Cankers and Diebacks With One Common Suspect: Botryosphaeria

1. Fungal bodies on twigs (black dots), 2. leaf spot close-up with fungal bodies, 3. canker on twig, 4. fungal spres
Botryosphaeria fungus can cause blister-like structures under the bark of twigs, bark sloughing, cankers, leaf drop, diebacks and fruit rots on tree fruits.

Many species of the fungal organism Botryosphaeria were found on most of the woody plant samples we received in the Plant & Insect Diagnostic Clinic this year. These fungi belong to a family of pathogens (capable of causing disease) and endophytes (present in the tissue but dormant) capable of living and causing disease in woody tissues such twig, branches, and fruits.
 These fungal pathogens infect about 200 different hosts including broadleaf trees, woody ornamentals and conifers. Symptoms vary by host plant but can include blister-like structures under the bark of twigs, bark sloughing, cankers, leaf drop, diebacks and fruit rots on tree fruits.
 These fungal pathogens have the ability to colonize and live in plant tissues while causing disease only after the onset of environmental stress. Severe infection can follow drought, wounds, or freezing damage, and may occur on non-native plants or plant outside of their recommended range or USDA zone.
 
What can you do to prevent this disease from affecting your plants?

  • Properly install (plant) and care for new plants, especially during the first year.  Promote tree vigor by proper mulching and irrigation during dry periods.  In most cases, fertilizer is not needed.  See  "Community Tree Planting and Care Guide" (HORT 3054).

What can you do after your plant was diagnosed with Botryosphaeria?

 

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Authors: 

Lina Rodriguez Salamanca Extension Plant Pathologist and Diagnostician

Dr. Lina Rodriguez-Salamanca is an extension plant pathologist and diagnostician with the Iowa State University Plant and Insect Diagnostic Clinic  (clinic.ipm.iastate.edu), a member of the National Plant Diagnostic Network (NPDN,&nbsp...

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