If you care for roses, more than likely you’ve battled the fungal disease called black spot. There are many fungicides labeled for rose diseases in both the home and commercial markets. In contrast to other woody ornamental plants, we are fortunate that results of many rose fungicide research trials have been published over the past five years or so. What do these trials reveal about the efficacy of the fungicides on the market today? Quite a bit, actually! Refer to Table 1 for details.
The ratings in Table 1 are based on 16 unique research trial reports published in the American Phytopathological Society’s Fungicide and Nematicide Tests (http://www.plantmanagementnetwork.org/pub/trial/fntests). These trials were conducted by various researchers from around the United States. Thus, your results may vary based on application dose, timing, frequency and coverage, environmental conditions, and local pathogen population.
The following publications provide detailed information about the diseases and fungicides mentioned in Table 1: