Growing fruit trees - Organic vs Un-treated

[FB.]

I am not convinced that codling moth attacks are strongly related to variety, although that might be a factor.
The prevalence of codling moth is mainly affected by climate and orchard hygiene. If you live in the south of England, and have a period of good summer weather, and don't keep the floor of the orchard clean then you are likely to get codling moth in your apples, regardless of the variety. Once codling moth is in an area it tends to stay there.

If you grow multiple varieties, the codling moth are very fussy and will head for Discovery or its relatives. If you have mono-culture, with a thousand trees of the same variety, the codling moth have to eat what's available or they die. I don't much like lamb, or mushrooms, or cauliflower, but I'll eat them if I'm hungry.

For me, with one or two of each of a couple of dozen cultivars, every season sees the Discovery group of apples by far the worst affected while the others next to them remain almost free, if not completely free from damage.
I am always happy to eat a Spartan or Fiesta straight from the tree without fear of finding half a maggot, but experience has taught me always to cut open the Discovery-type apples because infestation rates are so high.

In my area, the Codling show a definite preference for certain varieties and disinterest in other varieties.

[sugar]

The discussion on the codling moth is interesting from another point of view as well.

This moth can be controlled with a biological insecticide based on the Granulose virus (Granupom). You will be applying a virus that is specifically aimed at killing the codling moth. The product has a safety delay of one day.

For me, this type of treatment is somewhere in between un-treated and the use of biological insecticides (in the latter case you are spraying poison harvested from plants, there is no difference for me with spraying chemical compounds from a plant) or sparying Copper based chemicals.

[FB.]

My general approach to fruit growing has been to try numerous varieties as cordons or minarettes and those which are among the least affected by pests and diseases get propagated onto full size rootstocks to grow as large bushes or trees.

My entire focus is on varieties which are trouble-free without any care or attention. Just the way nature always intended; natural selection causing the weeding-out and extinction of those which aren't healthy and productive.
Codling moth prone varieties would have all their fruit destroyed (pips eaten by codling larva) and no pips to produce offspring. Triploids, although tending to be healthy and vigorous, unfortunately won't produce many viable pips due to genetic abnormalities.
Same with other pests, such as woolly aphids. Natural selection in ancient times would have weeded-out those most prone.
There are a number of woolly aphid resistant (or partially resistant) old varieties too. Discovery and Scrumptious - being from a time when chemicals can be used to control insect pests - are also prone to woolly aphid.

[boundtothesoil]

I am not convinced that codling moth attacks are strongly related to variety, although that might be a factor..... The prevalence of codling moth is mainly affected by climate and orchard hygiene.

I definitely agree regarding climate and orchard hygiene being major factors, but am still with FB regarding very significant varietal differences in prevalence of attack, provided the moths are given the choice.

I looked up the Midox 'Early warning manual for diseases and pests of apples' aimed at commercial growers in the 1970s, and within the diagnostic flow-diagram the first mention of Codling moth comes in the 'mid-June to harvest section', with 'is there a reddish ringed entry hole in fruit?' and 'are eggs with the appearance of fish scales found singly on the foliage or fruit from the middle of June onwards?' -in both cases 'suspect codling moth'.

As you say, few if any varieties will have well developed red colouration in mid- June when the female moths are laying their first batch of eggs. However, I guess that the very early varieties like Beauty of Bath could be slightly more advanced in their development by this time, and not present the 'ideal' substrate for the first wave of egg laying from the moth's point of view! A similar argument might be advanced for very late varieties, although they could be 'ideal' with respect to the second wave/generation of egg-laying. The logic of this argument would suggest that mid-season varieties will generally be worst affected, but FB's Codling-prone Discovery doesn't support this.

I've just looked at the Midox guide again and under the recognition section for Codling moth it quotes May-June for 'Brownish moths laying eggs on leaves and fruit' - even earlier from the standpoint of the developing fruitlets and their specific varietal characteristics.

[orangepippin]

There is clearly a pattern of attack at FB's location, but I am not sure if the same pattern holds elsewhere. In my area I have not noticed Discovery being a particular target, but my lone Spartan and Kidd's Orange Red trees are often infected - both very late varieties. Until this thread I had not considered this issue as variety-specific, but my impression was that late season varieties were the more likely victims (and similarly my early season Opal plums are rarely attacked by plum moth whereas my late season Marjories Seedling is often hit). I'm certainly going to pay more attention to it this year. My hypothesis is that CM favours late ripening varieties - in my area at least. I'm further north than FB though, and it may be that the CM generations are different here.

[FB.]

It may be due to climate - amount of sunshine, average day/night temperatures, amount of rainfall - and how all these interact to produce fruit colours, flavours and aromas.
It may also be due to localised strains of codling moth which have evolved a special ability to attack certain varieties prevalent in their local area.

Somewhat connected to this is that Bramley and John Downie are the most common varieties around here, and the woolly aphids seem to be attracted to them in preference to most others.

With its connections to Essex, and its ability to tolerate the punishing summer mildew attacks, and its ability to cope well in dry alkaline soil, Discovery is bound to be particularly common around here - hence it being more likely to have strains of pests which attack it.
For now, Discovery's disease resistance remains quite good, but if it continues to be widely grown it will eventually become "slightly susceptible" to many diseases, just as Worcester Pearmain and other old varieties have.

Something also to consider in this area is the high temperatures and strong sunshine - not just the number of sunshine hours, but the tendency of the sun to be very strong due to the absence of cloud cover in most years due to being a naturally very dry location (driest in the UK).
My Discovery apples (and James Grieve, Beauty of Bath, Red Devil and one or two others) suffer from sunburn/sun-scorch. The heat is exaggerated by the very light, dry, sandy soil. My trees usually flower earlier than others because the dry, airy soil warms very quickly in spring. I had a James Grieve flowering in the middle of April on more than one occasion. The late-flowering varieties, such as Crawley Beauty often flowering in the first half of May.

