On 09/04/2012 17:20, Hedgecop wrote:
Hi All,

I have a Bay Tree on which the leaves are turning brown and falling off.
The tree has been very healthy for the last 5 years and this has only
started happening over the last 4 months. I have tried regularly
spraying it with various bug killers but with little or no success. I
have attached some photos and would really appreciate if anyone has any
ideas as to what the problem may be and how to solve it.

Thanks


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I'm seeing signs of scale insect and some sort of fungal leaf spot.
The best way of dealing with the scale insect on such a mature tree is
to use a systemic insecticide. However, since you have already used
insecticide, I think it would be wise to wait at least a couple of
months before you consider treating it again.

As to the fungal problem, this is probably exacerbated by frost damage
which can cause cell collapse, leaving soft tissue open to disease.
Wait until all danger of frost is over in your area (you don't say where
you are), then cut out all dead and seriously damaged wood. Then
reassess the shape of the tree and further prune it to shape, if
necessary. I can't recommend a fungicide because I'm not familair with
a specific disease of Laurus nobilis (Sweet Bay), so I suggest you talk
to your local garden centre about a systemic fungicide for your tree.
Take a sample of the damaged and spotted leaves to assist them.

Sadly, you will not be able to use your bay leaves for culinary purposes
until the tree is totally free of these chemical treatments. Consult
the label(s) or manufacturer for this information.

In the meantime, keep your tree well watered, allowing it to drain well
between soakings. I would be wary of feeding it until after the frosts,
as feeding will create soft growth which may be frosted again or prone
to fungal attack.

--
Spider
from high ground in SE London
gardening on clay