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  • Growing apples without sprays

    When I began to grow apples, I wanted to grow them without sprays.
    Here is the kind of information that I would have found very useful when starting out.
    Bear in mind that the information is from my observations. While I believe it to be correct, it is possible that I may have been supplied with the wrong varieties, or I may have muddled my notes, or I might have made a typing error.

    Common diseases

    Aphids
    Green or pink colours, with occasional blacks. Pink ones are the most troublesome. Green ones are the most common. Cause curling on the leaves and distorted shoots, which impairs photosynthesis, makes the tree look messy and protects the aphids in the curled-up leaves. They prefer the young leaves. Aphids secrete honeydew, which attracts ants. The honeydew drips onto leaves and fruits, which can become cause black moulds. These moulds are only superficial and not causing serious harm, except a slight reduction in light getting through to the leaves.
    Heavy and prolonged rain washes aphids off the leaves, so dry spells are when they're most numerous.
    Varieties of apples that flower (and leaf-out) early seem to miss the worst of the aphid attacks because the aphid populations are quite low early in the season (but early-flowering apples can suffer frost damage, although some are resistant to frost).
    Aphids can be squirted with a water pistol, which will control their numbers. Alternatively, natural predators will come along, although ants will guard the aphid colonies and may drive off predators.
    Hoverfly larvae are small, flattened, ribbed, yellow-orange maggot-caterpillar like creatures. They start off barely visible and end up about half-inch long.
    Parasitic wasps, like tiny, black gnats - they do not attack humans. The adults inject an egg into the body of an aphid and the wasp develops inside, until the aphid bursts and the wasp flies away.
    Wasp-infected aphids turn brown-black colour a day or two before they pop - and often the infected aphid leaves the colony, to wander off by itself, which can allow you to transfer some infected aphids to another aphid-infested plant in the hope that the hatching wasps will help.
    Occasionally, ladybird larvae appear. They look more like tiny, black, six-legged scorpions.
    Very occasionally, lacewing larvae appear. They are like pale-coloured, elongated, ladybird larvae and the lacewing larvae can move very fast when they want to.
    Finally, spiders. The webs of the numerous baby spiders can catch large numbers of the winged aphids as the aphids try to colonise new plants.

    A special type of aphid attacks apples; woolly aphid.
    Furry white masses that resembles mould, clustered on young shoots, pruning cuts or other damaged bark. Some woolly aphids migrate to attack the roots.
    The "wool" protects them from predators and I find that the parasitic wasps seem to be the best predator of woolly aphids.
    The aphids cause bark swellings and root swellings. Those swellings often split (especially in cold or wet weather), exposing the tree to rot-type damage. Canker may enter the wounds, which can be a serious problem for varieties with low canker resistance.

    Canker
    Fungal spores enter damaged areas of bark. Most severe when it is wet and is greatly increased by the presence of woolly aphids. Canker causes the bark to split, flake off and turn red-ish. Often, the canker has a sunken, cracked, black-ish middle. On susceptible varieties, the canker may spread up-and-down the branch, “unzipping” and flaking off the bark as it travels, or it can encircle the branch, preventing sap flow - and the branch dies.
    Cutting out the cankered areas is the only cure for susceptible varieties, although some resistant varieties will manage to wall-off and limit the canker by themselves. Choosing varieties some canker resistance is desirable, especially if the rootstock/apple variety is known to be susceptible to woolly aphid.

    Powdery mildew
    Common in the lower-rainfall areas. Unlike most fungi, it thrives in dry conditions.
    Young leaves are most susceptible. Seen as a white, powdery coating on leaf surfaces and often causes leaves to be small, distorted and grey-green coloured. Cutting off infected leaves as soon as the mildew is seen can reduce the amount of mildew that season.
    Hibernates in buds and comes out of hibernation when infected buds open in the spring. White marks on the bark around a bud often indicate hibernating mildew. Cutting off whitened areas will remove the fungus. Affected leaves or flowers may be small, pale and often have the white powder coating, although it can take a few days for the powder (spores) to develop. Infected flowers are not fertile.
    Choosing varieties with some resistance is the only defence.

    Scab
    Particularly common with long periods of rain.
    Young leaves and fruit are most susceptible and get less susceptible as the season progresses.
    Causes dark brown patches on the leaves or fruits, although fruit scab often seems to be a bit darker in colour than leaf scab. Scab lesions may merge and engulf the whole leaf or fruit. Badly scabbed leaves and fruit will split. In the middle of the dark brown patches, it may be possible to see tiny black sporing structures.
    Controlling scab is not easy, although scabbed fruit can usually be eaten or stored. Some people recommend raking up and burning all the leaves in the autumn, but if you’re not using sprays, probably the best control is choosing a resistant variety.

