Macrophomina phaseolina hot spots and correlations with soil and plant factors

Abstract

Macrophomina phaseolina is a fungal pathogen capable of infecting over 500 plant species across the world and one of the most important pests of soybeans in Kansas. Investigation has been conducted on M. phaseolina's presence, due to its effects on agriculture and crop yield. Conversely, minimal research has examined the fungal pathogen's significance in native prairie communities, its correlation with environmental factors, or its spatial structure. Our goals are to better understand M. phaseolina's behavior in native prairies in hopes to apply these insight to agricultural systems. In the summer of 2020, we quantified the spatial structure of M. phaseolina in a 15 x 15 m grid of untilled tallgrass prairie and correlated M. phaseolina's abundance with soil and plant characteristics. We found a high variability in the density of M. phaseolina and limited evidence for spatial aggregation of pathogen abundance. Additionally, bivariate analysis revealed weak correlations between pathogen abundance and individual soil properties and no correlation between pathogen abundance and plant variables. The results found rule out several key factors and suggest a better understanding of how physical disturbance and the mechanism of spread for M. phaseolina contribute to the large differences in density observed.