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Poster: Biology & Disease Mgmt: Oomycetes


The Effect of Increased Soil Fertility on Seedling Disease Development of Soybean in Ohio
M. EYRE (1), S. Culman (1), A. Dorrance (1) (1) The Ohio State University, U.S.A.

Low or high soil fertility levels have been shown to have potential secondary impacts on root pathogens, some of which decrease yield. Fertility recommendations for soybean in Ohio are over 20 years old and one proposed scenario is that more phosphorus and potassium may be required to support the increase in yields over the past 2 decades. Therefore, the objective of this study was to evaluate the impact of higher rates of P, K, and P + K on seedling diseases caused by oomycetes in both field and greenhouse trials. Field trials were carried out at two locations in 2014 and three locations in 2015 at fields each with a known history of seedling disease. Stand counts, percent emergence, and yield were not significantly different between treatments at any of the locations. However, a greater number of Pythium spp. were recovered from plants with the addition of K. In greenhouse assays using soil collected from the same infested fields, final stand and root weights were significantly (P<0.05) higher in pots without fertility treatments for one of the two locations. Further monitoring of the influence of higher rates of K at the time of planting on disease development of soil borne diseases caused by oomycetes is warranted.