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Strawberry Powdery mildew

Leaves curl upward and have a white powder on the leaf underside.

Powdery mildew grows on the undersides of leaves, causing them to curl upwards. Often a whitish “powder” can be seen on the undersides of leaves.

Strawberry leaf underside that is mostly obscured by a white, powdery coating. There is a cluster of several small black splotches growing in the white powder.
Leaves curl upwards due to powdery mildew.

In severe cases, the fungus may cover the upper surface of the leaves as well. Occasionally, the edges of leaves turn reddish purple.

White powder growing on upper side of strawberry leaves. Leaves are curled upwards.

The disease is spread to new leaves by airborne spores called conidia.

Microscopic image showing a green, sticklike rod with several white circles attached to it. The white circles resemble soap bubbles and are relatively uniform in size.
Powdery mildew conidia.

Later in the season (August – September), small black fruiting bodies (cleistothecia) may be visible on the leaf lower surface. The fungus oberwinters as cleistothecia on dead leaves.

Microscopic image of dark brown and black spheres on underside of strawberry leaf. Spheres appear to be attached to bottom of leaf, and do not have visible stem. Spheres somewhat resemble insect eggs or frass (insect poop).
Powdery mildew fruiting bodies on strawberry leaf underside; microscopic view.

In some instances, the fungus may infect the fruit stems…

Cluster of strawberry fruit with distinct, powdery white discoloration on fruit stems.

…or fruit itself.

Unripe, white strawberry fruit with white powdery growth visible on seeds and flesh surrounding seeds.

The most susceptible strawberry variety grown in the Northeast is ‘Earliglow’, but day-neutral varieties are susceptible as well.

A first year planting of ‘Jewel’ strawberry heavily infected in early July.

Field of strawberries with leaves curled upwards.

Group of strawberry plants with leaves curled upwards.

More strawberry powdery mildew information:

Use these resources if you need additional help with diagnosis and to find solutions to your problem.