Apple Disease Pictures (Canker/Mildew/Scab/WAA)

[FB.]

tamsin

You don't mention the variety, but it's probably scab. I'll see if I can add some pictures of unusual manifestations of scab attack in a little while.

In the second picture, the fat bud at the tip of the pruned twig looks like a flower bud for next year. There also may be another fruit bud in the background.
It's possible that your tree has gone biennial, or that poor pollination was the problem. Mine were not well pollinated this year, due to lack of bees.
If your tree has slipped into biennial bearing and it's small enough to get around, you can break off some of the fat, furry buds before they open next year. The crop will be lighter as a result, but it won't be biennial.

[seasprout]

FB, i'm gonna start calling you Dr Apple.

Thanks for advice on other thread of mine about Apple Bountiful, supplier has exactly want I want, and I recieved their catalogue today.

[peanut]

I think that many of the popular (shop) apple varieties are more prone to disease because everyone want to grow them and therefore the specific strains of scab that attack GD (or Cox, or other varieties) are quite numerous across the UK. Growing more unusual varieties with a reputation for disease resistance can be beneficial.
I grow several russets and although they get moderate leaf scab, the fruits are rarely affected. They also resist mildew and canker quite well, too. Although GD has good resistance to mildew and adequate resistance to canker.
My own GD usually has much worse scab on the leaves than the fruit. It doesn't have many fruits this year, but the fruits have almost no scab, whereas the leaves are quite tatty. But leaf scab doesn't bother me too much.

Have you considered re-grafting your GD? If it has a good root system established, why not make good use of it.
Bear in mind that GD is a very good pollinator for many apples, since it has a very different set of incompatibility genes to most British varieties. Getting rid of the GD may affect pollination of your Cox. I believe that Cox has incompatibility genes 5 & 9 and GD has 2 & 3 - meaning that their is absolutely no genetic factors to block pollination.
If, for example, you grew Kidd's Orange Red instead of your GD, it has the same 5 & 9 incompatibility genes as Cox, so is completely unable to pollinate Cox due to the Cox thinking that the 5 & 9 pollen of Kidd's is from the Cox (apples don't like their own pollen, or pollen that resembles their own).

How about keeping your GD as a severely restricted form such as a cordon, fan or espalier?
The better sunlight penetration and the easier air circulation in and around a cordon allows the fruit to dry faster after rainfall. It also allows better size, colour and taste of the fruit.

edit:
I see that you're in Cambridgshire. If you plan to have a go at re-grafting your GD, I may have some suitable piecies of scion wood during the winter. My apple trees don't grow much, so I don't need to prune all of them every year, but I'll definitely have to prune some of them and you would be welcome to some scion wood - although for about £13, you could buy a new tree from Simpsons Fruit Tree Nursery at Fordham and choose from their good selection.

Thanks FB for such brilliant help!

My GD is only in it's second yr of planting, it was just a young tree from Adli I think. In the first yr it had it half a dozen fruit, this yr it's laden with them but the fruits are totally decimated by Scab....such a shame.

My neighbour has an orchard so pollination should be fine.

I think i may give up on the GD before i get attached to it and search out a local variety maybe.....any suggestions?

Many thanks for your help.

[tamsin]

Thanks I'm not sure what variety it is, it's a smallish eating apple.

I didn't realise apple trees could switch schedule! That sounds most likely as, if I remember right, it only had one bunch of blossom so nothing for the bees to pollinate if they were there. I just popped out for a good look and it does have one apple.

[FB.]

Some more pictures of the various presentations of scab...

A few small scab spots:



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A few small scab spots on the leaf:



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Scab damage at the edge of a leaf:



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Numerous small scab spots:



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[FB.]

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A couple of very large red-brown damaged areas on these leaves. Also notice many small whitish dots on all the leaves visible in the picture - which I believe represent scab attacks that were stopped by the plants defences.



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A cluster of russet fruits (free from scab), with surrounding leaves variably damaged by scab.

[FB.]

.....and in this picture (same picture as above), I have circled a variety of the obvious signs of scab. They are showing as large areas of brown, through to variable sizes of spots, through to tiny pinpoint specks. There are several other areas or specks that I haven't highlighted because the picture was getting messy.

[tamsin]

Yes, it looks a lot like that last one. The leaves have a few spots on but most of the damage is around the edges/end.

I checked with my mum (she planted it) and she says it's a cox's orange pippin. It's a small tree about 6-7' tall and about the same across.

How would we go about treating it?

Would scab effect the apple crop or is that two seperate issues?

Thanks!

[FB.]

Thanks FB for such brilliant help!

My GD is only in it's second yr of planting, it was just a young tree from Adli I think. In the first yr it had it half a dozen fruit, this yr it's laden with them but the fruits are totally decimated by Scab....such a shame.

My neighbour has an orchard so pollination should be fine.

I think i may give up on the GD before i get attached to it and search out a local variety maybe.....any suggestions?

Many thanks for your help.

Maybe the nearby orchard is the source of the scab.

There aren't many apples form this area, but some local-ish apples that I've seen for sale in Cambs nurseries include:

Chivers Delight
Red Ellison
Early Victoria
Sturmer Pippin
St.Edmunds Pippin
Many of the Laxton apples are from Bedfordshire

I hear that Chivers delight suffers from canker.
Red Ellison suffers from canker.
Don't know much about Early Vic.
I hear that Sturmer pippin suffers from mildew, but has moderate resistance to scab.
Don't know much about St.Ed's
Most of the Laxton apples have one or more disease issues; Laxton Superb easily gets fruit scab.


