Efficacy of Double Nickel LC (Bacillus amyloliquefaciens D747 Strain) for Management of White Mold in Snap and Dry Bean

Abstract

White mold caused by Sclerotinia sclerotiorum is a serious disease affecting snap and dry bean production. Management is reliant upon fungicides to protect flowers from infection by ascospores. The inability to use conventional fungicides in organic production represents a substantial hurdle, although products approved by the National Organic Program (NOP) offer a substitute for disease management. In many cases, copper-based products are central to disease management programs in organic production, but the potential for crop loss from premature flower abscission in snap and dry bean owing to phytotoxicity when applied at high temperatures and for other undesirable environmental outcomes has driven interest in biopesticides registered by the NOP as alternatives. Five small-plot, replicated field trials (three in snap bean and two in light red kidney bean) were conducted across three years (2016 to 2018) to evaluate the efficacy of the biopesticide Double Nickel LC (Bacillus amyloliquefaciens D747 strain) for the management of white mold. Trials were inoculated with S. sclerotiorum ascospores to ensure uniform disease potential. The incidence of white mold in plots receiving two applications of Double Nickel LC (2.34 liters/ha) was not significantly different from the conventional fungicide standards. No significant difference in white mold incidence was found between 2.34 and 4.68 liters/ha of Double Nickel LC in either crop. Responses in pod yield components from improved white mold management in either crop were variable. The potential of Double Nickel LC for use in organic production of snap and light red kidney bean for management of white mold is discussed.