I got a wild hair and built a light frame at the end of the
season to bring all my containerized outdoor herbs in for winter
cooking. Of course, I brought the bugs with them. Some hard sprays
of water and a some dilute horticultural oil seems to have taken
care of the aphids and white flies but my Basil and Kaffir Lime
trees seem to be attracting scale that won't go away. It just
keeps reappearing after manual removal.

Should I look forward to having to scrape it off once a week
for the rest of the winter or will multiple applications of
horticultural oil eventually take care of it.

And speaking of horticultural oil, I used it after really getting
disgusted at the "syrup" the bugs were producing on my plants and
increasing population of scale. I read where one state OKed its use
for edible herbs but I have yet to actually attempt to eat anything
I've sprayed. One source says it evaporates but that seems
counter-intuitive...for an oil to evaporate. Should this stuff
actually be used on culinary herbs? If not, what can get rid of
the scale?

Most of the stuff is growing pretty well under flourescents next
to an east facing window so I'll have plenty of herbs if I can
get rid of the bugs.

thanks,
gary