9ac1836f_Pests___Diseases__Problem_Symptom
[Cause] Blackspot. This fungus disease is most common in humid and rainy conditions; the fungus spores germinate in water. Once a plant is infected, the fungus will remain in the canes through the winter and reappear on the next season's growth. VERY common in the Pacific Northwest. [Solution] There is no chemical cure for infected plants. Plan on spraying with fungicides on a regular basis to prevent infections. Prune out affected canes in your early spring pruning, and apply a fungicide before the leaves open. To prevent blackspot from infecting new plants, spray with a fungicide as soon as leaves appear in spring, and repeat according to label directions. If symptoms appear, remove and destroy all infected leaves, including those on the ground. Do not water plants from above; wet leaves are hospitable to germinating spores. [Problem/Symptom] 
Circular black spots 1/4 inch in diameter appear on upper leaf surfaces. Each black spot has a feathery margin and is surrounded by a yellow halo. As the spots enlarge and coalesce, the entire leaf turns yellow and falls from the plant. Purplish or brownish spots and streaks may appear on canes.
Pests & Diseases
Problem/Symptom