Knowledgebase

Apple scab #817126

Asked December 01, 2022, 3:03 PM EST

Our flowering crab hasn’t had apple scab for a few years do we stool to get it sprayed every year?

Hennepin County Minnesota

Expert Response

Hi Stella,

There is a typo in your question, I assume you’re asking if you still need to get the tree treated every year? It sounds like you’ve had someone spraying the tree with fungicides.

Some varieties of crabapple are susceptible to apple scab and may drop all their leaves in a bad year, while other types are barely affected. If your tree is susceptible and loses its leaves year after year, that eventually can weaken and kill the tree. Other types never get it.

Do you know what type of crabapple tree you have? Here’s a list of resistant varieties that should be fine without treatment:

  • 'Adams'
  • 'Adirondack'
  • 'Baskatong'
  • 'Bob White'
  • 'Candymint'
  • Coralburst
  • Christmas Holly™
  • 'David'
  • 'Donald Wyman'
  • Firebird
  • Harvest Gold
  • 'Indian Magic'
  • 'Indian Summer'
  • 'Jewelberry'
  • Lollipop
  • 'Louisa'
  • Molten Lava™
  • M. floribunda
  • M. halliana var. parkmanii
  • 'Prairie Maid'
  • 'Prairiefire'
  • 'Purple Prince'
  • Red Jewel™
  • 'Robinson'
  • 'Royal Beauty'
  • 'Tina'
  • 'Sargent'
  • 'Silver Moon'
  • 'Strawberry Parfait'
  • Malus x zumi
  • 'Calocarpa'

Scab can be linked to environmental conditions in summer, including warm rainy weather. Last year’s drought meant there wasn’t a lot of scab in many areas of the state. 

The best thing you can do to protect your tree is rake up all fallen leaves and dispose of them. Whether you spray is up to you. We never know what summer will be like.

Here’s more info on apple scab:

https://extension.umn.edu/plant-diseases/apple-scab#life-cycle-of-apple-scab-1165410

Good luck.

Mary Jane Smetanka Replied December 01, 2022, 4:09 PM EST

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