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  1. #1
    FB.'s Avatar
    FB.
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    Default Apple Disease Pictures (Canker/Mildew/Scab/WAA)

    For anyone who is interested, here are some pictures taken in recent weeks, from my own apples. The disease should be near the centre of each picture, to make it easy to see.

    More and better pictures are avilable further down the topic.......




    Canker (note sunken, red-ish bark):




    .


    Powdery Mildew (some apple seedlings - note the white powdery coating, curling/deformation of leaves and gradual death of the leaf - the brown edges)






    .

    Scab (small-medium brown-black spots on leaves/fruit that merge in wet weather):




    .


    WAA <woolly apple aphid> (clumps of cotton-wool-like material on branches/stems/pruning cuts resemble moulds but actually contain aphids):

    Last edited by FB.; 29-08-2009 at 09:36 PM.

  2. #2
    BFG
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    Thanks. Very useful.

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    pdblake is offline Cropper
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    Intersting, thanks. I notice you have some seedlings there. Just how do you go about growing them?

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    Quote Originally Posted by pdblake View Post
    Intersting, thanks. I notice you have some seedlings there. Just how do you go about growing them?
    The pips need to be separated from the core of the apple and then chilled below 7'C (a 4'C household fridge will do) for about a month. Separating form the core before chilling tends to improve germination.
    Then plant into pots and wait for the seeds to sprout.

    The seedlings will be very variable in their features - size, shape, disease resistance etc. They will usually take years to reach cropping age and may grow considerably larger than grafted apple trees.

    Many supermarket apples can grow their pips with no chilling needed, since they will have been stored for months in a cold store. But extra chilling would still be helpful for better germination.

    Seedlings will have an unknown father, which could easily be a crab apple pollinator - as used in many commercial orchards. Such parentage could seriously spoil your chances of a good sized and nice tasting apple from a pip.

    I grow my pips for grafting experiments and rootstocks - not in the hope of finding a great new variety. I am working on a couple of projects (I'll spare you the boring details), due to the very difficult fruit-growing conditions in my area (difficult if you don't spray and don't irrigate).

    At some point in the future, I plan to start making careful crosses of my old-fashioned, tasty and disease-resistant apples.
    I will know both parents and I will have an idea of what features many of the offspring will have; "offspring tend to resemble their parents" - said one great genetics scientist.

  5. #5
    StephenH is offline Tuber
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    So now I know what my tree's got: wooly aphid. Thanks.
    Next question - how do zap them organically?

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    pdblake is offline Cropper
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    I think I might have a go at that. I don't mind if I get a crab apple to be honest, they can always go in the chutney

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    Quote Originally Posted by StephenH View Post
    So now I know what my tree's got: wooly aphid. Thanks.
    Next question - how do zap them organically?
    WAA are troublesome for two reasons:
    1: they make wounds which cause knobbly branches and allow canker to enter.
    2: the woolly coating is non-living and therefore gives them good protection from sprays.

    The rootstocks prefixed with "MM" are fairly resistant to WAA, but they are fairly vigorous.
    MM106 is very easy to find. MM111 is harder to find. The other MM's are very rare.

    WAA also attack the roots and can cause stunting of the tree (apparently WAA can travel as deep as 4ft below ground) and there is no ability to get those deep aphids, since chemicals won't penetrate far enough down and will be absorbed into the soil.
    Aphids on branches are best squashed (it gets messy because they have red "blood") or scrubbed off with a toothbrush. Normally, when WAA populations get noticeably large, small (3mm long) gnat-like wasps will come along and use their sting to inject an egg into the aphids and a tiny wasp develops inside and eventually the aphid bursts and the wasp emerges - like in the film "Alien".
    Other predators such as earwigs, hoverfly larva, ladybird larva and lacewing larva may also take their share of the WAA, but it seems as if once one predator type has arrived, other predators steer clear - perhaps to avoid competition, since there are always plenty of aphids to go around.

  8. #8
    FB.'s Avatar
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    Quote Originally Posted by pdblake View Post
    I think I might have a go at that. I don't mind if I get a crab apple to be honest, they can always go in the chutney
    Best that I can suggest is to shop-buy your favourite apple, since half of the genes in each pip will be from your favourite apple. You'll just have to take a chance on the genes provided by the "father" - and hope that the pip got lucky.
    Alternatively, find a couple of apple trees near to you and collect some pips (they will probably have pollinated each other, so by tasting the fruit from the trees, you can get an idea what the offspring fruit might be like))
    Last edited by FB.; 29-05-2009 at 10:13 AM.

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