On 01/08/2013 15:46, Pam Moore wrote:
Someone recently mentioned a diseased horse chestnut.

Me. I have also asked the RHS for specific advice about the supposed
expensive garlic juice injections supposed to help (I kid you not) for
about £400/year/tree with no guarantees whatsoever. Only worth
contemplating on a prized specimen tree if you have money to burn.

They said if we tried it to let them know if it worked. Their approach
is basically to chop and burn as is English Hertitages. I understand
work is under way to find resistant cultivars, but a lot of mature trees
are in serious trouble. I saw a load on one of the M1 services a couple
of weeks back all of them had it very bad.

There is a large specimen in our town. 2 years ago the leaves
gradually turned a dark chocolate colour. I kept an eye on it last
summer but there was no sign of it recurring. The tree looked
perfectly healthy. Today I noticed it looking decidedly brown.
Is this a disease? Will it eventually kill the tree?

Pam in Bristol

There is more than one disease that it could be but if the bark on
branches looks broken into bits and the trunk or branches are weeping
dark brown tar then it almost certainly is the nasty fungal disease.

The bad one on our village green had a low branch turn brown and die
back in a matter of two weeks about a month ago. It seems to be really
very fast acting once there is a ring of bark succumbed to the fungus.
Now is about the time the trees come under maximum stress and I expect
these warm humid conditions are perfect for fungus to take hold.

Recommended treatment is basically cut off all affected parts and
prayer. Oh and sterilise your tools before any cuts into good wood and
clean them meticulously afterwards. I think I posted all the stuff I
could find last time but no-one not even the RHS has any better advice.

A large tree in a public place will require a tree surgeon and they may
well recommend chopping it down entirely as the least worst option. Ours
tried to sell us this magic cure of garlic juice injections first.

It used to be a big problem in Brussels as the chestnut trees along the
boulevards had all got it to some extent and dry chestnut branches snap
like carrots without any warning. A few unlucky people get killed by
falling branches during storms almost every year.

--
Regards,
Martin Brown