I would like to identify a desease on my apple tree

Looks like botrytis John.

A very common disease for many plants and vegetables. Botrytis is first noticeable as browny yellow spots, which are followed by a furry grey mould. The cause of the disease is too much dampness in cool conditions - growing plants in over-fertile conditions also encourages botrytis.

Remove the conditions which caused the disease in the first place. Avoid over-watering and ensure that the plant or seedling has plenty of air circulating - if the plant is congested with growth, prune away some of the growth (especially in the centre of the plant) to permit air to circulate. Reduce the amount of fertiliser being applied.

All infected growth should be removed and burned - do not put it on the compost heap. Where the garden pest botrytis persists, spray with Copper Fungicide (Bordeaux mixture) which is safer for you and garden life than most other chemical sprays available in garden centres.

Dear Sarraceniac,
Thank for this very quick response to my question. As you probably see already, I am no gardener. The soil on Hayling Island is clay and seems very fertile. It is always very damp through the winter (particulalry at the moment) and then baking hard in summer. when sun is out it gets very hot in my garden. I have never fed any fertiliser to the tree!
Strong southerly winds (sea air - 500 yds from beach) prevail and so plenty of air. Unfortunately, there are small patches of the growth all over the tree which is on dwarf root stock. I think I will try the spray you recommend to start with and see what happens.
Very many thaks again
Sincere regards
John B

Sorry to disagree, but I am not sure that this IS botrytis. The yellow is lichen for a start and though it may harbour pests it is not a major problem.
The white stuff? Well first of all is it 'fluffy' like cotton wool? In which case it is Woolly aphid (possibly). Scrape a patch off and see ifyou can see the insect inside it. The cure is to spray the tree as soon as possible with a horticultural soft soap sold as Winter Wash for fruit trees. It is organic by the way. Even if not aphids it will do the tree no harm and some good to be sprayed. It kills of overwintering bugs from the bark crevices.
Another nethod is to scrub them off with warm soapy water. The wool is wax and soap dissolves it and the insect dehydrates.
You can even use a pressure spray to remove them, as long as the pressure is not to high and damages the bark.

Thanks Owdboggy.
I checked out your suggestion and found a really useful website about lichens: - http://www.countrysideinfo.co.uk/fungi/lichens.htm
I am sure you are correct and will be doing as you suggest as soon as I get a winter wash first thing tomorrow morning.
I was made redundant last year and now decided to go into early retirement and spend time in my garden. I think I will be a pest in this forum until my knowledge base on gardening increases.
Sncere thanks
John B

the yellow is definitely a lichen and there are a range of types. some are powdery some leafy and some wooly. if you are in a clean air area it is more likely to be lichen rather than fungal disease.

you are the type of pest we seem to like john.:o)

Lichen growth can mean that the plant is not vigorous and doesn't have enough leaves to shade out the lichen growth. Try feeding the tree in Spring to spur it into growth. A good feed will also help it to fight off any bugs.

lichen doesnt do any harm to the tree, and some species grow in very shady areas. but a winterwash probably would harm the lichen. depends if you like this very complex 'plant'.

Thank you Seaburngirl.
If lichen do no harm and will not affect the tree, leaves or apples in any way, then I will happliy leave well alone. I don't find the growth offensive in any way, my only concern was for the health of the tree.
What should I feed the tree with & when, to promote growth? (looking at volunteers comments)
Thanks for you comments
Sincerely
John B

Use a general purpose fertiliser anytime now. Check RHS page on feeding apple trees for more complex feeding. But really a small handful of fertiliser all around the base and then a mulch will be fine.

I would say that if the grey stuff is like a wooly wrapping then just try to wipe it off and if r fingers are coloured reddish brown from the little bugs that you have just squashed then its woolly aphid and you need to cut away which ever branch has it and destroy them... not composting . The tree will try to protect itself and little bulges will appear on the branches. trouble is that no matter how much spraying or grease banding you do if its well established its best to get rid of the tree and start again.. bit drastic but the tree will produce less fruit as it struggles to fight te aphid off.ou may find ants running up and down it as well and the ants are milking the aphids. So only use my suggestion when all else has failed.!

A bit drastic that advice. We have cleared our trees of wooly aphids by power washing with horticultural soap and they have not returned for the last three years.
Agree about ants 'milking' aphids though not usually wooly aphids. We stop them by making the grease bands flare out, like little ballet skirts and keeping the grease good and sticky!