"Rod" wrote in a message:

No Tar oil is not the one. In fact tar oil has often increased populations
of rsm by killing off overwintering rsm
predators. The oil in question is specifically formulated 'spraying oil'
I believe there are also vegetable (rape?)
oils made for the job. I've never used them - never needed to but know
folks who have with some success, at least with
the mineral oil based products but I don't think they are available for
domestic use.
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Whilst working for a famous market gardener, one of my less than pleasurable
jobs was to paint mealy bug infested grape vines using rabbit's tail
'brushes' dipped in a pure nicotine liquid. We also used pine tar oil as an
insecticide for eradicating red spider mites and others which was sprayed on
the bare branches in the greenhouses during the winter months. As I said and
as you rightly say, tar oil also kills the predators. In these more
enlightened times, I can't imagine that any gardener would be able to use
either.

Roscoe