Study on the infections status and important agronomic factors in severity of black shank disease of tobacco in Golestan province

Phytophthora nicotianae Breda de Haan (=P. parasitica Dasture) is the causal agent of black shank disease and one of the most important pathogen in tobacco fields. In order to study the infection status of this disease in tobacco fields of Golestan province, 45 tobacco fields in five different regions of Gorgaan (Taghartappeh, Jafarabad, Ghorogh, Nodehmalek and Valeshabad) and four different regions of Aliabad (Pichakmahaleh, Baraftan, Fazelabad and Elazman) selected in 2014. The amount of disease was recorded during the infection period from the beginning of symptoms appearance, weekly. Stat Graphics Centurion XVI and Harward Graphics softwares were used to statistical analysis and draw charts of the development of epidemiological models, respectively. The factors influencing the epidemiology of disease were determined using two statistical methods of analysis of discriminant analysis and logistic regression. Based on the highest disease incidence there were no significant differences between regions, but there were significant differences (P