cdelei
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Posts: 2
Joined: Wed Jul 27, 2016 8:33 pm

Apple Tree Disease - Brown Spots on Leaves then Dies

I need help identifying what's going on with my dwarf apple tree. I have several of them in huge above-ground pots - two that are a few years old and a few that were only planted from bare root this spring. While working out of the country for a couple months, the person watching my house let me know the leaves on the new pink lady tree were starting to look like they had brown stains. The progression was curling and then the leaves would die. I asked her to move the tree away from the others but I was unable to provide proper treatment :cry:

I know I've lost the tree at this point, but I want to identify what this is. Our weather has been extremely warm since late spring. And very windy. I have one other new tree that is starting to show the same signs but hasn't progressed. I want to figure out what it is so I can treat it. In the meantime, I've also moved it away from the others. Is this a fire blight issue? I've never actually seen fire blight before. I'm in Southern CA. Any help or recommendations would be much appreciated!
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JONA
Mod
Posts: 803
Joined: Fri Jul 25, 2014 11:11 am
Location: Sussex. England

Re: Apple Tree Disease

Hi.,
Those cankers on the trunk and branches do look like Fire Blight damage.
But....usually it causes die back from the end of twigs, branches etc first.
The leaf damage that the pictures show look far more like severe powdery mildew infection.
So, what's to do?
First the cankers. Once they get as bad as that on a tree I think the end is inevitable. So any young tree with that level of canker I would remove and burn.
the other trees I would suggest keeping a spray programme going for mildew. So that new leaves are protected as they developed.
There is nothing you can do about the Fire Blight I'm afraid. Best control is removal of infected material.
John

cdelei
Newly Registered
Posts: 2
Joined: Wed Jul 27, 2016 8:33 pm

Re: Apple Tree Disease

Thanks John! I was having her spray for powdery mildew originally. It's pretty common in our area on the roses, squash plants, etc. But when I got back and saw the cankers, I had a feeling it was worse than mildew. I think between the two, there was just no way for this tree to recover. I'm keeping a close eye on the other affected tree. Looks like powdery mildew right now, which has gotten better. But I'll look for signs of fire blight since that may very well be coming. Thank goodness nothing else is showing signs (so far).

JONA
Mod
Posts: 803
Joined: Fri Jul 25, 2014 11:11 am
Location: Sussex. England

Re: Apple Tree Disease

cdelei wrote:Thanks John! I was having her spray for powdery mildew originally. It's pretty common in our area on the roses, squash plants, etc. But when I got back and saw the cankers, I had a feeling it was worse than mildew. I think between the two, there was just no way for this tree to recover. I'm keeping a close eye on the other affected tree. Looks like powdery mildew right now, which has gotten better. But I'll look for signs of fire blight since that may very well be coming. Thank goodness nothing else is showing signs (so far).
Just a further thing on mildew control.
Mildew on apples has two stages.
First is primary mildew which is the highly infectious stage and occurs when the flower buds are just opening on the trees. The whole fruit cluster is enveloped in the mildew and the cluster fails to develope properly. It helps control enormously if you can pick these clusters off and burn.
It is from this primary source that spores are left for the secondary mildew to develope. This is the mildew that infects leaves And shoots later in the season.
Again...you can see these infected shoots at pruning time, and should be cut off if possible as they will be a source in the spring for re- infection.
Bad infections of mildew can seriously reduce crop levels as well as damage the trees growth.
John

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