Disease on my Cox's Orange Pippin apple tree?

[chippytea]

Hi all,

I've had a Cox's Orange Pippin apple tree in my garden for ages, always produces loads of fruit (too much!!) but this year I've noticed the apples are a bit 'spotty', and there's this on the bark which I'd not noticed before (my fault for not paying more attention to it).

Any advice? I'd hate to get rid of the tree as it's a nice centrepiece in my otherwise sparse garden, but I really don't know anything about tree diseases and thought you would be the right people to ask

Cheers!

Ben

[FB.]

Woolly aphid damage. In among the lumps and knobbles you'll find white fluff which covered greyish coloured aphids which "bleed" red if you squash them.
Their feeding damages the bark and sapflow vessels, leading to knobbly swellings, brittle wood and split bark - the damage then making it easier for the aphids to continue feeding and to hide from predators.

The damage that has already been done is not reversible and will probably become more knobbly, gnarly and swollen as the tree ages. The splits in the bark can be an entry point for canker, although there is no obvious signs of canker.

I am against spraying because of the serious risk to beneficial insects such as bees, but the woolly aphids can be blasted off with a hosepipe or can be gently scrubbed off with a brush (soapy water will quicken the drowing/suffocation of the aphids).

Once a tree is colonised it can be hard to clear it completely because the little devils could be hiding almost anywhere. Some varieties of apple are more susceptible (and some are resistant), and some rootstocks offer some resistance. Cox is about average susceptibility.

[FB.]

Some varieties also produce this kind of appearance due to "burr knots" which are knobbles on the bark which will root reasonably successfully if cuttings are taken when the leaves are falling.

Of course, burr knots can be an entry point for woolly aphids or canker too, since it is a split in the bark which is open to infection and the lumps and bumps provide good shelter for woolly aphids.