WSU Extension

Hortsense

Plum, Prune (Fresh)
 
Disease
Armillaria root rot 
Bacterial canker 
Brown rot 
Crown gall 
Cytospora canker 
Plum pockets 
Russeting 
Shothole (Coryneum blight) 
Silver leaf 
Virus diseases 
Insect
Aphids 
Apple-and-thorn skeletonizer 
Brown marmorated stink bug 
Earwigs 
Fruittree leafroller 
Leafhoppers 
Pacific flatheaded borer 
Peach twig borer 
Peachtree borer 
Pear slug 
Scale insects 
Shothole borer 
Spider mites 
Spotted wing Drosophila (SWD) 



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Caption: Coryneum blight symptoms on leaves and fruit
Photo by: R.S. Byther
  
Plum, Prune (Fresh) : Shothole (Coryneum blight)
(revision date: 5/19/2015)


Biology
Coryneum blight is a fungal disease. Lesions on leaves are initially small, purplish, round to oval areas which expand into brown spots with light centers. The lesions are typically up to 1/4" in diameter. The infected spots on leaves often die and drop out in warm weather, giving leaves the characteristic "shothole" appearance of the disease. The fungus probably overwinters on the bark and in infected buds. Spores are easily spread by water.
Management Options

Non-Chemical Management
  • Prune and destroy dead buds and cankered twigs if present.
  • Rake and destroy infected leaves.
  • Avoid overhead watering.
Select non-chemical management options as your first choice!

Chemical Management

If fungicides are used as part of your management program, apply at 50% leaf fall in late autumn before heavy rains to protect leaf scars (except sulfur products). Chlorothalonil, IMMUNOX, or sulfur products can also be applied in spring when petals fall. NOTE: Bonide Fung-onil is for spring use only. Homeowners should not make foliar applications to trees over 10 ft tall. Consult a commercial pesticide applicator for treatment of trees and shrubs over 10 ft. tall.

Listed below are examples of pesticides that are legal in Washington. Always read and follow all label directions.
  • Bonide Fung-onil Multi-Purpose Fungicide Conc
    Active ingredient: chlorothalonil  |  EPA reg no: 60063-9-4
  • Bonide Sulfur Plant Fungicide Micronized Spray or Dust RTU [Organic]
    Active ingredient: sulfur  |  EPA reg no: 4-62
  • GardenTech Daconil Fungicide Conc
    Active ingredient: chlorothalonil  |  EPA reg no: 67572-82-71004
  • Hi-Yield Snake Eyes Dusting Wettable Sulfur
    Active ingredient: sulfur  |  EPA reg no: 7401-188-34911
  • Lilly Miller Sulfur Dust Fungicide/Insecticide Dust or Spray
    Active ingredient: sulfur  |  EPA reg no: 802-16
  • Ortho Max Garden Disease Control Conc
    Active ingredient: chlorothalonil  |  EPA reg no: 239-2522
  • Soap-Shield Flowable Liquid Copper Fungicide [Organic]
    Active ingredient: copper octanoate  |  EPA reg no: 67702-2-56872
  • Spectracide IMMUNOX Multi-Purpose Fungicide Spray Conc
    Active ingredient: myclobutanil  |  EPA reg no: 9688-123-8845
  • This list may not include all products registered for this use.
Images

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Caption: Coryneum blight symptoms on leaves and fruit
Photo by: R.S. Byther