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Pest
Guys
My roses looked great until last summer. Dark spots appeared on the leaves which
then turned yellow and eventually fell off. The bush seems less healthy this
year. What should I do? (Janice, Fayetteville)
These dark (and sometimes downright scary) leaf spots that you are probably
describing may be a severe fungus disease that can be a real headache for
lots of rose growers. This disease is called "Black Spot" and can often
cause the leaves to become yellow, leading to heavy leaf drop, which in turn
weakens the plant. The disease tends to be worse in hot and humid weather. A
diligent spray schedule with an appropriate fungicide may be required,
especially if your roses have had a disease "history". Materials containing
the active ingredients of myclobutanil or triforine are commonly used. Be
sure to encourage dry leaves, since the disease often shows up after the
leaves have been wet for just a few hours! (See
