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2 problems with apples


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  • 2 problems with apples

    If I can get the photographs to load.... comments (and solutions!) invited on two apple tree problems:

    Photo 1: I noticed some twigs have died back and produced white crystals! I don't spray the trees (clearly I should!) and am at a total loss what it might be. Although only evident on a few twigs I've removed the branch as a precaution and on closer inspection can see these crystals forming at every joint... What is it, please, and what action is advised?

    Photo 2 (different tree) the underneath (i.e. the blossom end) of the apple has a series of small brown markings (the top/stem end is usually fine). For the photo I've selected the worst example I can find with several of these blisters but most of the fruit has one, two or three such markings rather than the dozen on this particular specimen. A friend suggested "lack of calcium" but I have no idea if that is true or, even if it is, how to solve it.

    Suggestions welcome!
    Attached Files

  • #2
    The white "crystals" look like whooly aphid. They wrap themselves up in an excreted blanket of white fluff that serves to protect them against predators.

    The scabby brown marks on the apples are ... well scab a common apple disease caused by a fungus.

    Whooly aphids can be individually squashed or sprayed.

    Scab can be prevented by spraying with fungicide or by gowing resistant vaieties. Do a search on this forum and you will find a treasure trove of useful info on both problems from our inhouse apple expert FB.


    • #3
      As already said:
      The white furry things are woolly aphids.
      The brown blotches are scab.

      Woolly aphids damage the bark of young stems, which become distorted and may get infected with canker - which is a common cause of dieback in branches.
      Woolly aphids prefer shadier places.
      The easiest way to deal with woolly aphid is squash them as soon as you see them. Natural predators will also attack them.
      Insecticide often won't work because the woolly coat protects the aphids.

      Scab is a fungal disease, caused by the surface of the fruit remaining damp for several hours or more. Some varieties (especially the popular varieties) are quite prone to scab while others (often less-well-known varieties) are resistant. Fruits are most vulnerable to scab infection early in the season, when the fruits are small and tender.
      In bad years any tree may have scabby fruits. If your tree produces good fruit in most years, then just consider this year to be a bad one. The only fairly sure ways to deal with scab is a spray routine or to grow resistant varieties.
      As long as the fruits don't split and rot before they're ripe, a few scab spots shouldn't be a problem.

      Whatever you do, don't go pouring on the fertilisers because they will make the problems even worse - they'll cause more young shoots to grow, which the woolly aphid will attack and also the scab fungus will have more young leaves (or fruits) to attack.

      The suggestion of calcium deficiency would be associated with bitter pit - dark-coloured areas under the skin, rather than dark scabs on the skin that you have.
      In my experience - and contrary to what many people say - I believe that bitter pit is more caused by too much nitrogen, rather than not enough calcium, although certain varieties are naturally much more prone to bitter pit than others.


      • #4
        Thank you both, brilliant responses, will do the necessary (and search out earlier discussions now I know the terms), many thanks. bb.


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