Figure 1. Tar spot disease triangle showing how A. the pathogen, host and environment can influence the amount of disease that may develop in crop canopy. B. Reduced disease potential if initial pathogen inoculum is decreased in a field. C. Reduced disease potential if host plant has improved resistance to the pathogen. D. Reduced disease risk if environmental conditions are not favorable for disease development. E. Reduced disease risk if all three factors are minimized.