Mike Echo writes:
My lemon tree's branches are all quite black and most branches are
covered in what look like insect eggs on them (colour and size of sesame
seeds). The underside of the leaves are mostly okay but have some of the
same eggs.

Ah, you've got yourself a crop of aphids. They can be moved with the
gentle touch of a finger? If not, then they are not aphids, though.

For aphids, spray with a 1:3 dilution of methylated spirits. The aphids
die instantly.
--
John Savage (newsgroup email invalid; keep news replies in newsgroup)