Submitted to: Pacific Northwest Vegetable Association Proceedings
Publication Type: Proceedings
Publication Acceptance Date: October 1, 2001
Publication Date: November 1, 2001
Citation: MIKLAS, P.N. MANAGING SCLEROTINIA ON BEANS. PACIFIC NORTHWEST VEGETABLE ASSOCIATION PROCEEDINGS, 2001:133-136. 2001. Technical Abstract: White mold (caused by the fungal pathogen Sclerotinia sclerotiorum Lib. DeBary) is one of the most important fungal diseases of common bean (Phaseolus vulgaris) worldwide. It is also one of the most difficult bean diseases to control. An integrated disease management scheme is critical for effective control of the disease. A three-pronged strategy involving management of the pathogen, environment, and host is used to combat this disease. Means for controlling the pathogen include soil treatments, biocontrol, fungicide applications, and cultural practices. Fungicides are widely used and are by far the most important component of the disease control arsenal. Sclerotinia requires moderate temperatures and wet conditions to cause epidemics, with wetness the most critical element. Any practice that opens up the plant canopy, enabling greater sunlight and wind penetration, will promote a drier microclimate within the canopy that is less conducive to white mold disease. N-fertilization rates and irrigation amounts and timing can be managed to promote an open and drier plant canopy less favorable to white mold disease. For the host, combining physiological resistance with avoidance mechanisms (upright plant architecture, open canopy, reduced lodging), is the current breeding strategy for minimizing yield losses due to white mold. Many growers have come to realize the presence of white mold in their dry bean fields as an indicator of high yield potential, because generally conditions favorable for yield are also conducive to white mold disease. To maximize yield under white mold pressure requires an integrated approach involving management of the pathogen, environment and bean host.