Exploring Soil Microbial Diversity in North Dakota: Implications for Plant Disease Management

Soil fungal communities are crucial for soybean health, impacting nutrient cycling and disease dynamics. This study explored fungal diversity in soil samples from 63 soybean fields in North Dakota using a roll paper towel assay. Seven-day-old USDA soybean seedlings were used as baits, with roots covered by 20 g of soil and incubated for 10 days. After incubation, discolored tissues were surface-sterilized and plated on quarter-strength PDA to recover fungal isolates. Plates were incubated at 22±2°C for 10 days, and colonies were hyphal-tipped and transferred to fresh PDA for identification. Fungal genera identified included Alternaria, Cladosporium, Fusarium, Penicillium, Phytophthora, Pythium, Macrophomina, Rhizoctonia, and Rhizopus. Among them, Fusarium was the most prevalent genus, followed by Phytophthora and Pythium, all known plant pathogens. This study highlights the significant presence of plant pathogens in North Dakota soils and establishes a foundation for future research to improve soybean health.