    Common rootstocks

    Apples are grafted onto a rootstock, which allow the production of apple trees with known characteristics - such as to control the eventual size, and to control how soon an apple starts to channel it's energy into producing fruit.

    M27
    Patio containers or dwarf bushes.
    Extremely slow growing - 5ft.
    Moderately susceptible to Woolly aphid.
    Only requires minimal pruning.
    My need to have fruits removed in the early years, to prevent stunting.
    Needs very good soil and adequate moisture. May not survive without feeding and watering.
    Canker-prone apple varieties not ideal on M27, due to need for regular watering and woolly aphid damage being infected by canker.

    M9
    Mainly for cordons.
    Slow growing - 7ft.
    Very susceptible to Woolly aphid.
    Needs good, moist soil.
    Will easily be uprooted in windy weather, unless staked.
    Produces better quality fruit than other rootstocks.
    Canker-prone varieties should be avoided on M9 for the same reasons as M27.
    Tolerates wet soil.

    M26
    Bushes and cordons.
    Moderate growing - 9ft.
    Moderately susceptible to woolly aphid damage.
    Will grow in most soils that don’t dry out.

    MM106
    Half-standards or bushes.
    Moderately vigorous - 12ft.
    Will grow in poor soils, but will need regular watering for the first few years in the drier eastern side of England.
    Resistant to woolly aphid.
    Causes early flowering in my area - by about two pollination groups, as compared to M26.

    MM111
    Standards, half standards or bushes.
    Vigorous -14ft
    Will grow in poor soil, but may need regular watering for the first two years in the drier eastern side of England. Roots are very efficient at gathering water, so MM111 is good for dry areas or light soils.
    Resistant to woolly aphid.
    May cause early flowering - perhaps by one pollination group as compared to M26.

    M25
    Standards or half-standards.
    Very vigorous - 18ft.
    Will grow almost anywhere, but may need regular watering for the first year or two in the drier east of England.
    Tolerant of woolly aphid.

    On poor soil and the drier parts of the UK, final height can be halved. In warm and damp areas, on good soils, the final height can be doubled.

    The variety grafted onto the rootstock plays a part in the growth rate and final size. Strong growing varieties can be grafted onto weaker rootstocks and weak growing varieties onto stronger rootstocks, to compensate.


    Some apple varieties that I grow, or have grown, on an estimated scale of 1-5, with 1 being weaker, earlier flowering etc. Low canker/scab/mildew resistance (levels 1 or 2) might struggle in the long-term, without chemicals.
    Woolly aphid resistant rootstocks reduce canker - may enhance canker score by one level.

    Annie Elizabeth
    Vigour 4
    Canker 4
    Scab 4
    Mildew 4
    Pollination period 4

    Ashmead Kernel
    Vigour 3
    Canker 4
    Scab 4
    Mildew 4
    Flowering 4

    Bramley
    Vigour 5
    Canker 4
    Scab 4
    Mildew 4
    Flowering 3

    Court Pendu Plat
    Vigour 1
    Canker 3
    Scab 4
    Mildew 4
    Flowering 4

    Crawley Beauty
    Vigour 2
    Canker 4
    Scab 5
    Mildew 4
    Flowering 5

    D’Arcy Spice
    Vigour 1
    Canker 4
    Scab 4
    Mildew 4
    Flowering 3

    Discovery
    Vigour 2
    Canker 4
    Scab 4
    Mildew 4
    Flowering 2

    Egremont Russet
    Vigour 2
    Canker 5
    Scab 4
    Mildew 4
    Flowering 1

    Ellison Orange
    Vigour 3
    Canker 1
    Scab 4
    Mildew 4
    Flowering 2

    Fiesta(Red Pippin)
    Vigour 1
    Canker 3
    Scab 3
    Mildew 4
    Flowering 3

    Golden Delicious
    Vigour 3
    Canker 3
    Scab 3
    Mildew 4
    Flowering 4

    Grenadier
    Vigour 2
    Canker 5
    Scab 5
    Mildew 4
    Flowering 3

    Howgate Wonder
    Vigour 4
    Canker 3
    Scab 4
    Mildew 4
    Flowering 4

    James Grieve
    Vigour 2
    Canker 2
    Scab 3
    Mildew 5
    Flowering 2

    Liberty
    Vigour 3
    Canker 2
    Scab 4
    Mildew 4
    Flowering 4

    Meridian
    Vigour 2
    Canker 3
    Scab 3
    Mildew 4
    Flowering 2

    Pinova
    Vigour 1
    Canker 3
    Scab 4
    Mildew 4
    Flowering 3

    Reverend Wilks
    Vigour 2
    Canker 4
    Scab 4
    Mildew 4
    Flowering 1

    Saturn
    Vigour 3
    Canker 2
    Scab 4
    Mildew 4
    Flowering 4

    Spartan
    Vigour 3
    Canker 1
    Scab 3
    Mildew 4
    Flowering 4

    Tydeman Late Orange
    Vigour 4
    Canker 4
    Scab 4
    Mildew 4
    Flowering 3

