Growing fruit trees - Organic vs Un-treated

[FB.]

....We have found it slightly prone to mildew....

Any disease weakness will eventually be its undoing in a spray-free situation.

A tree well-suited to spray-free (or even to a breeding programme for disease resistance) must have no weak points at all, because, sooner or later, the variable British Weather will punish it.

I my area, where the weather is typically mild, low-rainfall but humid and with fairly infertile and low-moisture-retaining soil, powdery mildew is a severe problem.

I had to abandon Suntan, Empire and a few others because mildew destroyed them. For me, mildew is as bad as canker is for growers in wet regions because it incorporates itself into the wood to re-emerge next season - and it can overwhelm a susceptible tree in one or two seasons, and kill it within 2-3 seasons.

Many book writers dismiss mildew (and woolly aphids) but of all the pests and diseases, they are the most likely to keep me awake at night worrying how to deal with them.

The "MM" series rootstocks such as MM106 and MM111 were derived from the original Malling "M" series, but developed specifically for resistance to woolly aphid.

The MM rootstocks have resistance (but not immunity) to woolly aphid - inherited from Northern Spy which was crossed with the original M series.
However, the over-use of MM and Spy is leading to an increase in "Spy-capable" woolly aphids which have overcome the Spy and MM resistance.
Also a susceptible scion on an MM rootstock will still be somewhat susceptible to woolly aphids as it is the rootstock piece which has the resistance; not the scion. This helps prevent woolly aphids from "hiding" underground, but the above-ground parts of the tree can (and probably will) still be attacked.

[orangepippin]

Any disease weakness will eventually be its undoing in a spray-free situation.

All apple varieties and all rootstock combinations have disease weaknesses, but pest and disease pressures vary across the country, and from year to year. Mildew can be under-estimated, but on the other hand it is a problem more prevalent in drier areas / drier summers. Scab-resistance is perceived as the more serious problem and hence tends to be the focus of research, both in Europe and the USA.

I think Honeycrisp is likely to be amongst the most disease-resistant of varieties in the UK for some time - but no variety can ever be 100% resistant.

Also, in the context of a garden or community orchard, where outright production of "class 1" fruit is not the main objective, the inevitable losses from diseases, pests, accidents are not usually a big issue - they are a small price to pay for the pleasure of growing your own fruit. (But let's hope this season is better than 2012!).

[FB.]

I think Honeycrisp is likely to be amongst the most disease-resistant of varieties in the UK for some time - but no variety can ever be 100% resistant.

I think it would read better as:

"...Honeycrisp is likely to be amongst the preferred scab-resistant of varieties in the UK for some time...."

But without mildew resistance, it's of little use to me in my unsprayed situation - and may not perform well in gardens in the drier parts of the UK.

You can't call it "disease resistant" if it has a weakness. Disease resistant implies trouble-free. You should probably call it "one of the best scab-resistant" which is a more accurate description from what you've said of the variety.

[FB.]

All apple varieties and all rootstock combinations have disease weaknesses

In my experience, the following have no significant disease weakness (pests being a different issue which would shorten the list, also may be less resistant in their "home" countries):

Alfriston
Annie Elizabeth
ArdCairn Russet
Ashmead's Kernel
Barnack Beauty
Beauty of Bath
Belle de Boskoop
Brownlees Russet
Coeur de Boeuf
Colonel Vaughan
Court Pendu Plat
Crawley Beauty
D'Arcy Spice
Discovery
Edward VII
Gascoyne's Scarlet
Gladstone
Golden Harvey
Grenadier
Hambledon Deux Ans
Irish Peach
Jupiter
Norfolk Beefing
Reverend Wilks
Rosemary Russet
Scrumptious
Winter Gem
Winter Majetin

I would be happy to pit any of the above in a spray-free "semi-neglect" trial, against Honeycrisp. I suspect that mildew would sufficiently de-vigorate Honeycrisp that it would have no energy left to crop - maybe even kill it.

[orangepippin]

You can't call it "disease resistant" if it has a weakness. Disease resistant implies trouble-free. You should probably call it "one of the best scab-resistant" which is a more accurate description from what you've said of the variety.

I think there is a difference between "disease-resistant" and "no weaknesses" - and no apple variety is disease-proof and therefore all have weaknesses. As I think I've mentioned before, Honeycrisp, along with Rajka, was one of the few to provide a clean crop in the difficult conditions of last season, so for me at least that probably qualifies it as disease-resistant. It is perhaps best to think of it as "disease-resistant for the majority of growers the majority of the time".

Also, I don't think disease-resistant implies trouble-free. A trouble-free variety is one that is not prone to birds / codling moth / aphids, grows in a regular shape, is easy to pollinate or self-fertile, is happy on a range of soils, does not need much pruning, grows with good branch angles which are strong enough to bear the weight of crops, produces a high proportion of good quality clean apples - (I could go on) - as well as being resistant to a range of common diseases. And even then you have to take climate and location into account, because I think you and I would probably put Spartan in the "trouble-free" category, but growers in the wetter south-west might not agree.

[yummersetter]

If we're talking trouble free, you left out 'unpleasant tasting to rabbits, deer, goats, sheep, mice, badgers, squirrels and half the rest of Noah's ark'. I think four leggers are the biggest problem for a lot of people, way above any disease.

[FB.]

Going further along the "pest resistant" and "disease resistant" we could also add desirable characteristics of tolerating a wide range of soil types (deep, shallow, fertile, depleted, acid, neutral, alkaline), a wide range of climate types (long season, short season, warm summers, cool summers, mild winters, bitter winters etc) and an ideal habit of growth for minimum pruning requirement.

