Recently our office has had many questions related to powdery mildew. What is powdery mildew? It is a disease caused by powdery mycelial and spore growth most commonly found on leaf surfaces but flowers, fruits and shoots can also be affected.
Powdery mildew is very prevalent in California’s dry summer weather. It may cause leaves to turn yellow, die and fall off. In addition, severely infected plants may have reduced yields, shortened production times, and fruit that has little flavor.
UC ANR has some great publications to help keep this from becoming a problem in your yard. Please see: Powdery mildew on vegetables: Pest notes for home and landscape.
Powdery mildew on ornamentals: Pest notes for the home and landscape or Powdery mildew on fruits and berries: Pest notes for home and landscape for further information.
Commercial growers can find information powdery mildew by crop at UC IPM’s pest management guideline site.
Powdery mildew on rose.
Underside of pepper leaf with patches
of powdery mildew.
Powdery mildew causes irregular
yellow blotches on tomato leaves.