A really odd apple problem - FB can you help?

[Storming Norman]

Hi FB I see you are online,

Can you look at the enclosed photos of a apple problem I have spotted on my cooker.

The worst of the apples are with the RHS in Wisley, but they don't seem to know what is wrong right now.

These apples are quite lightly affected presently, but I'm really concerned as I really like this apple and the fruit would normally be ripe and ready to eat in August.

What has happened:

1. The apple tree is badly infected this year with woolly aphid - it is getting worse by the day. I just bought some spray but have not yet used it.
2. I pruned fairly heavily last winter [about 20% removed].
3. I start looking at the apples to see when they will be ripe [because I need to use a systemic spray] and see these blotches on the apples.
4. The blotches start as a small red blush, then a white circle appears in the red [which forms a ring], later the centre of the ring goes brown - the brown centred ones are at the RHS.
5. These apples have been picked they have not dropped and bruised.
6. The rings are on the part of the apple facing upwards to the light - not on the part touching the adjacent apples.

This has me foxed.

Can you tell me if it is self limiting or a more difficult issue and if the apples are still edible.

It is a 60 year old tree but still incredibly productive [and feeds many neigbours].

Thansk for your help,

Ann

[FB.]

Hmmm...
My guess would be something along the lines of a very bad case of bitter pit, or some other nutritional disorder.

If the tree was pruned hard last winter, it will be trying to re-grow what was lost. The new shoots will be competing with the fruit for water and nutrients, which means that the fruits are literally being starved by the competition for nutrients (calcium and water in particular) from the regrowth of branches.
If the weather has been unusually dry (it has been very hot and dry in my area this year and I'm concerned about several of mine potentially developing bitter pit), or even if the rainfall has been erratic (heavy one month, none the next), that puts stress on the developing fruits, if they're competing with the regrowth from pruning during the winter.

The tree should eventually get back into balance and the fruit damage should
reduce in the next year or two. I'd consider some summer pruning instead of winter pruning - if it was mine.

Have a look at the RHS "bitter pit" page here:
Royal Horticultural Society - Gardening Advice: Bitter Pit

.

[Storming Norman]

I see what you are saying - thanks by the way- however the more developed apple problems are not sunken patches but big round circular patches of 2" across and growing.

The reasons though are sound. I have heavily pruned for 2 years to catch up [I was unable due to injury to climb a ladder for a few years beforehand and it got right out of hand]. The tree is going mad putting on water sprouts and I have started a summer prune that you advised me to do a few months ago to control this very vigorous tree.

Seems a good water might do it some good - never done that before as it is so well established.

So should I thin off some more fruit? Should I take out the major branch I was going to take this winter now? will it affect all the fruit or just some?

Thanks for your help. Ann

[FB.]

Thinnig the fruit will make the situation worse.
Increasing water supply might do the same, if there is a sudden change in available water for the tree after months of drought.
I would get rid of all the upright "watersprouts" in the next few weeks.
I would also only prune in summer (July) for the next couple of seasons.
Maybe consider reducing nitrogen and increasing calcium - as per the RHS suggestion.

I appreciate that it doesn't look quite like bitter pit (and it might be something else - some kind of brown rot, but you'd expect an injury to allow the rot to set in), but much of the trees recent history fit the bill for being at high risk of bitter pit.

I think that the problem will be transient and that it is all related to the hard prune.

[FB.]

addition:

I would not remove "older" wood in summer - there's too much risk of canker setting in if you take out a large branch in summer.
The older branches ought to be taken out during the winter, but you'll probably aggravate the bitter pit as a result. Better to aggravate bitter pit for a year or two than to risk a large and nasty canker developing at the site of a large pruning cut that may eventually spread and kill the tree.
Summer pruning is only really intended for the soft shoots that haven't fully hardened-off. There's not much risk of canker being a problem if the soft shoots are pruned in July.

[Storming Norman]

Ok Thanks for that.

I found this site and this picture of sunburned fruit really looks familiar.

What do you think?

Two Types of Sunburn in Apple Caused by High Fruit Surface (Peel) Temperature

[ohbeary]

Now, this is not my field! but!!!, the one thing I do recall about "established" apple trees is that if it be a p'tickly dry year give your trees a bucket a week (2 1/2 - 3 gal)poured into a hole by the trunk, in these times of slightly warmer than normal conditions(global warming is bunk) I would up this amount, "if the ground around is dusty, water lusty" (voice of Stewie)"oh! I say, I do believe I've just coined a country saying" anyhoo I don't think you have bitter pit, sorry just being a busybody.

[rana]

If it is sunburn then global warming must have hit Surrey to get to temperatures of over 100F.

[Storming Norman]

100f is around 37c is that right? That's hot.

It has been hot though and it's been very tough to use the garden with the humidity as well.

The record set for June was 32c about 10 miles from here. It's the south facing part of the tree that seems to be affected. It's in a very sheltered in this part of my garden, that is why the fruit ripens so early for a cooker - it's often fully picked by mid/end August.

Perhaps this is not just a fanciful thought after all.........

Global warming eh? I've put an aubergine in the garden this year and it's fruiting - that has never happened before either.

[FB.]

Ok Thanks for that.

I found this site and this picture of sunburned fruit really looks familiar.

What do you think?

Two Types of Sunburn in Apple Caused by High Fruit Surface (Peel) Temperature

Well, sunburn was something that crossed my mind (especially as you mention on the sunny side of the tree), but I'm surprised that the tree hasn't suffered before. The summer of 2003 was a scorcher that killed my lawn. This year, at least some of my lawn might survive!
Perhaps the winter prune has exacerbated the problem that would not normally be detectable. I had to move my James Grieve (Scottish origin) apple a few years ago because it didn't perform well in a full-sun spot (I'm in a very hot part of the UK). I planted the JG in semi-shade under a large bush and the JG is now happier.

[Storming Norman]

Oh well if it is sunburn at least it will not be the whole crop and is not a deathly disease.

I think I will go for the spray on the woolly aphids to stop stressing the tree any further. It's like a snow storm pruning off the water shoots with all this aphid fluff.

Thanks FB - will let you know how it progresses.

Ann

I can't move the tree...............

[Storming Norman]

This was the email reply I got from the RHS today who have been considering this issue:

''Thank you for your apple sample. The symptoms on the fruit are strongly suggestive of sun scald. It is likely that this occurred during the extremely hot and sunny weather (now a distant memory!) of a few weeks ago. Sun scald often develops when the branches become weighed down by the fruit, so that apples that were previously shaded become exposed to the sun.''

Affected fruit should still be perfectly edible after cutting away the scorched tissues. One of your fruit was beginning to suffer from a secondary rot, where a fungus was beginning to colonise the damaged skin and flesh. Fruit affected in this way are probably best discarded.

So it is the sun - well if that is the case it will probably be the last of it I see for the year. Possibly taking off the water sprouts may not help, but thinning a bit more vigorously, and more pruning/training may prevent some of this happening again.

It could have been much worse..........