WSU Extension

Hortsense

Rose
 
Disease
Black mold 
Black spot 
Botrytis bud and twig blight 
Brand canker 
Bullheading (cold damage) 
Common canker 
Crown gall 
Downy mildew 
Powdery mildew 
Rust 
Viruses 
Insect
Leafcutting bees 
Leafrollers 
Redhumped caterpillar 
Root weevils 
Rose aphids 
Rose galls 
Rose leafhopper 
Rose midge 
Roseslug 
Spider mites 
Thrips 
Tobacco budworm 
Western spotted cucumber beetle 



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Caption: Botrytis on rose blossom
Photo by: R.S. Byther
  
Rose : Botrytis bud and twig blight
(revision date: 4/22/2015)


Biology
Botrytis can infect stems and flowers, including stubs left from pruning or flower removal. Infected tissues are usually covered with a fuzzy, gray-brown growth. Infected flower buds may not open, and can show sunken, smooth, grayish spots on the bud and flower stem. Sunken, dead areas may develop on the canes. Infection is worst during cool, wet weather.
Management Options


Non-Chemical Management
  • Remove all infected portions of plants as soon as the first symptoms appear. This reduces spread of the disease.
  • Clean up and destroy all dead plant materials.
  • Increase air circulation in plantings by proper spacing and pruning.
  • Avoid overhead watering.
Select non-chemical management options as your first choice!

Chemical Management

Use as a foliar spray, but focus on cultural controls.

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 Infuse Systemic Disease Control Lawn & Landscape
    Active ingredient: thiophanate methyl  |  EPA reg no: 53883-183-4
  • GardenTech Daconil Fungicide Conc
    Active ingredient: chlorothalonil  |  EPA reg no: 67572-82-71004
  • Ortho Max Garden Disease Control Conc
    Active ingredient: chlorothalonil  |  EPA reg no: 239-2522
  • This list may not include all products registered for this use.
Images

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Caption: Botrytis on rose blossom
Photo by: R.S. Byther
Caption: Botrytis on rose canes
Photo by: R.S. Byther