Pear tree diagnosis - could this be canker or scab?

[Pirahna]

Hi,

Over the next couple of years I hope to be able to down-size a pear tree in my garden. Over the past few years I have removed two large (approx 7ft) bushes which were growing within a couple of feet of the pear, and removed some miss-shaped and wrongly headed branches, but the tree is still suffering from scab and pear midge.

Hopefully by reducing the height of the tree, and removing the final miss-placed branches, I will be able to start effectively treating the scab/midge and again have a productive tree.

But..... before I plan the cuts needed I need some help in working out whether the tree also has canker! On two of the biggest upright branches there are these:



At the moment the plan is to cut above these, but if they are canker then obviously I will need to change the plan and cut below....

In both cases the damaged area appears to be dry - there is no sign of weeping, fungal growth, or anything like that. I've been keeping an eye on them for the past 9mths or so... but nothing like that has appeared and the damage is not growing.

Thanks in advance for any help/suggestions!

[boundtothesoil]

Difficult to say. Could be canker that has been successfully localised/controlled by the tree. But the left hand photo looks a bit like someone's had a go with a small axe at some time in the past.
Either way if the foliage above the damaged area is normal and there are no signs of any small branches blackened and dead, then I'd probably risk leaving them be.

[FB.]

Looks like canker that managed to get into a wound on the bark, but it looks as if it's been there for at least a couple of years and if so it's probably not too aggressive.
I think the tree has a good chance of healing it by itself (yes, trees can self-heal; some more than others).
Certainly hacking off a great lump of the tree with all its leaves on in mid-summer is going to be more of a shock to the tree than the canker itself. Major pruning needs to be done in the winter when the tree is dormant, otherwise there's severe shock from of losing all the resources that were put into those leaves.
Canker is less active in winter (it's too cold for its spores to germinate in wounds) but very active during the growing season - especially autumn when there are lots of leaf scars. So if you make a large pruning cut now it'll almost certainly get infected by canker again, not to mention shock the tree due to leaf loss as mentioned above.

So I would do nothing at the moment but I would look at the tree again about once per month through to winter to see how much the canker has changed (my guess is it probably won't have changed much). I might still do nothing at that time if the canker hasn't progressed because its position would result in severe deformity of the tree shape. An overall picture of the tree would be helpful to see how badly its shape would be affected if the cankered piece is removed.

[Pirahna]

`Thanks. If I can work out how to attach the piccies of the whole tree I will!

I was intending to leave the big cuts until winter, but it will probably need some summer pruning in the next month or so and I want to try and make sure I don't remove anything then which I might regret later!

[Pirahna]

OK. Two piccies (hopefully!) attached





As you can see the tree is quite lopsided - I think it was trying to escape from the bushes which had been planted around it! The two potential areas of canker/scab are both on the nice upright trunk - roughly at the same height as (and just above) the hanging bird feeder.

My guess is that the tree has been neglected (rather than miss-treated) since the day it was planted. When we moved in there was another main 'trunk' heading off across the garden - at about 1.2m above the ground and making the tree even more lopsided - which I removed. I also removed some wayward branches higher up.

The tree has responded really well - it looks much happier and suffers much less from scab. It may never become a pretty tree, or correspond to our beliefs of what a tree should look like, but as long as it continues to respond well to my efforts I'm willing to give it garden room

[Pirahna]

Looking at those piccies I should probably add that there is an apple tree behind the pear in the first piccie. The pear extends roughly to above the left hand side of the steps in the background. The rest of the greenery is the heights of the apple tree!

[FB.]

The tree does have the look of one that's been neglected. It will not be easy to make it into an ideal fruit tree because it is tall and straggly with very little growth at medium height.

You're left with a few choices - probably number 3 is most suitable:

1. Prune out the cankered bit in winter and have an ugly tree afterwards which might eventually bother you and persuade you to remove the tree and replace with a nicer looking one.
2. Remove the tree and replace with one that isn't diseased and which you will prune and care for properly so that it is attractive, healthy and productive.
3. Leave the cankered bit to keep a nicer tree shape and hope that the canker doesn't get any worse; if it worsens you'll lose the tree but will be able to start again with a new tree*.

*
When re-planting it is best not to plant the same variety in the same spot because the new tree will soon become infected with all the pests and diseases that affected the old tree. A different variety/rootstock combination might be OK in or near the same spot (e.g. replace a Williams pear on Quince A with a Conference pear on Pyrodwarf), or a different type of tree (e.g. replace a Williams pear on Quince A with a Beauty of Bath apple on MM106).

[Pirahna]

Thanks,

Choice 3 is what I was hoping for, but my experience of fruit tree illness is limited to what I've found in this garden - so I could have been working on a lost cause!