There are three supplemental datasets for this thesis including: 1) Field trials https://doi.org/10.5683/SP/LNSIR7; 2) Amino acid concentrations https://doi.org/10.5683/SP/73AJUT; and 3) Sugar content https://doi.org/10.5683/SP/U3YGQNThe potential impact of predicted climate change on Microdochium nivale, which causes Microdochium patch on turfgrasses was investigated. Turfgrasses exposed to temperature fluctuations exhibited increased yellowing caused by M. nivale compared to a constant lower temperature incubation. The effect of increased CO2 (from 400 ppm to 800 ppm) on M. nivale hyphal growth, percent yellowing, and biochemical response was assessed for Agrostis spp. and Poa annua cultivars. The efficacy of the resistance activator, Civitas + Harmonizer, was assessed under conditions of increased CO2, two temperatures, and field conditions. Civitas + Harmonizer often decreased disease symptoms, and suppression varied by cultivar and environmental conditions. Elevated CO2 did not affect the growth of M. nivale, although evidence from growth room trials suggests it may decrease Microdochium patch disease severity in the future. However, the interactive effects of temperature, snow cover conditions, and moisture availability in the field under future conditions is unknown
