On 09/10/16 12:10, BobHobden wrote:
"Jeff Layman" wrote

They do suffer from Scale Insect and I find I have to blast them off with a
high pressure spray every couple of years, leaf by leaf branch by branch.
Your problem, as you cannot see it, sounds more like red spider mite which
it could well be as you have the plant under cover all year. I put ours out,
normally about March after the worst of any frost, they are against a S.
facing house wall and under a porch roof and a wisteria that runs the length
of the house wall, so have some protection. Not taken them back into winter
quarters yet, I await a forecast of frost for that.
Being under cover might also mean a lack of pollinators.

The main problem is soft scale, but there is something else. It isn't
red spider mite, as that is visible to the naked eye, and pretty obvious
under a x10 loupe. As far as I could tell, although it was warm in the
greenhouse (25+ deg C), nothing was moving on the leaves.

Leaves covered with sooty mould:
https://s9.postimg.org/y7y9tpt1r/Citrus1.jpg

Soft scale on underside of leaf:
https://s10.postimg.org/d555wbetl/Citrus2.jpg

Other pests:
https://s14.postimg.org/5husvneox/Citrus3.jpg
In comparison with the second photo, I think the small white insects are
the mobile stage of soft scale. But what are the black dots amount them?
Are the larger rust-coloured spots immature, but immobile, soft scale?

I've just noticed some other seedlings (longans) in the conservatory
suffering the same way. They weren't bothered while the citrus was
there, but now it's gone, it seems the scale and whatever else is
looking for something else to feed on. I'm moving towards chucking out
*all* plants seriously affected by scale, as that seems to be the
general fallback position in the absence of effective treatment.

Where is dimethoate when you need it?...

--

Jeff