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what is white dust on underside of plumbago leaves
9 Mar, 2010
Answers
Is this the greenhouse climber or the hardy shrub?
9 Mar, 2010
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white dust like deposits are usually mildew or fungus, but it does seem rather early and too cold for that to be the cause. If it is mildew, you should be able to rub it off, not completely, but be able to shift it a bit. If that's what it is, spray with fungicide, but I'm not sure it will be at this time of year. A photo would be useful.
9 Mar, 2010