
Marcus, R., Department of Statistics and Operations Research, Agricultural Research Organization, The Volcani Center, POB 6, Bet Dagan, 50250, Israel
Abstract:
Deterministic and stochastic versions of the logistic model were applied for describing increase of plant diseases. The stochastic version of the logistic model is based on the addition of a random component to the growth rate per unit infection, as previously used for analysis of insect population abundance. The models were fitted to disease progress curves derived from a real data set consisting of disease assessments of melon plants in Israel infected by zucchini yellow mosaic virus (ZYMV). The results showed that the random component in the stochastic version was estimated as being small. The autocorrelations of the residuals were lower for the stochastic version of the logistic model than the corresponding values of the deterministic logistic model. For small data sets the statistical advantages of the stochastic version of the logistic model over the (simpler) deterministic version were not significant. © 1991.