How to Manage Pests

UC Pest Management Guidelines


Strawberry Leaf Blotch

Pathogen: Zythia fragariae

(Reviewed 6/08, updated 6/08)

In this Guideline:


Strawberry leaf blotch is most often found early in the season following heavy rainfall. Symptoms consist of tan to grey lesions that quickly expand from the leaf margins on the first few leaves of the new plant. The lesions, which most often begin at leaflet margins, can grow to cover a quarter to half of the leaflet surface. The presence of very small black to brown fruiting bodies inside the lesions is an important sign of this disease. This pathogen can also cause black to brown lesions on the petiole, as well as a brown blight of the calyx and decay on the calyx end of the strawberry fruit.


Zythia fragariae is dependent on splashing water for spread of inoculum, and the disease is therefore much more common in winter and early spring. This pathogen survives on strawberry residue in the soil and most likely will not persist in the absence of this residue.


Leaf blotch has been a minor problem in California, and strawberry plants grow out of this disease when the winter rains stop. Fungicide applications are not recommended.


[UC Peer Reviewed]

UC IPM Pest Management Guidelines: Strawberry
UC ANR Publication 3468


  • S. T. Koike, UC Cooperative Extension Monterey County
  • G. T. Browne, USDA Crops Pathology and Genetics, UC Davis
  • T. R. Gordon, Plant Pathology, UC Davis
Acknowledgment for contributions to Diseases:
  • W. D. Gubler, Plant Pathology, UC Davis

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