Phil L wrote:
I've had these almost every year in the greenhouse and now they are back
again, they first show up on the surface of the soil and look like tiny
white specks on the compost under the leaves (just some fuchsia cuttings up
to now, but I expect them to spread), and on the underside of the leaves,
I've squashed as many as possible by running my finger over obvious sites of
infestation, but is ther something I can spray onto the plants? - I don't
want to use any other insects for several reasons, the main one being I'm
too stingy!...are there any home made ways of eradicating them? ... or
chemical sprays?

For many years I have sown a small tray of French Marigolds in my
greenhouse in order to discourage whitefly, and it has never failed. As
soon as the first true leaves appear above the cotyledons it is
effective. When transplanted between the greenhouse plants they make a
pretty addition to the greenhouse; as little as two have been adequate
for my 6ft by 8ft greenhouse. And,of course,it is organic.( i understand
that tagetes are also good but I have never tried them myself). p.s.
they will also see off red spider mites.