Bud loss on an apple tree

[waterfall]

A five year old apple suffered last year and this from an insect that rolls up the new leaves and nibbles through the stem of the new shoots. This means few fruit again - very disappointing.

What is it and what can be done without using chemicals (or if only chemicals will work which one works best with least side effects).

A younger tree and another really old one are loaded with fruit and seem not to be affected - why might this be?

[ginger ninger]

I've had the same problem waterfall. It sounds like the "leaf curl midge", but I'm able to squish the bugs by hand as my apple tree is a dwarf. Have a look at this site...it might be able to help you.

If it were just the bud I'd have said it was birds, although the bird might cause damage getting to the larvae of the midge.

[waterfall]

Thanks for the link. The photo shows exactly the damage caused but when a leaf is unrolled there is either nothing inside or only one green/black caterpillar less than 1 cm in length. Not the multiple red/orange ones mentioned. Unfortunately this tree is not a dwarf and getting at all the buds is not possible. I shall try a grease band but if it is a fly that lays eggs this won't help. Don't think it is bird damage but we do have many species around.

[FB.]

Lack of fruit is unlikely to be due to damage to the new stems.
Most of the leaves on the new stems are fuelling the growth of those stems. Only the leaves at the older part of the stem will be fuelling fruits or roots.
It is the "rosette" of leaves at the base of an apple spur that are dedicated to fuelling the fruits.

My guess is that:

1.
The tree is not mature, so wants to grow and not fruit. If the soil is too fertile (or the tree too well-fed) it will grow and not fruit.
Vigorously growing trees produce few fruits and those which are produced will be small, poorly flavoured, prone to drop early and often suffering from bitter pit.
Unless it is a dwarf, it will not fruit well until it is several years old. Some varieties take much longer to come into cropping (you don't mention variety or rootstock or soil quality).

2.
Pollination was poor.

3.
Blossoms were damaged by excessive cold or hot weather.

4.
The tree is biennial or erratic cropping.

5.
You have pruned off its flower buds (is it a tip bearer?)

[waterfall]

Thanks Cropper, I will try and answer your points.

1. Tree cropped well in year three and would have done in year two if I had not pinched out most of the fruits to encourage what was left to get bigger.

2. Pollination on the two other apple trees mentioned seems to have been fine

3. ditto the weather was the same for all three trees

4. The variety (Rein de Reinette) is well known locally and crops annually in local orchards

5. Hope I didn't but it fruits along the length of the branches normally.

Still pretty sure it is insect damage from examination of the buds I can get at (it is about four metres tall) as it is the rosette of new leaves that gets nibbled off/damaged.

[FB.]

Regarding weather:
Some varieties' are much more sensitive to weather than others.
Many of my regular croppers set no fruit this year, despite prolific blossom and plenty of bees. On the other hand, some of my normally-less-reliable croppers are groaning under the heavy weight of fruit.


Regarding fruiting in the first year or two:
In the early years, the trees are stressed after planting.
Stressed trees produce fruit in response to thinking that they're going to die in such situations. Of course, they don't die; it's just transplant shock.

Did the tree actually flower much this spring, or is it not flowering?
Lack of blossom and rapid growth is a sign of an over-vigorous tree.

If your tree has managed 4 metres in five years, it sounds as if either you have exceptional soil quality, or you've been over-feeding, or the scion/rootstock is abnormally vigorous.

The problem sounds like your tree is too vigorous and it doesn't want to crop well until it reaches whatever final size is its destiny - do you know which rootstock the tree is grafted onto?

My guess is that your tree is on a non-size-controlling "heavy standard" rootstock, normally reserved for use in traditional orchards, for growing trees with a 1.5-2 metre clear trunk and a spread of 6-10 metres.
Vigorous young trees - especially when on strong rootstocks - will not produce much blossom, or not set much fruit, or drop fruits.

I really doubt that insect damage to the tips of the stems is the problem; I think that excessive vigour is the problem.
Can you post a picture of the damaged stems and also a picture of the fruit spurs, to see their condition?

