Comparing models for temporal progress of zonate leaf spot (Gloeocercospora sorghi) disease in sorghum (Sorghum bicolor)

摘要

Field studies were conducted during 2004-06 rainy (kharif) seasons to analyze the temporal progress of zonate leaf spot (Gloecercospora sorghi. Bain & Edgerton). Two growth models (Gompertz & logistic) were used to fit empirically derived disease progress curves. The Gompertz transformation effectively linearized the disease progress for all the 3 seasons. A close agreement was observed between the predicted and observed disease level in case of Gompertz model which accounted for > 90% of disease severity (P < 0.01) along with low root mean square error (0.053 to 0.061) as compared to logistic model (R*(2) > 80%, RMSE* = 0.063 to 0.105) over the years. The Gompertz model was found to be best fit over the years for describing zonate leaf spot disease progression in a natural inoculum population of G sorghi on sorghum (Sorghum bicolor L.).