The influence of high temperature stress and herbicides on the susceptibility of creeping bentgrass (Agrostis palustris) to Curvularia lunata

Abstract

The status of Curvularia lunata as a primary pathogen of creeping bentgrass (Agrostis palustris) has been debated in the literature for many years. The most recent and most complete evidence indicates that this fungus is a weak pathogen, colonizing only senescing tissues. In the present study, four groups of experiments were conducted: 1) The effects of five herbicides on the growth of C. lunata in vitro were determined. 2) Acute high temperature stress was evaluated as a predisposing factor in the susceptibility of creeping bentgrass to C. lunata. 3) The effects of acute high temperature stress and exposure to five different herbicides on creeping bentgrass were evaluated together and separately. 4) The potential of chronic, moderately high temperature stress and exposure to five herbicides when occurring separately and together to serve as predisposing factors on the susceptibility of creeping bentgrass to C. lunata were evaluated. It was found that effects of the herbicides on the growth of C. lunata depend on both the specific herbicide and the concentration. High temperature stress and herbicide exposure increase the colonization of creeping bentgrass by C. lunata only to the extent that these treatments produce moribund plant tissue.