I apologize for this delayed reply to your gardening question and hope it is still helpful to you.
Yes you can dig and transplant that rose but the best time is in the late fall as the stresses are less. The risks are much higher trying to move it now. There are a number of sprays that are effective against black spot but they must be used preventatively for best results, rather than trying to cure an infection already well under way.
Some of the better product ingredients for black spot control include myclobutanil, propiconazole, triforine and mancozeb. Alternating between one of the first two and one of the second two products may work best.
Thanks for the question. Best wishes for a wonderful gardening season. Please stop in again soon!
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