Powdery Mildew on Fruits and Berries

Sphaerotheca spp.

Identification and damage
Powdery mildew can be recognized easily on most plants by the white to gray powdery mycelium and spore growth that forms on both sides of leaves, sometimes on flowers and fruit, and on shoots.

The disease can be serious on woody plants such as grapevines, caneberries, and fruit trees where it attacks new growth including buds, shoots, and flowers as well as leaves. New growth is dwarfed, distorted, and covered with a white, powdery growth. On apple and grape and to a lesser extent apricot, nectarine, and peach, infected young fruits develop weblike, russetted scars. On tree fruits a rough corky spot on the skin will develop where infection occurred. Grapes with a severe infection may also crack or split and fail to grow and expand.

On strawberry, affected leaf edges curl upward. Infected leaves later develop dry, brownish patches along with nondescript patches of white powdery fungus on the lower surface and reddish discoloration on the upper surface. When foliage infections are severe, flowers and fruit may also be infected.

Plant Protection Products