P-073 - Identification and Evaluation of Biological Control Agents from North Dakota Soybean Fields for the Control of Multiple Pathogens

Sclerotinia sclerotiorum, Rhizoctonia solani, and Macrophomina phaseolina are fungal pathogens resulting in significant yield and economic losses globally. These pathogens cause substantial loss in North Dakota (ND) soybean fields by causing the diseases Sclerotinia stem rot, Rhizoctonia root rot, and Charcoal rot respectively. To improve disease management, we’ve explored biological control agents (BCAs) derived from bulk soil collected from ND soybean fields as an alternative to chemical control. This study aims to isolate and characterize BCAs collected across ND. So far, 218 fungal isolates from six counties sampled in 2023 were screened for biological control activity against the pathogens. Preliminary data from dual culture and detached leaf assays indicate nine fungal isolates inhibit the growth of pathogens, although differential inhibition is present depending on the pathogen. These ten identified fungal isolates were also evaluated for suppression of R. solani under greenhouse conditions when applied as a seed treatment. Based on molecular identification, eight belong to Aspergillus, Clonostachys, Penicillium, and Fusarium genera while two are still unknown. Some identified BCAs exude unknown compounds to hinder fungal growth while others compete for resources, suppressing the pathogen`s mycelial and sclerotial development. Liquid chromatography-mass spectrometry will be used to identify these antifungal compounds. This ongoing study shows progress in discovering and characterizing BCAs from bulk soil as efficient antagonists against multiple soilborne pathogens.