Identification of meteorological predictors of Fusarium graminearum ascospore release using correlation and causality analyses

Abstract

Fusarium head blight (FHB), caused by the plant pathogen Fusarium graminearum, is a significant threat to small grains production worldwide. Additional knowledge is required to clarify the influence of meteorological conditions on the release of ascospores of F. graminearum. Here, a new application of causality analysis is used to determine how meteorological conditions cause ascospore release. Two types of causality analyses, convergent cross mapping and multivariate state space forecasting, were applied to field measurements of airborne ascospores of F. graminearum over two years. Convergent cross mapping identified relative humidity, solar radiation, wind speed, and air temperature as predictors of ascospore release. Multivariate state space forecasting identified solar radiation and relative humidity as effective predictors of ascospore release. Increased concentration of ascospores in the atmosphere primarily occurred during periods of high relative humidity, low solar radiation, and low wind speed. Results from this study may assist producers in managing FHB in small grains by narrowing the timing and application of fungicides around major ascospore release intervals predicted by meteorological conditions.