Characteristic agro-ecological features of soil populations of bean root rot pathogens

Associations of soil populations of the predominant root rot pathogens with a number of agro-ecological features were assessed in bean production fields in Zanjan province, Iran. According to multivariate analyses, bean market class, herbicide, P-fertilizer, previous crop, region, field size, sand content, soil pH and texture, and urea use affected densities of Fusarium oxysporum and Macrophomina phaseolina populations in farm soils. For F. solani, bean class, herbicide and P-fertilizer significantly affected soil population density. Region, soil pH and sand were associated with Rhizoctonia solani populations in soil. Lower total soil populations of four root rot pathogens were associated with Red beans, larger fields, the Kheirabad and Khodabandeh regions, P-fertilization, lack of trifluralin and urea application, and at higher levels of electrical conductivity, pH and sand of field soil. With this knowledge it should be possible to identify bean-root-rot-suppressive agro-ecosystems.