06/24/2026
20260624 This photos was emailed by CEA Lonnie J. indicating that the homeowner has been "disposing diseased leaves" of this rose plant. Also noted was that homeowner had been treating with fungicide but it keeps getting worse. WHAT is it and WHAT is going on? From the photo, it looked like a bad case of black spot disease on a susceptible rose cultivar. Unfortunately, we did not have the cultivar name nor did we have the type of fungicides that were used, including when and how they were used. It also just happened that we have a Extension factsheet (PLPM-PU-049) on this fungal disease of roses: https://bit.ly/44kDEAs
Nonetheless, this is another year where it seems that many parts of Texas is wetter, humid and somewhat milder. It is a good year for diseases. In the case of blackspot, it is very likely that multiple applications of fungicide product must be used at the proper timing to help prevent new infections. A challenge, but not impossible. I would think that with this particular situation, some pruning out of infected plant parts and sanitation (cleaning out diseased plant debris, along with judicious use of fungicide can help to manage this disease. -KO