How to Manage Pests

Pests in Gardens and Landscapes

Stamen blight—Haplosphaeria deformans

Flowers infected with stamen blight are white and powdery. Infected flowers may appear larger than healthy flowers as their stamens are flattened against the petals and sepals; the stamens of healthy flowers are in a ring around the stigmas. Anthers become be discolored and swollen. Fruit tends to be small and hard to pick.


Stamen blight, caused by the fungus Haplosphaeria deformans, can be spread by wind, rain, bees, or even mechanical means. Use disease-free plants and remove any wild blackberries or raspberries from the area as they can provide a source for the disease. The alternate-year fruiting system may also help to provide control of this disease, reducing any source of inoculum.

Statewide IPM Program, Agriculture and Natural Resources, University of California
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Agriculture and Natural Resources, University of California

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