Charcoal rot of bean in diverse cropping systems and soil environments

Associations of charcoal rot (CR) with a number of bean cropping and soil characteristics were investigated at pod maturity in 48 bean producers' fields of Zanjan, Iran. According to Wald tests, the index of bean CR varied between field locations. Among the factors tested, soil clay and sand content affected the CR index at pod maturity. Based on multiple regression analyses, high pH and sand content of field soil, large field size, early and deep sowing, and no use of herbicides favoured CR. Beans cultivated following legumes or cereals had a higher CR level in comparison with tomato or potato as preceding crops. These findings enhance our understanding of CR epidemics occurring under commercial production conditions. They could be used for optimizing an integrated bean-CR-management program.