Pear tree diagnosis

[chrisdb]

Hi all,
One of my young pear trees has been (so far) non-fatally sick for the last couple of years and I'm struggling to diagnose the problem(s) accurately. I would like to think that all symptoms spring from one underlying problem, but I suspect it actually has multiple things wrong with it.

The other thing to bear in mind is that there is another pear nearby (about 5m away) which has also been in for a few years and so far shown no symptoms.

Here's a list of the symptoms. The first one is easy:

1. The red spots and growths under the leaves later in the season that I am 100% certain is Pear Rust. I don't think anything else common has the same colour and odd growths.

The next two I do not think can be symptoms of pear rust:

2. The first leaves of spring will grow as normal, but later leaves, including leaves on new growth, will tend to develop black bits on the edges and then curl. The leaves do not die back completely or fall off - they stay until the autumn, but distorted in shape. Since the first leaves of the season are generally OK, what you end up with is a healthier looking core of the tree with all the distorted leaves on the ends of the shoots and branches.

I haven't read about this being a possible symptom of pear rust, so I think it must be indicative of another pest or disease.

Pear leaf midge is a possible diagnosis for this, but I've never found any of the larvae, despite looking and flattening out some of the distorted leaves.

I don't think it's pear leaf blister mite as the development and placement (only on leaf edges) isn't consistent.

I don't think it's fireblight as blossom is unaffected and the shoots and branches don't die back. Also, symptoms don't occur on leaves from buds that showed symptoms in the previous year, since the symptoms always occur near the new growth.

2. Starting this year, several deep splits have developed in the bark directly below where some of the main branches emerge from the trunk. The splits are V-shaped and only underneath where some of the branches leave the trunk.

This is more worrying, obviously, than something attacking the leaves. To me, the shape and appearance of the splits doesn't look right for canker. It looks more like extremely uneven growth - like the branches have tried to grow too fast and split open the bark underneath them.

As discussed above, I'm doubtful that fireblight is the right diagnosis as the flowers look completely normal and then is no die-back further up the branches.

I am leaning towards tree stress being the likely explanation. The tree is in a very well drained spot in the garden, and this past year had quite prolonged dry spells in the summer. It seems possible that a combination of water stress (despite some watering on my part when I was in the country) and being attacked by a couple of different diseases is the cause of the bark splitting.

So my guess is:

1. leaf disorders
(i) pear rust
(ii) ??? - unknown other problem, could be pear leaf midge, but no larvae found despite checking both years
2. bark splitting due to tree stress caused by:
(i) very well drained site, not optimal for quince rootstock
(ii) other diseases / pests

The final question is whether it's worth just getting rid or not. I have a couple of extra trees coming this winter, an apple and a pear, so I could rip out this particular pear tree and put the new apple in its place (or in a new hole 1 - 2m away). Obviously an apple isn't an ideal replacement since it's part of the same family, but it's what I have.

I am not a huge fan of keeping trees that need constant chemical spraying to survive, so what are the chances of some non-chemical TLC (e.g. mulching around the base to increase moisture retention) helping enough for it to recover?

[bearded bloke]

2. Possibly potash deficiency ? Do you feed the tree at all ?



EDIT : have a look here .......... https://www.lovethegarden.com/advice...ash-deficiency

[roitelet]

Sounds like pear rust. I would gather up all the fallen leaves and burn them and give the tree a good soaking of Bordeaux mixture and then give it another year to see what happens.

[boundtothesoil]

I think your 'stress' hypothesis is probable with regard to the blackened leaf margins. Could be wind or water, or both. I've frequently noticed wind damage to young expanding pear leaves, resulting in blackened edges. I imagine that what actually kills the tissues in these cases is dehydration of the young cells around the edge of the leaf (exposed to the greatest effective air speed and the greatest turbulence, maximising water loss), as they will not be able to control the loss of water by transpiration as effectively as mature leaf cells can, either through their stomata or directly through the surrounding immature cell walls. I could easily be wrong though. A prolonged period of drought stress could also result in a similar effect.

Most years my mature conference pear trees have pretty ropy looking leaves, but they produce fruit reasonably well. Despite significant leaf damage, what functional leaf area remains supports sufficient photosynthesis for the tree. If it were me, I wouldn't give up on the tree.

[Guest]

You sound like like you are already have a fair idea what is going on. Pear rust, stress and possible pest attack. I would give it a year. Although it is not something I usually do, but if I think it will give a bit of a head start I would give the tree a winter wash,then feed and mulch.

[chrisdb]

Thanks for all your comments! Since it doesn't seem like I've missed anything, I'm leaning towards giving it another year as you say. A winter wash sounds like a good idea as well.

beaded bloke: It's a possibility, although the tree seems to flower normally and potash deficiency normally means reduced flowering. The other odd thing if it is a nutrient deficiency is that another pear tree of the same age, in similar conditions around 5m away, isn't showing any symptoms. The main difference between the two is the variety (Beth vs Concorde).

I dug in a lot of manure, compost etc. when I planted it but I haven't actively fed it for the last couple of years. Since my plan if I keep it is to mulch around the base anyway, I will add some fertiliser at the same time. I have a big pile of rotting comfrey (I think that's high potash) that I could relocate under the tree, plus some manure, and whatever else I can acquire from the local garden centre.

[chrisdb]

Most years my mature conference pear trees have pretty ropy looking leaves, but they produce fruit reasonably well. Despite significant leaf damage, what functional leaf area remains supports sufficient photosynthesis for the tree. If it were me, I wouldn't give up on the tree.

Hi - yes, it's impossible to have untouched leaves if you don't spray anyway. There's always something munching on something, or attacking something. The thing that worried me more is the splitting of the bark - but if the cause is stress rather than something else, perhaps with enough TLC the tree will manage to make a start on healing them next year.

If on the other hand the splits get even worse even with some extra pampering, I think it's curtains.

[Guest]

^^^could the split bark not be due to erratic growth.

Also the tree with the issues...is it the concorde? My concorde is not a good specimen, but I do wonder if the variety as far as the trees are concerned might not be the best/strongest.

[chrisdb]

Yes, it's the Concorde that has all the problems. The Beth so far has been more or less bomb proof - very slow growing, but doesn't seem to be troubled by much in the way of pests or diseases.

[Jay22]

After a few years I have at long last got fruitlets on my pear tree BUT...I have just discovered little white insects on the underside of the leaves causing them to curl. Any idea what it is? I've sprayed the tree really hard with water but until I know what it is I can't do anything else.

[Snoop Puss]

Two of my pear trees suffer from black, wilting branch tips most years. They usually develop after very cold or windy conditions. I simply remove them. I wouldn't give up on the tree because of this.

[Jay22]

Any idea what the beasties are? Small and white in curled up leaf?

[Jungle Jane]

Any idea what the beasties are? Small and white in curled up leaf?

It sounds like aphids,are there ants on the tree too? Aphids cause a bit of leaf browning & curling,I noticed an ant on my pear tree the other day but didn't notice any aphids yet. I should've put Vaseline around the base of the trunk but I never worry they don't eat the fruit & can be managed with a lot of squirting with water/soap/garlic clove concoction when the suns gone down. If you can manage them,they don't cause the leaves too much harm at all & all the fruit will be alright.

[Jay22]

Thanks JJ, just been out and had a real good look...its aphids! Will apply the soap method, hopefully that will keep them under control. Are the ants attracted by something the aphids do?

[Jungle Jane]

Yes the ants like the honeydew they excrete. Ants protect the aphids from ladybirds,there's a photo online of ants biting at a ladybirds leg,I hate ants now!