Apple scab. If you do not intend eating the crab apples then spray with a systemic fungicide. Collect up and fallen fruit and leaves and dispose of them.

Thanks for that OB...I was interested. Can you please say a bit more...is it a common problem? Will it recur? Will Lourenco be having to spray regularly? Or is it fairly easy to get rid of this disease. anything we can do to prevent it recurring? Sorry.....lots of questions, but it does look a dreadful mess...and I have apple trees too!

It is a very common problem on certain kinds of Apple and Pear and proper Quince. In fact it is common on all members of the Rose family, just in others it is called Black spot rather than Scab.
Some forms are more resistant than others. To a certain extent it is weather dependent, hot and dry makes it worse.
It is not that easy to get rid of. I spray our less resistant types with Copper sulphate (not keen on eating fruit with systemic fungicide in it),and that sort of controls it, but it is still there.
Keeping the tree open by proper pruning so air can circulate certainly does help.

Thanks very much!
Do you know the name of a product that contains copper sulphate and is readily available at most garden centres?

The only source of Copper sulphate that I can find is...............Copper sulphate. I am told that the only place you can buy it now is from Home Wine Making Outlets. I have enough stored to last me about 2 years, after that..................?

Thanks owdboggy! That's really helpful! :))

If its a sort of black spot would Roseclear do the trick?

O
Enough copper sulphate stored for two years, or wine?
W

Lol....both would be best I think! :))

Sadly I am unable to drink alcohol any more (developed an allergy to it and I get the hangover while I am still drinking even a small glass).
Roseclear probably would help, but I do not grow roses and so have no personal knowledge of it. One could but try and report back.
I do have a Systemic fungicide which I have used on our Quince as it has no fruit (again!) and I will let you know how successful that is.

Roseclear has systhane...not sure...but it helps with roses anyway!