Canker is commonly spread by woolly aphis, and the first symptom is the appearance of small blisters on bark, which slowly grow larger. If canker is present, slicing these blisters through with a sharp knife or chiselled will show that the wood has been stained red. To remove And move canker you cut it out with a knife and clean up the wound thoroughly with a stiff brush. You should also examine the tree for loose bark, and remove it. You should also look for what appears to be a small tufts of cotton wool; these have been produced by the aphids, and should be brushed away and then scrubbed either with an insecticide or methylated spirit.
Occasionally canker is left untreated fault long periods, and produces large excrescenses on the
trunk and branches. These should be cut away where possible, but the careful not to remove a complete ring of
bark, because this will cause either the death of the branch or the tree. Any aphids present should be sprayed and then brushed away.
GLASSINESS or water-core
I first noticed this in the variety Claygate Pearmain on 1 October 2004. The apples should have been at their
best. On slicing through, they were transparent around the core and a little further into the flesh. The appearance
is most odd if one has not seen it before. In severe cases the skin may appear crinkled on the surface. One or
two of the fruit also showed slight symptoms of bitter pit, which seems to be a related condition.
I do not know the cause of this, but in that year, the tree was not well watered; since then I have
attended to it and the condition has not recurred.
Apple mildew, affected shoots and leaves are white and mealy ; they are covered with a white powdery
substance and if you rub this between your fingers the smell of mould is obvious. Affected leaves
cannot be cured but should be pinched out or rubbed and sprayed with insecticide
(aphids are frequently present too). The mildewed shoots sometimes send out good leaves later,
so if it's a leading shoot, you may be justified in not pinching out the tip. This is not usually
a major problem on a healthy tree, though I have noticed that some varieties are more susceptible;
Allington Pippin and the Dumelow's Seedling both seem to get more than their fair share.
Nigel Deacon, Diversity website
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