Macrophomina phaseolina is a generalist ascomycetic fungal pathogen, capable of infecting over 500 genera of plants and limiting yield in crops grown in Mississippi. Recent documentation of M. phaseolina on Impatiens × hybrida, a newfound host, has merited multiple experiments to quantify the exact nature of this relationship. Despite M. phaseolina being a soil-borne pathogen, disease symptoms were only reported in aboveground tissue. Mode of infection experiments revealed both above and belowground tissues are susceptible to infection. In vitro experiments identified the optimal temperature for the growth of M. phaseolina to be 26°C, where more than 10x the accumulated biomass resulted compared to samples grown at 37°C. Impatiens × hybrida hosts were particularly prone to infection at temperatures above 27°C. In vitro fungicide assays revealed Banrot and T-Bird to be suitable chemical control agents for limiting M. phaseolina growth.