If I had to choose just one variety for good disease resistance and good cropping in this area, I'd shorlist:

Tydeman's Late Orange (a strong grower)
Crawley Beauty (a slow grower and needs a very late flowering partner)
D'Arcy Spice (an extremely slow grower and partial tip bearer)
Egremont Russet (sometimes affected by bitter pit)

You could also try one of GD's offspring; the modern "Saturn".
It has many fruit similarities with GD but the fruits are a bit more colourful.
Saturn was the result of a complicated breeding program that included scab-immune apple varieties and Golden Delicious.
The result is an easy-eater with a bit more colour than GD and a lot more scab resistance.

Personally, I'd opt for a russet (I actually have several russets) because I believe that the skins are semi-porous and tend to soak up some of the water after heavy rain. The fruits therefore dry quicker and give fungal spores less time to attack. You can see precisely that in the above picture of Egremont Russet - woith scabby leaves but healthy fruits.

[FB.]

Yes, it looks a lot like that last one. The leaves have a few spots on but most of the damage is around the edges/end.

I checked with my mum (she planted it) and she says it's a cox's orange pippin. It's a small tree about 6-7' tall and about the same across.

How would we go about treating it?

Would scab effect the apple crop or is that two seperate issues?

Thanks!

Treatment would involve spraying at least several times per year - and more in bad years.
Ensuring that the branches and leaves are not crowded will help air circulation and sun penetration - which will dry the fruits quicker after rain.
Scab requires the leaf or fruit surface to be wet for several hours consecutive. Good light and air circulation can dry the fruit before the scab spores have completed their several-hour germination period.
As leaves and fruits mature during the growing season, they become more resistant to scab. The worst scab damage tends to be caused when the fruits suffer a prolonged wet period when they are cherry sized.

Both fruit and leaves can be attacked by scab. Sometimes the fruit splits and is ruined (like my Laxton Superb this year - the whole crop is ruined ). Somtimes the fruit just gets spots. You can eat the scabby fruits after removing the scabbed and split bits - assuming that the wasps havent taken advantage of the split fruit.

[carrotcruncher]

Canker - what to do?

Hi FB,

Many thanks for sharing your extensive apple tree knowledge

I've moved to a house with 5 apple trees and a pear tree in the back garden, all of which have been neglected. I don't know the ages of the trees but I would say they are over 20 years, there used to be a orchard here before the houses were built in the 70s so could be even older!

From your photos I can see there is a lot of canker in some of the trees, even on some of the larger branches, although they are bearing lots of fruit this year. Whats the best way to treat this, is removal of the infected bits the only answer?

Also, the branches from the trees tangle in with each other. From what you say, this is not good for diseases etc, so........... Whats the best course of action?

Should I go for major pruning in one go to remove crossing branches but expect little fruit next year, would the shock be too much?

Or should I prune them gradually over a couple of years?

When's the best time to prune?

Thanks in advance for any advice, I'd hate to kill them off by doing the wrong thing!

Carrotcruncher

[FB.]

The cankers can be dealt with by pruning off the affected branches, or by cutting out just the area of the canker. It depends on where and how big.
Remove cankers and do any other pruning work after the tree has dropped it's leaves. Don't remove more than about a quarter of the tree in any winter.
Renovation of the trees will take a few years.
Older (neglected) trees can be a nightmare to deal with all the canker and they may just have to "live with it".

For the first winter, I'd go for cutting out all the dead twigs/branches, followed by cutting out or pruning-off the cankers.
Then, if you haven't already removed a quarter of their wood, start removing the worst of the congested/tangled/rubbing/overlapping/badly placed branches.
Next summer, the tree may produce lots of vigorous upright shoots in response. Cut off all but a few well-placed of those upright shoots in mid-July.

In following winters, gradually thin-out the congested/diseased branches, making sure not to remove more than 1/4 of the tree each winter. Continue removing all green upright shoots in mid-July.

The whole renovation will take 2-4 years.......but if they're fruiting well, it may be better just to leave them alone as much as possible and only cut out the cankers.

Some varieties are reasonably able to fight off the canker, or the progress of the canker is very slow. In other varieties, canker is very damaging. I have an Ellison's Orange and it's a canker-magnet and the cankers grow rapidly, so that it needs cankers removing every winter. Some of my others also had cankers at some point, but the cankers were fought-off and eventually just left a scar on the bark.

[BUFFS]

Apple scab

What is the best way to contrl scab,we had a house fire last year so the garden was unavoidably neglected,this year most of the apple trees have scab ,some quite bad..so in need of all the expert knowledge you can throw at me,i am missing my egrmont russets.......thanks as i threw them away as they seem to also have bitter pit.

[FB.]

This year started well, but then turned damp, so scab has yet again been a problem.
The best way to fight scab (and other diseases) is to grow varieties with strong natural resistance.
You can try spraying, but it would require at least several sprays during the season. I'm not a fan of spraying.
You can also try raking up and burning the fallen leaves. The problem is that you can't get them all and you can't stop scab spores blowing in the wind and landing on your trees.

You mention

"....missing Egremont Russets..."

What do you mean by that? Egremont Russets (and other "old" russets) usually have good resistance to fruit scab, although they can suffer from leaf scab.

[FB.]

Ah! The Russets have bitter pit.

Things that can cause or worsen bitter pit:

Erratic rainfall (lots of rain one month and none the next).
Not many apples on the tree.
Young or vigorous tree.
Too much feeding (especially nitrogen).
Hard winter pruning.