Linkages of Farmers' Operations with Rhizoctonia Root Rot Spread in Bean Crops on a Regional Basis
2013
Naseri, Bita
The associations of Rhizoctonia root rot (RRR) with a number of agronomic and yield variables were characterized at different growth stages in 122 commercial bean fields in Zanjan, Iran. A lower RRR incidence was detected in red beans compared with white beans. RRR incidence was greater in drought‐exposed fields compared with drought‐free fields. RRR incidence was higher following frequent irrigations at 2‐ to 3‐day intervals than at 4‐ to 9‐day intervals. The highest RRR incidence was associated with the densest category of plant populations and with the deepest plantings at 10–22 cm. Beans grown following alfalfa, bean and maize had a lower disease than rotations with potato. RRR incidence was greater in fields that received 50–500 kg/ha of urea compared with nonfertilized fields. RRR‐affected fields were recognized with a closer irrigation, earlier and deeper planting, denser weed population and lower yields than RRR‐free fields. According to loadings for second principal component, planting density and depth, urea usage and weed density corresponded with RRR incidence. Findings extend our understanding of RRR epidemics in diverse bean cropping systems.
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