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POSTERS: Abiotic interactions

Relationship between soil fungal densities and soil chemical properties in Pennsylvania.
Ananda Bandara - The Pennsylvania State University. Alyssa Collins- The Pennsylvania State University, Alyssa Collins- Southeast Agricultural Research & Extension Center, Brandon Wilt- The Pennsylvania State University, Dilooshi K. Weerasooriya- The Pennsylvania State University, Paul Esker- The Pennsylvan

Soil borne diseases cause significant yield losses in many economically important crops in the United States. Species of Fusarium, Pythium, and Phytophthora and Rhizoctonia solani are among the most common soil borne fungal pathogens. The objective of this study was to investigate the relationship between selected soil chemical properties and population densities of different fungi in soil. Soil samples were systematically collected from 22 locations in Pennsylvania covering 17 counties. Enumeration of fungal colonies was conducted using soil serial dilutions on selective media (Fusarium = Nash and Snyder; Pythium = P5ARP; Phytophthora = P5ARP + hymexazol; Rhizoctonia = Ko and Hora). Organic matter (OM), cation exchange capacity (CEC), pH, and nutrients (P, K, Mg, Ca, Zn, Cu, S) of soil samples were determined. Pearson correlation analysis showed a significant relationship between soil Fusarium density (CFU/g) and S (r = 0.74, P < 0.0001). Pythium density was significantly correlated with K (r = 0.71, P = 0.0002) and CEC (r = 0.58, P = 0.0051). Neither Rhizoctonia nor Phytophthora densities were significantly correlated with any of the measured properties. Therefore, despite their importance for enhanced crop production, S and K have the potential to increase inoculum densities of soil borne Fusarium and Pythium species respectively and could indirectly promote crop’s susceptibility to soil borne diseases caused by these fungi.