    Winston
    Vigour 3
    Canker 5
    Scab 4
    Mildew 4
    Flowering 4

    Winter Gem
    Vigour 3
    Canker 4
    Scab 4
    Mildew 4
    Flowering 3

    Worcester Pearmain
    Vigour 3
    Canker 2
    Scab 3
    Mildew 5
    Flowering 3
    Last edited by FB.; 20-04-2009, 12:06 PM. Reason: Updated to reflect additional disease observations.
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  • #2
    To continue with the vigour....

    The size stated for rootstocks is for an average vigour variety - vigour level 3.

    Varieties with vigour level 5 can add 50% (or about two rootstock class bigger), while vigour level level 1 can deduct 50% (or about two rootstock class smaller).

    Vigour levels roughly correspond to:

    Vigour class 1: M9
    Vigour class 2: M26
    Vigour class 3: MM106
    Vigour class 4: MM111
    Vigour class 5: M25

    So, for example, Bramley (vigour = 5) on rootstock M9 (vigour = 1) would average out as vigour level 3, so would be similar to an average variety (vigour level 3) on MM106 rootstock (vigour level 3).
    ...and so on.
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    • #3
      An addition to rootstock properties.
      I have some evidence that suggests rootstock M26 might enhance the resistance to scab by one level, since where I have the same variety on different rootstocks, despite the apples grown on M26 being in a shadier, damper area, they tend to suffer less scab.
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      • #4
        I have some other varieties that I am trialling at the moment, but that I haven't mentioned because I haven't formed an opinion on them yet - some I haven't had very long and some I acquired by mistake. I may make an update next year.
        They have mainly been acquired because other people seem to find them to be very disease resistant and suitable for "organic" or "no spray" growing. Some are varieties that originate fairly close to where I live, so they ought to do well here.

        At the moment, I can only really comment on their approximate vigour (mostly being grown as M26 cordons):

        Brownlees Russet: V2
        Cockle Pippin: V2
        Golden Russet: V2
        Laxton Superb: V5
        Norfolk Beefing: V3
        Red Devil: V3
        Rosemary Russet: V2
        Last edited by FB.; 31-03-2009, 05:51 PM.
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        • #5
          Apple scab, canker and mildew are caused by fungi. Canker in particular is not difficult to protect against, but the chemicals used can kill or deter beneficial creatures. Loss of beneficial creatures can then cause other creatures to take their place and the whole environment starts to get unbalanced, which can cause further problems, or other diseases.
          I'm a scientist in infectious diseases and quite often, patients are given antibioitics to treat an infection (a bit like giving anti-fungal sprays to a tree to protect scab infection). Unfortunately, all of the "good bacteria" on the person are damaged by the antibiotics, causing disruption to their defences against other attacks. I believe that, on trees, there are many "good fungi" that help protect against the bad ones by competing with them, as well as competing with fireblight bacteria.

          I use no sprays at all. I choose apples with partial or complete resistance to the diseases.

          Woolly aphids use the thick layer of "wool" to protect them. It prevents any chemicals getting to the aphids and hides them from the sight of most predators (tiny parasitic wasps kill most of my WAA). WAA have a habit of hiding between the inner wood and the bark around pruning cuts, which also protects them.
          Underground WAA are almost impossible to kill because the soil prevents pesticide from getting to them. Applying pesticides to the soil will kill the natural predators - and the natural predators are far less common than their prey, so they take much longer to recover from use of chemicals.
          Use of chemicals can also affecct bees. If you spray pesticides before or during blossom time, the bees that come to pollinate the flowers will be killed.

          The trouble with WAA is that the shoot damage they cause allows canker to enter, or causes tumour-like growths that make the branches very knobbly and unsightly. The growths often split in bad weather, which allows canker into the wounds.

          Anyway, use of sprays is entirely up to you. I prefer to let nature take it's course, since treatment for one problem often has unexpected side effects and may cause other problems.
          Last edited by SarzWix; 15-05-2009, 11:13 PM.
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          • #6
            I've put together some of FB's excellent apple growing information, and put it on this board so that it's easy to find, instead of having to hunt for it.

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