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Black spot is caused by a fungus, Diplocarpon rosae. Hybrid tea roses are the hardest hit by the fungus, although all types of roses may be infected. Leaf spots are the most characteristic symptoms. The black spots are round with feathered edges and are up to 1/2 inch across. Spots are mostly on the upper surface of the leaf and often have a yellow halo around them. Lower leaves usually become infected first. The optimum weather conditions for disease development are 75°85°F with high relative humidity or rainy periods.

• Ornamentals
  • Shrubs
  • Floriculture