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Poster: Biology & Disease Mgmt: Chemical Control


Efficacy of three soybean fungicide seed treatments against Pythium species in seed plate and growth chamber assays
K. SCOTT (1), A. Vargas (1), M. Eyre (1), A. Dorrance (1) (1) The Ohio State University, U.S.A.

Recent studies have reported a wide range of sensitivity to metalaxyl in Pythium species in Ohio, thus new active ingredients are important for management of seed and seedling blight. The objective of this study is to determine the efficacy of three seed treatments with a combination of active ingredients for oomycetes against a diverse population of Pythium species. Commercial formulations of Intego™ Suite, Cruiser Maxx® Advanced, and Acceleron® were applied to seed at labeled rates and evaluated with Pythium isolated from fields across Ohio in both a plate assay and a cup assay. In the cup assay, the mean root score was significantly lower in all fungicide seed treatments compared to the control, but there were no significant differences between treatments. In the seed plate assay, there was a significant difference for mean seed rot score between all treatments. Acceleron® had the lowest seed rot score towards all Pythium species, followed by Intego™ Suite, Cruiser Maxx® Advanced, and the non-treated check, respectively. These seed treatments may provide adequate protection against Pythium infection in soybean seed and seedling stages. In addition, the seed plate assay may be used to efficiently test for isolate pathogenicity and the efficacy of seed treatments.