The dwarf white pine has mealy bug which hide in the bark scales as well as living on the needles. It is only five feet tall so I can reach all the branches.

Will soap and water harm the waxy cuticle on the needles?

Will a dormant oil spray harm the needles? If not should this be done in late winter, early spring?

Any other ideas given that systemic insecticides are not available to homeowners in Ontario?

Update: The plant kept going downhill even after soap and water. When there was substantial foliage die back after a winter I pulled it out and found very few roots.

1 Answer 1


Since the tree is small, if you have the time, you can kill the bugs by taking a cotton swab or cotton ball dipped in pure rubbing alcohol and giving each of the critters a good swabbing drench with it. This should kill them pretty much immediately, although it may not make them drop from the plant. A nice blast of water to all the sides of the branches and leaves this spring should help dislodge their carcasses once they have died. (Cleaning the dead bugs off the tree will help you find any you missed and help you keep watch for new infestations.)

  • Can I spray to needles with rubbing alcohol as well?
    – kevinskio
    Feb 14, 2014 at 17:25
  • I've heard of people spraying houseplants with diluted alcohol (9 parts water to 1 part alcohol) but I don't know if that's strong enough to kill full grown bugs or if it's just for prevention or mop up. I'd still go ahead and dab all the bugs you can with the full strength stuff, and then try a dilute spray for the rest. I'd also try the spray on a small part of the tree and wait a few days before I did the whole thing, just in case it has a bad reaction to it. Better to be extra cautious than sorry!
    – TeresaMcgH
    Feb 14, 2014 at 18:21

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