To get the most from a fungicide application within an IPM program, it is important to proceed in an informed and intelligent manner. Keep in mind that fungal pathogens of plants are dependent on a susceptible host and specific, favorable environmental conditions in order to cause disease. Planting resistant turfgrass cultivars (see Turfgrass Selection: Species and Cultivars) and modifying the growing environment to help reduce disease will make fungicides more effective. The most important aspect of disease control is correct identification of your target pest. It is imperative to be certain of the identity of the pathogen prior to any fungicide application. If in doubt, send a turf sample to the UMass Extension Plant Diagnostic Lab (ag.umass.edu/services/plant-diagnostics-laboratory). Knowing the pathogen allows you to know which grass species are susceptible or resistant, the optimum conditions for disease development, and the sensitivity of the pathogen to specific fungicides.
If you experience reduced efficacy or complete failure from fungicide applications to control dollar spot and athracnose, the UMass Pathology Lab offers both in vitro and molecular assays to assess potential fungicide resistance in the disease population. See the Fungicide Resistance Assay page of this web site for information.
Table 22. Commonly used turf fungicides and the diseases they are labeled to control or suppress.