I've inherited an apple tree growing in heavily polluted ground (tailings and spoil from copper/tin mining).

The tree is fruiting with nice sweet cooking fruit, but is absolutely covered in lichen and what appears to be a fungal infection.

Diseased apple tree

Close up of possible apple canker disease

This doesn't look like apple canker to me, I've not seen these big galls before, but I've only seen relatively new apple canker infections. I suppose the tree could grow over the canker year on year to create these protrusions?

So is this an apple canker, and if not does anyone know what it could be? I'm in Cornwall, UK if that helps.

I don't have much hope of treating it as it's so systemic, but I want to know how careful I should be to prevent transmission to other trees.

Thanks for your help!

  • I don’t think it is fungus but woolly aphids. Not sure what caused the galls. Sep 5, 2022 at 11:14

1 Answer 1


This is the damage as done by woolly apple aphids. These aphids suck tree saps from your apple tree, and by doing so cause these deformations.

The deformations themselves are usually not a big issue, but the damaged bast can cause a tree to get infected by canker, which is a fungi. You should see red swellings and general distress of the tree (brown and small leafs, less growth).

Apple canker is not caused due to polluted soil, although I won't help either. Please make sure to not eat the apples from this tree though, since they might be poisoned.

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