Hi. My very prolific explorer rose has suddenly developed some curled leaves and pink, fuzzy spots. A new ( to me) type of mildew? Please advise. Thank you.
Thank you for contacting the Toronto Master Gardeners with your most interesting question. You have not submitted a photo so it is a bit difficult to say definitively what it is that you found on your rose leaf. I am including a photo for you to compare for your reference.
You may be have Erineum Gall on your rose leaf.
According to the University of Minnesota Extension site, “galls are formed by insect/mite feeding or egg-laying activity. Either mechanical damage or salivary secretions (introduced by insects and/or mites) initiate increased production of normal plant growth hormones. These plant hormones cause localized plant growth that can result in increases in cell size (hypertrophy) and/or cell number (hyperplasia). The outcome is an abnormal plant structure called a gall.”
The Erineum Gall manifests itself as pink fuzz on the leaf surface. Control is not required since the gall does not affect the health of the plant.
If after comparing the picture of the gall to your rose you think it is something else please send us a clear closeup picture to help us better identify the problem.