This hot, dry climate may be causing the red pigment on Discovery as a side-effect, and this then acting as a magnet for codling.
In this area, most apples are very highly coloured - exaggerated due to deficient nitrogen in the soil

Other curiosities in this area include "russet" apples do not have more than a slight hint of it on the skin. Egremont Russet, for me, is a round, smooth, yellow apple with an orange sunny side and brown dots (lenticels). Ashmead's Kernel is a smooth yellow apple with orange stripes.

[orangepippin]

My Egremont Russet apples were textbook russets in autumn 2012, covered all over with a lovely dull golden sandpaper finish. However that is the exception, in all previous years they have been 50% smooth-skinned with plenty of orange/red flush.

[Marcher]

The apple tree was the only one last you to be attacked by a disease. The pear, plum, cherry and grapevine all do fine. I'll see what the apple is like this year, if it shows signs of anything I'll spray it and spray the others whilst I'm at it, if not then I'll take my chances.
I try to avoid spraying anything if I can.

[boundtothesoil]

It may also be due to localised strains of codling moth which have evolved a special ability to attack certain varieties prevalent in their local area..

I guess that this is likely to be true. I know that a lot of serious research has been done on Codling moth over the years and wonder if this has been looked at -do adult moths tend to revisit the particluar tree, or at least the particular variety, that they hatched from, in preference to others?

I haven't investigated the scientific literature regarding the myriad of possible approaches to controlling Codling moth suggested over the decades, apart from spraying. But I wonder if orchard planning along the lines you hint at in one of the earlier posts in this thread has been looked at i.e. planting susceptible varieties at the centre of a 'protective' block ' of resistant varieties. I remember reading somewhere that female moths tend to fly generally within 100m of where they emerge.

One other question: it is often recommended that corregated card or similar 'traps' for CM caterpillars seeking a site for pupation are tied around the trunks of CM infected trees as a control measure. I've never got round to doing this. Has anyone ever caught any this way?

[FB.]

it is often recommended that corregated card or similar 'traps' for CM caterpillars seeking a site for pupation are tied around the trunks of CM infected trees as a control measure. I've never got round to doing this. Has anyone ever caught any this way?

I don't take any precautions at all against codling - I don't need to. No insecticide sprays, no biological controls, no pheromone traps, no cardboard strips, no running chickens under the trees to eat fallen fruit an grubs.

[FB.]

do adult moths tend to revisit the particluar tree, or at least the particular variety, that they hatched from, in preference to others?

Well, the moths which visited my trees must have come from somewhere else first. So whether they came from the now-dead old Worcester Pearmain (parent of Discovery) a few streets away I don't know.

When it comes to apple diseases, monoculture has caused diseases to evolve to be fairly cultivar-specific; master of attacking one variety (as would be grown in a commercial orchard block) but the modern diseases are not particularly good at attacking varieties other than those from which they originated (e.g. diseases from a James Grieve won't usually be particularly effective at attacking Worcester Pearmain, although many years of evolution would eventually see them adapt).

Alternatively, it may just be that some apple varieties are more attractive than others. As I said: it's only really the red sunny side of Discovery apples where the codling larva enter; it's very rare for codling entry holds to be on a shaded part of the apple.
So something about the red colouration of Discovery/Worcester is attracting them to enter at that point. Yet the purplish colouration of Spartan is not attracting them and neither does green or yellow on apples which don't develop much red, or apples which go from unripe to ripe very quickly and colour-up from green to red in about a week.

[yummersetter]

But the name implies that it is a pest of cooking apples and in my case its the Bramleys that get invaded - I have Ellison's Orange Red which rarely has a codling moth. Though I've never kept notes in the past it would be interesting to monitor the codling moth this year. Do bats catch them? We have a bat roost on the edge of the orchard and see them flying through the trees a lot - it might explain why we have had so few codling moth attacks recently. We also run chickens under some of the trees.
I usually find earwigs are sheltering in the damage where two apples touch ( and there's a leaf for camouflage). Whether they cause the hole or take advantage of some other insect's work, I don't know. So much to learn isn't there?
Going back to the thread - the only time I spray anything is applying Bordeaux mixture on the peaches.

[FB.]

We have bats.
A few sometimes roost in my loft in summer (seen them, found small amounts of droppings and found occasional chewed-up insects dropped on the loft boards) and possibly live/roost in the tops of the cavity walls too.

Live and let live; we barely know they are there, and they probably need all the help they can get to survive. Besides: I believe the law is complex when it comes to bats.

[FB.]

Though I've never kept notes in the past it would be interesting to monitor the codling moth this year.

I've kept records, and the basics are:

The codling heavily attack Ellison's Orange and Scrumptious almost every year without fail. Within a month of blossoming most of the Ellison and Scrumptious have been "holed" at least once, often two or three times.
Other varieties remain completely unaffected until most of the Ellison and Scrumptious have been damaged.
Then the Discovery and Red Devil bear the brunt of the second wave of codling. Worcester will be next on the list.
After the Scrumptious, Ellison, Discovery, Red Devil and Worcester apples are mostly "holed", the attacks then become more random. By that time, I've harvested the Beauty of Bath, Irish Peach and Epicure - with almost no damage.

[yummersetter]

According to ' Fruit Trees and their Enemies' pub. 1908, the remedy for codling attack is to spray the tree with arsenate of lead as soon as the blossom has dropped, as after eight days the calyx closes in and prevents the poison from being lodged in the eye. I guess that's not organic.