"Spider" wrote in message
...


Hi David,

I don't think there's a connection between the white residue you can
remove
and the brown lesions you can't. No doubt you didn't even notice the
lesions when they were fresh as they were probably still more or less
green.
You are seeing them now because they have healed over like a scab.

By all means keep an eye on the shrub, but it doesn't sound too serious to
me. If the weather in your area is as good as it is here in SE London (16
deg.C), it would be a good idea to feed and water now so your Mahonia can
start building up more leafy growth to replace the damaged leaves, which
may
not be photosynthesising as efficiently as they might. One thing that
does
concern me slightly is that the white residue could be fertiliser splash
from a previous feed. Is this possible? If so, it could burn the foliage
and is potentially more harmful to your plant than any grazing bug.

Spider

Hi, Spider
thanks for the reply. Weather conditions are not too bad here now, 11C
at present although it reached 16C at the weekend. I'll go with your advice
re feeding and watering. I haven't fed the plant up till now as it was
planted in a good soil with plenty compost and then mulched. One explanation
for the residue could be that it's coming off the screenblock wall behind
the plant, although no other plants are showing the same! Hopefully it won't
be a problem,

regards,

David