On 04/08/2012 12:53, andrew1 wrote:
Hallo, this is my first post and although used to forums of another kind
was pleasantly surprised to find this one, so Hi and well done for
setting this forum up.

My concerns are with a 20 yrs old crab apple tree we have. Not sure if
it's an edible version or not, but we have had an infestation of the
woolly aphid this year which is worse than before. In fact it has taken
over a rather large branch and sub-branches (scuse the lack of gardeners
techi language here!) and all the leaves have fallen off.

That sounds like more than just an attack of woolly aphid. But the quick
cure assuming the tree isn't too huge is a stiff brush dipped in meths
and applied to the wounds with the infestation and white fluff.

Brush tied onto a long stick will get you a fair way up with a bit of
practice. Tedious but do a bit at a time and keep at it all summer.

Conventional contact insecticides don't work since the wool is a very
good barrier layer. Systemics will but then you can't eat the apples
this year. And it may take a couple of goes to zap em entirely.

Once they have a tree colonised they are very hard to eliminate.

The main part of the tree they have not got to yet, but this rather
forlorn lower branch is practically bare now whilst the remainder is
still quite green.

They are getting into the main trunk and I can see further up the tree
they aare beginning to find homes, but my concern is with the health of
this dying looking branch and whether it will revive if treated or
whether I have to remove it completely.

I'd leave it on and treat the woolly aphid. At the moment with meths on
a stiff bristle brush (wear eye protection meths really hurts in the
eyes). Then in winter a classic tar oil wash when the tree is dormant
with the modern feeble Jeyes fluid (protect plants underneath).

Problem is this tree is now becoming quite tall and to either go
scrubbing the aphin infestation as I have seen mentioned elsewhere on
the net or even spraying that high is going to be extremely awkward to
say the least.

Can anyone tell me in somewhat layman's terms quite how I might deal
with this please and will I need to cut this rather large (relative to
the tree) branch off?

Try and treat it first. Lopping things off will leave a large wound that
the woolly aphid will definitely exploit (and may let disease in).

A picture would be helpful since the branch might have something
seriously wrong with it as well as woolly aphid. I have never known them
cause all the leaves to drop even with serious infestations.

--
Regards,
Martin Brown