Cox apple tree questions

[FB.]

.........the M-prefix rootstocks (apart from the mistakenly-named M116 which should have been named MM116) are too prone to woolly aphid in many areas..........

Following further study, I am now of the opinion that M116 was not incorrectly named, since I have become aware of a MM116 rootstock which once existed.

My current evidence suggests that they are different.

MM116 was part of the Malling-Merton series of rootstocks, bred around 1930 from Northern Spy x M2.
Vigour is similar to MM111 and M2 (around 80% of full size; vigorous half-standard or standard tree, around 4m in average conditions).

M116 was bred from MM106xM27 in the early 1960's under the name AR-86-1-25 and renamed M116 after trials.
Vigour is similar to M7 and MM106 (around 65% of full size; semi-vigorous bush or half-standard tree, around 3m in average conditions).

It is even possible that MM116 became M25, since:

1. Data for MM116 ends around the time M25 was rejected from the MM101-115 series for insufficient resistance to woolly aphid. It's almost as if M25 takes over from the point where MM116 disappears.

2. M25 was also bred from Northern Spy x M2.

This now leaves me wondering which "M116/MM116" rootstock I have (or are they M25?) because I obtained my so-called M116 via someone who had imported some (since M116 is/was so difficult to find in the UK).
But did my supplier ask for M116 or MM116?

My suspicion is that I have M116 (formerly AR-86-1-25).

[Feral007]

FB - you're really trying to confuse me now

Just popped in to say that my apple trees are all going well atm. The two near the house - Granny Smith and Pink Lady have heaps of fruit on them (as opposed to last year when they had about 4 fruit and 3 dropped off!) The granny smith seems to have some small dents in the skin which I'm not sure about. We haven't had hail that I can remember, and there are no holes in them just a dent.
The parrots have been checking them out. 3 apples half eater - nope not ready yet, we'll be back! One small branch broken off as the parrot was obviously too heavy for it. Or else it was a cockatoo - they will sit on a branch and then just snip it off next to their foot. I've left the chewed fruit on, in the hopes they will leave the rest for me!
The two Cox's Orange Pippin trees out the back have done better than I expected. They were about 4-6 weeks leafing up, than the other ones near the house. But now they have nice green leaves. Not too many, but very healthy looking. One is incorporated into a little garden and the other is 'stand alone' atm. It's been very dry and windy and they haven't had quite as much watering as I'd have liked since I've been busy trying to keep on top of everything. But they seem to be managing which is good.

Of course, it is the 18 mth/2 yr mark that can be the death knell around here - when they hit rock. I'm hoping by then we will have the wind breaks, the mulching plants and plenty of semi shade for them. Dream on

[FB.]

The granny smith seems to have some small dents in the skin which I'm not sure about.

Bitter pit?

Which rootstock(s) are you using?

[FB.]

Of course, it is the 18 mth/2 yr mark that can be the death knell around here - when they hit rock. I'm hoping by then we will have the wind breaks, the mulching plants and plenty of semi shade for them.

MM111......MM111......MM111......MM111

It has good vigour and is one of the most disease-resistant and drought-tolerant apple rootstocks available. Once established, it will carry on growing and cropping much better than most other rootstocks during droughts.

Failing that, see if you can find MM109 or M16 as they're very vigorous and also drought-resistant.
MM109 has a tendency to lean, while M16 is a lighter cropper than most other rootstocks (but better to have a light crop than to have no crop or a dead tree!). MM109 is resistant to the troublesome woolly aphids but M16 is susceptible.
Northern Spy is available "Down Under" as a rootstock and is medium vigour and also fairly drought-resistant and resistant to woolly aphids.
The dwarf M9 is also fairly drought-resistant for a dwarf, but is not resistant to woolly aphids. It might be easier to keep a small tree well-watered than a bigger tree.

[Feral007]

LOL FB! You have no idea how hard it is to get them to give you even a clue what the rootstock is! Let alone give you a choice of them!

Now that you are teaching me all the finer details I can start to look around and see if I can find places that actually tell you.

I've just had another tree (Chinese Pistachio) turn it's toes up beginning of this season. Very annoying. All the ones out the front of the house have done that eventually.
Hoping the side of the house, and the back area will have better luck.

Yes, it does seem Bitter Pit is the culprit - I had a google after you mentioned it. Probably because of the horribly dry patch we've just been through. Will have to make sure I stay on top of that next year. I have a plan for those two trees next year, and it might just work.

[FB.]

I've just had another tree (Chinese Pistachio) turn it's toes up beginning of this season. Very annoying. All the ones out the front of the house have done that eventually.

What kind of soil do the trees need, and what kind of soil do you have?
Is your soil too acid, too alkaline, or deficient in an essential nutrient?
Is there a pest or disease affecting the trees - perhaps an underground bug or grub eating the roots?
Is the nursery where you're buying the trees harbouring a disease which attacks those trees and the trees bring it with them? It's quite surprising how many plants of all types bring disease from the nursery.

Bitter Pit is the culprit - I had a google after you mentioned it. Probably because of the horribly dry patch we've just been through. Will have to make sure I stay on top of that next year. I have a plan for those two trees next year, and it might just work.

Again, it might be something to do with the soil pH or nutrient levels.
It might also be due to the (unknown) rootstock not being able to cope with the soil. When the going gets tough, it's very important to know which rootstock you have, so you can choose one that is the most suitable.
For me (I also have a relatively infertile soil and low rainfall), many of the dwarf and semi-dwarf rootstocks just don't have the strength in their roots to provide all the nutritional needs of the fruit - so I get bitter pit a lot too. I get much less - almost none - when using the most vigorous rootstocks. The soil is so poor that vigorous rootstocks behave like semi-dwarfs and only reach half their potential.
There is also strong evidence that in less fertile and drier soils, the vigorous rootstocks also outcrop the dwarfs.
I've regularly suggested that I think I could produce more fruit at an earlier age and of better quality on the vigorous M25 than on the darf M9. Bitter pit is often a big problem for me on M9 or MM106, but is not a problem when grown on the stronger M25 roots.

[Feral007]

I know FB, but I've already got these trees in the ground so just working with what I've got atm.
When I'm getting some more for the back fruit n nut forest I'll be looking at rootstock first!

I think it's just been a really dry season this year. We had some good rain and we thought yaay, but then there was absolutely nothing after that. Been one of those years where you never get time to do everything so the trees were too dry, and it seems that even if there is enough calcium in the ground the lack of water will stop it going to the fruit.

All I can say is.......well at least I've got some green leaves!

It really does seem that the plants can bear the freezing cold in the winter, but it's the dry heat in summer that knocks them off. The chinese pistachio tho, not sure the dogs didn't knock it around. But it just had a huge split in it at ground level. Just totally split. The rest of the plant looked fine!