In article ,
Len Buffey wrote:
Can anyone tell me how to prevent my Snowball Tree, viburnam opius 'Roseum'
from being attacked by black ants ? They seem to be associated with some
sort of black deposit on the underside of the leaves which curl quite
tightly. I would like to avoid a chemical solution if possible

It is not being attacked by the ants.

You have some sapsucking insects (or perhaps mites) on the leaves,
which are excreting honeydew. The black is a fungus that grows on
honeydew, and the ants are collecting it. Neither does the slightest
harm - it is solely the sapsuckers that do that.

Spray it THOROUGHLY (including inside the leaves) with a soft soap
solution (e.g. Savona), a rape seed oil solution (Naturen), washing
up liquid solution with a bit of methylated spirits or a pyrethrum
or derris based insecticide. All are relatively harmless and
biodegrable, but I favour the earlier ones.


Regards,
Nick Maclaren.