[waterfall]

Hope these help. One last thought could it be aphids and the maggot/caterpillar the larva of a fly seeking a food source for it's young?

[FB.]

The damage may be apple twig cutter in the first picture and aphids in the second, but there is still more than enough new growth to power any fruits (if they were present).
The insect damage is opportunistic because of the plentiful growth. A symptom of an over-vigorous tree providing plentiful feeding sites for pests, rather than pests being the cause of a non-fruiting tree.

The tree is too vigorous to want to crop. Just look at the length of the new growth and look at its height and trunk girth compared to its companions behind: all of its resources are going into new shoots, rather than fruiting. That energy can easily be diverted for cropping next year, but only if you really want to listen, rather than keep blaming the insects.
No amount of pest control will make it fruit because pests are not the cause of the problem.
Even if you spray it with every insecticide known to man; it won't make it fruit (but will be a great waste of your time and money).
You may well find that relieving it of the pest burden will energise it even more and only make it grow even faster and take even longer to start cropping.
The problem is excess vigour, due to either:

Rich soil, overfeeding or it's grafted onto vigorous rootstock

As I said earlier: do you know the rootstock of the tree (and its companions)?

...........

[waterfall]

No I'm sorry I don't know the rootstock and your comparison with the other trees in the picture is misleading as it's companions are a damson planted two years ago and a nectarine. The other two apple trees are out of shot.

The tree is not fed and never has been, the soil is sandy with some clay and not particularly fertile. It has grown well but not particularly more than others planted at the same time eg a plum and the nectarine. That I am not convinced the problem is over-vigorous growth is not due to not listening but to observation over the five years it has been in my garden. It was about one and a half metres when planted.

Don't forget prior to the last two seasons this tree fruited well and even this year there is some fruit. That's why I still think it is some form of insect damage. Your point that it is attractive to pests is correct as there were many fruit buds that seemed to be being damaged by the same maggot caterpillar that inhabited the rolled up leaves. Was that apple twig cutter? Did something else cause the rolled up leaves? Could birds cause the damage getting at the pests?

[FB.]

OK, on the assumption that it's pest damage.....

Bullfinches and other small birds will strip the fruit buds on some varieties.

There are apple blossom weevils and winter moth caterpillars which can damage blossoms.

There are codling moth larvae and apple sawfly larvae which can damage young fruits by tunnelling and eating-out the pips, therefore causing the fruit to drop.

If, as you say, the same variety is extensively grown nearby, there will be a reservoir of pests and diseases which have become accustomed to attacking the older trees of the same type - "developed a taste for them" so to speak. It is not unusual to see a less common variety almost trouble-free while common varieties are much troubled by pests migrating from comemrcial orchards or nearby gardens.
I grow a handful of very rare, old, forgotten varieties and they are virtually free from all pests and diseases.

[FB.]

......as for what to do with your existing tree.....

If it is outgrowing its companions, I would carry out some fairly hard pruning of the soft young shoots during July, which should stimulate extra blossom formation for next year and reduce the growth rate.

If there is no objection to its size, I'd leave it as it is, apart from the winter pruning to direct the trees shape.
As the tree matures, it will produce ever-greater amounts of blossom and there will be enough for the pests to take their share and still leave enough for a good crop. It may also be the case that the tree is drawing attention away from its companions - a sacrificial plant, so to speak.
I retain an Ellison's Orange and Scrumptious, which do a great job of attracting all the codling maggots. I rarely get any decent fruit from those two, but my other apples seem to suffer only minor damage in most years, presumably because the maggots were drawn away. If you've ever tasted a properly-ripened Ellison's Orange or Scrumptious, you'd understand why the pests like them.

[waterfall]

Googling the pests you mentioned especially winter moth caterpillars produced photos showing similar damage and the timing of their activity fits as well. Seems likely this is at least one of the causes so a grease band should help and spraying in the spring. I'll try that anyway and thanks for your help.