Associations among the communities of soil-borne pathogens, soil edaphic properties and disease incidence in the field pea root rot complex

Field pea production is greatly impacted by multiple soil-borne fungal and oomycete pathogens in a complex. The objectives of this research were to 1) identify the soil-borne pathogens associated with field pea in North Dakota and; 2) develop prediction models incorporating the occurrence of the soil-borne pathogen communities, soil edaphic properties and disease incidence. Soil and plants were sampled from 60 field pea fields in North Dakota during 2014 and 2015. Plants (1500 across two years) were rated for both root rot and soil-borne pathogens isolated from roots. Soils were analyzed for edaphic properties. Indicator species analysis was used to identify soil-borne pathogen communities. Logistic regression was used to determine associations and develop prediction models. Survey results from 2014 and 2015 indicated that the most prevalent soil-borne pathogens identified in field pea fields were Fusarium spp. and Aphanomyces euteiches. Five soil-borne pathogen communities were identified; three of which had statistically significant associations characterized by (1) Fusarium acuminatum, (3) A. euteiches, and (4) Fusarium sporotrichioides. The occurrence of the three communities were associated with clay content, soil pH, Fe2+, and K+. Disease incidence was associated with the presence of either community 1 or 3 and K+. The results generated from this research will contribute to the development of management strategies by providing a soil-borne pathogen community prediction tool.