Cherry Leaf Spot

Cherry leaf spot (Blumeriella jaapii) is one of the most serious diseases of ornamental cherries in the landscape. The disease mainly affects the leaves, but lesions may also appear on fruit, petioles and fruit stems (pedicels). Diseased leaves drop prematurely, and severely affected trees may be defoliated by mid-summer. Early and repeated defoliation can result in a decline in vigor, which combined with buried root collars, girdling roots, and poorly drained soils can lead to premature decline.

Susceptible Hosts

Ornamental flowering cherries (Prunus spp). Common cultivars:

  • Yoshino
  • Kwanzan
  • Okame
  • Autamnalis

Signs of Damage

  • Small circular purple spots appear on the upper surface of the leaf in spring
  • Spots gradually enlarge to about ¼ inch in diameter and turn reddish-brown
  • Centers of the spots may dry up and drop out, giving a “shot-hole” appearance
  • With heavy infection older infected leaves turn yellow and eventually drop

Physical Appearance

  • Lesions may emerge to produce large, irregular spots. will be microscopic
  • Whitish-pink masses of sticky spores (conidia) form within the spots on the undersides of infected leaves during periods of damp weather

Purple spots and early shot hole appearance

Biology / Lifecycle

  • The fungus overwinters in dead leaves on the ground. In early spring (about petal fall), fungal fruiting bodies called apothecia develop in these leaves
  • Spores (ascospores) discharged during rainy periods for about six to eight weeks
  • Small purple spots soon appear on the upper surface
  • Under damp conditions and with temperatures between 60 and 68 degrees F (15 and 20 degrees C), lesions may appear in five days
  • Once lesions have developed, masses of secondary or summer spores (conidia) are formed, causing new infection under ideal temperature and wetness conditions

Late season defoliation

Treatment Strategy / Expectations

Collect and destroy the fallen cherry leaves in late autumn. The fungus overwinters in these leaves.

Select a planting sight that is always exposed to direct sunlight, has good air circulation, and soil drainage. Proper pruning to open the canopy will increase sunlight penetration and air circulation. Any practice that promotes faster drying of leaves will reduce the risk of infection.

This disease can be controlled with fungicide sprays.

Product App. Method Dosage Timing Re-Treatment

Foliar Spray

4-6 oz/100 gallons water

Apply at bud break

2-3 times on 14-day intervals

Foliar Spray

1 3/8 pints/100 gallon water

Apply at bud break

2-3 times on 14-day intervals

Foliar Spray

20 fl oz/100 gallon water

Apply at bud break

2-3 times on 14-day intervals

Soil drench or soil injection

Refer to Cambistat rare card

Whenever the ground is not frozen or saturated with water.

Every three years

*Product is Rainbow Ecoscience’s industry standard recommendation for most industry situations.
**Cambistat is a plant growth regulator that induces a disease resistance response in trees.

Foliar Spray Using Myclotect*

Foliar Spray Using Pegasus 6L

Foliar Spray Using Talaris 4.5F

Soil Drench/Injection Using Cambistat**

Foliar spray with Maruyama

Soil Application with HTI 2000


Always refer to product label for rates and approved uses. Some images courtesy of forestryimages.org or Wikimedia Commons. Use of the images does not imply endorsement of treatments.

A Treatment Guide is designed to help you identify common issues and management solutions. Comprehensive Treatment Guide PDFs, which include current products, application rates, and additional information, are available upon request.