Xanthomonas fragariae

Angular leaf spot


Xanthomonas fragariae is a leaf spot disease found in strawberry.

Life cycle and appearance of Angular leaf spot

Xanthomonas fragariae overwinters in plants and dead leaves, that become the primary source of infection in the spring. The bacteria are also introduced in a crop in new transplants. This bacterium is very resistant to desiccation and can survive well in dry leaves or leaves in the soil, but not independantly in the soil. Under humid conditions, bacteria ooze from the lesions on the leaves and form a secondary source of infection. They are dispersed by rain, irrigation water or handling of the plants. Infection of the plants happens both passively and actively. Infection and disease development are favoured by temperatures around 20 °C during the day and cold nights, in combination with high humidity or presence of water. These conditions occur mostly in the spring if it rains or when sprinkler irrigation is used. Healthy, well growing plants are more susceptible than diseased or stressed plants.

How to prevent Angular leaf spot

  • Use clean propagation material and disease-free seed
  • Remove sources of inoculum such as dead leaves
  • In field-grown tomato and pepper, rotate fields to prevent infection from volunteer plants and crop debris
  • Avoid waste piles in the vicinity of the greenhouse or field
  • Resistant cultivars of pepper are available and should be used

Prevent plant diseases by optimizing plant potential and crop resilience.