Entyloma belongs to the smut fungi.

Also known as:
Dahlia smut (dahlia)

recognize entyloma on leaves
Celandine leaf affected by entyloma, photo: Björn S - CC BY-SA 2.0

Entyloma belongs to the smut fungi. Smut spot on dahlias is caused by Entyloma dahliae, one of 180 species of this smut fungus. Entyloma dahliae causes blue-green spots on leaves; the spots turn brown and dry out from the center.
Entyloma begins as pale spots on the lower leaves during cool, wet periods with heavy rainfall. Light to dark brown spots appear in the middle of the grayish spots. As the fungus matures, spores appear on the surface of the spots. This fungus spreads only under moist, cool conditions. This smut fungus can also infect sunflowers, gaillardia and calendula – both in the garden and in the greenhouse.
Entyloma overwinters in the soil and can infect healthy tubers via infected soil that comes along with the dug-up tubers.

Where to find

  • Dahlia
  • Marigold (Calendula)
  • Gaillardia
  • Sunflower


Remove and destroy the affected foliage. Fungicides are used in professional floriculture to prevent further infections.


Provide adequate sunlight and air around the plants. During cool periods, do not pour water on the leaves, but on the ground.
Ensure open foliage when greenhouse growing and good air circulation. Irrigate the soil in the greenhouse instead of pouring.
When digging up the tubers, knock away soil that comes along with them.