For those of you who don’t know, I’ve had a community garden for a little over a year now, and this is a picture of one of the apple trees left behind by a previous gardener. There are several apple trees, but this is the nicest and most productive, especially given it’s small size.
The trunk however has some kind of strange rot which appears to be threatening to kill the tree. While I might be able to cut the tree back to the healthy branch on the right, that wouldn’t leave me with much of tree and there’s no guarantee the rot wouldn’t come back. For the moment there are lots of apples forming on the rotten part of the tree.
Does anyone know anything about this rot, what causes it and if there is anything I can do about it? I’ve seen a local nursery offer apple trees resistant to ‘apple tree cancer’ (a literal translation from Dutch that may be something different in English), is this the problem here? Do I just need a resistant variety? Is it some kind of fungal problem? Would grafting a scion from this tree on to different root stock solve the problem?
Your apple tree problem brought out the old master gardener in me – I didn’t know what the problem was right off, but I wanted to find out! I went to the spot where I nearly always start when researching a garden problem – UC IPM Online, the University of California pest managment website. From what I read there and then doing a google image search I’m wondering if your apple problem could be Nectria galligena – European Canker, a fungal disease. Here’s the UC website about it: http://www.ipm.ucdavis.edu/PMG/GARDEN/FRUIT/DISEASE/europeancanker.html
Looks very much like apple canker (Nectria galligena/Neonectria galligena). It is an fungal disease located in the area of the wounds. When it eventually gets around the trunk of your little tree it will be fatal for that part of your tree, but the healthy branch can go on living for many years. It is rather slowly progressing. I have it in one of my appletrees, in a spot where my appletrees always seems to get this disease.
The good thing is, that a little appletree like yours react on the infection by increasing the appleproduction, until it has no more energy to produce apples.
What about the white stuff? Would that be part of the canker or is it a moss or lichen growing on the wounded tissue? I tried to find pictures as well but didn’t see anything that quite matched. Good luck Patrick!
Patrick,
this is indeed cancer. It’s not really very bad right now, but things can get worse. What you can do is cut the sick parts away, using a sharp knife, and use some (organic) tree paste to cover the wounds. Just don’t cut over half the diametre of the branch.
This is not a 100 % reliable solution, but in many cases it works, lots depends on the global health of the tree. I’ll try and take a few pictures one of these days on how to do it, and send them shortly.I have some branches that need a bit of treatment as well.
Thanks everyone!
The Dutch word for cancer is canker (or kanker), so it seems the English name for this tree disease is borrowed from Dutch. I guess there was no need to translate it…
Jo: From the pictures Michelle linked to, I would guess the white stuff is the dormant fungal infection. We’ve had a long hot and dry period, and the article mentions this is only active in cool wet periods. It’s actually a little green in color, and does sort of look like moss or lichen, so I’m not sure really.
It’s really interesting to hear everyone’s ideas of the best way to treat it! It seems like there’s not one clear answer.
If Frank agrees, I’ll make a post from the pictures he sends. His approach sounds like a good one, and I’ll probably give it a try too. Now I need to find some tree paste…
Awesome Patrick. We have a few apple trees and with your help, we will keep them healthy! Nobody told me ANY of this stuff in kindergarten… =o)
Hi, I’ve had similar cankers to this on a few of my apples & wasn’t sure if it was European canker or fireblight canker …..I’ve cut it out completely, most of the time. But when that wasn’t possible (Young tree & the canker was low….near the graft union) I opted to leave it & see if it would heal itself. I just brushed a DILUTE copper solution (it prevents bacterial growth, as well as fungal growth) over the stem on & around the canker. I repeated this a few times after rain. The tree healed itself & bark gradually grew back around the stem. I can’t say if the copper treatments did the trick or if it would have healed without my help. But I figured I had nothing to lose, I couldn’t cut below the diseased section or I’d be down to rootstock. Copper is available at any garden centre & it’s quite cheap. I use it at “green tip” to prevent fireblight on my susceptible apples & pears..that’s how I got the idea to try this. Has anyone else tried this????
Hi Nancy,
Thanks for stopping by and leaving the comment! I’m really learning a lot about fruit trees this year, and I really appreciate all the input.
I have a question when is the best time to spray apple trees for bugs
Hi Alice,
I’m an organic gardener and don’t usually spray my plants with anything. With apple trees you can use horticultural oil, which some people consider organic, and should be applied in early spring as the trees start budding.
If you’re using something besides this oil, I’m afraid I have no idea when you should spray it.