Many of the M and MM rootstocks fall down on the "soil and climate tolerance".

Many UK apple cultivars are too cold-tender to grow in some countries, or too heat-sensitive, or unsuitable winter-chill requirements. In my climate, some varieties known for doing well in Scotland can suffer from sunburn.

[boundtothesoil]

If we're talking trouble free, you left out 'unpleasant tasting to rabbits, deer, goats, sheep, mice, badgers, squirrels and half the rest of Noah's ark'. I think four leggers are the biggest problem for a lot of people, way above any disease.

Grey squirrels stripped the entire largish crop from my mature George Cave tree (MM106) last year but didn't touch the equally good crop on the adjacent Beauty of Bath. Strange.

[boundtothesoil]

Honeycrisp is probably the most popular orchard apple variety in the US at the moment. It has a nicely balanced flavour that will certainly appeal to UK tastes, and early indications are that it is well-suited to the UK climate. I really like it.

We have found it slightly prone to mildew but resistant to scab, and it always produces nice clean apples. It was one of the few apples in our collection (along with Rajka, another disease-resistant one) that produced well in the dreadful 2012 season, so I think the disease-resistance that was part of its development really works. Also, being new to the UK, and with a somewhat obscure parentage, it is unlikely that the UK bugs and diseases will be able to adapt to it soon.

This sounds to me like a good new candidate variety for planting for unsprayed/untreated production, not withstanding FB's comments on the inevitability of eventual disease-resistance breakdown.

I see from its wikipedia entry that it is subject to a patent (U.S. Plant Patent 7197 and Report 225-1992 (AD-MR-5877-B) from the Horticultural Research Center ). Does this mean that it can only be grown under license in the UK? And is one allowed to use it 'freely' as a parent in crossing? Given it's left-of-field parentage and the good qualities you describe (particularly scab resistance), I fancy crossing it with one or two of our traditional varieties, just so that I can say 'I'm using the latest commercial varieties from the US!!!'.

[Marcher]

I see from its wikipedia entry that it is subject to a patent (U.S. Plant Patent 7197 and Report 225-1992 (AD-MR-5877-B) from the Horticultural Research Center ). Does this mean that it can only be grown under license in the UK

Yeah, probably, and thus it will probably only be open only to commercial growers. Jazz is a good variety which is also patented, a shame because I'd grow it if it wasn't. If you see it growing anywhere then it depends how closely you follow the law as to whether or not you decide to sneak a cutting. T
here aren't really commercial orchards in my part of the world sadly.

[FB.]

And is one allowed to use it 'freely' as a parent in crossing?

You can't help it if the bees take pollen from Honecrisp and fertilise your trees with it.
Equally, if you had a Honecrisp and a fruit dropped on the ground, the seed sowed itself and grew into a tree, how would you know that Honeycrisp was the parent of the seedling.

So you should be able to use it for breeding, but you will be in trouble if you propagate Honeycrisp trees without permission.

I still think that it won't turn out to be a "wonder-variety" - I've seen enough of these released over the years to know that the breeding stations have to sell new varieties to keep them in business.
I think that further field trials will reveal problems for home-growers - in addition to the known problem of mildew.

[FB.]

I just noticed some of the less-than-flattering comments on Honeycrisp (in my experience, it's more important to listen to the minus points than to get all loved-up on the plus points; the plus points will take care of themselves but the minus points will come back and haunt you):

"..... problems with rot forming at stem punctures, bitter pit, bruising, soft scald, uneven coloring and ripening and short storage....... choose the right site <and> the problems with Honeycrisp go away.........variety must be starved to perfection........grown on low organic matter soils...... alternate-bearing tendencies........needs chemical thinning followed by hand thinning.....it takes as much attention as peaches....Growers report that pests like Honeycrisp as much as consumers do....codling moths.....It’s like they have a GPS for it....."

[FB.]

More Honeycrisp complaints - from an official source:
https://docs.google.com/viewer?a=v&q...LdEkfYZyYjtMyw

[sugar]

Do you have a list of these 20 resistant varieties? They might be of interest to people in the UK.
And picking up on FB's post, are they all based on possession of the single Vf gene?

The actual list is here : http://rwdf.cra.wallonie.be/download...oix_POMMES.pdf

It's in french, and you should go to the second page (the first page are traditional varieties, that are not part of the RGF-list)

All trees in the table on the second page are RGF apple varieties, there's one English variety in the list (Grenadier), FB indicates it performs good in the UK.
OÏdium is powdery mildew, Chancre is Canker and Tavelure is Scab.
++ means very good + good,...

Besides the ilnesses, there are 3 columns assessing the taste (Table = hand fruit; Culinair: cooking and Jus/Cidre : Juice or Cider)

The list indicates that some varieties of this list are susceptible to canker / scab in certain conditions

[FB.]

In the link provided by sugar, Boskoop is reported to have no special resistance to anything.
This is almost certainly due to it being widespread in Europe and having been grown there for a long time - like Bramley in England.
For me, in the UK, where Boskoop is rare, I find it to have strong resistance to almost everything.
I have a Gravenstein on trial with the same expectations; it's considered to be a bit prone to problems in Europe but not grown much in the UK so ought to be fairly trouble-free over here, like Boskoop.

Noticeable is that the "non-traditional" "Variétés non traditionnelles"
varieties in the list, have higher disease resistance. This being yet more evidence of localised strains of pests and diseases which have adapted to attack the popular "local" varieties which have been widely grown for decades, but the diseases struggle to attack less common varieties.