Effect of fungicide seed treatments and cultivars on Pythium damping-off and root rot of edamame soybean
F. Baysal-Gurel (1), J. Mera (1), S. A. MILLER (1)
(1) The Ohio State University, Wooster, OH, U.S.A.
Phytopathology 101:S14

Production of edamame soybeans is increasing in Ohio, but Pythium damping-off and root rot can reduce productivity. The efficacy of fungicide seed treatments and cultivars against Pythium spp. was tested in 2009 and 2010. Seedling emergence and severity of Pythium root rot were assessed 3 and 10 weeks after seeding, respectively. Pythium colonies were recovered from root samples on PIBNC medium. Plant biomass was determined based on the weight of plants from the center 5 ft of each row. Seed treatment with Apron XL+Maxim 4 FS+Cruiser (w or w/o Rhizobium inoculant) increased emergence and reduced root rot severity and the number of Pythium colonies compared to the untreated control in both years. Plant biomass was higher in plots treated with Apron XL+Maxim 4 FS+Cruiser than in the untreated control in 2010. Percent emergence was higher in the cultivar BeSweet 2015 than in BeSweet 2001 and BeSweet 292 in 2009. However, emergence was higher in BeSweet 292 than the other two cultivars in 2010. BeSweet 2015 had lower root rot severity and fewer Pythium colonies than BeSweet 2001 and BeSweet 292 in 2009 but there were no differences between cultivars in biomass. BeSweet 2015 had lower root rot severity than BeSweet 2001 and more Pythium colonies but higher biomass than the other two cultivars in 2010. Both cultivar and fungicide treatment should be considered to improve edamame emergence and root health in Pythium-prone soils.