White flies can be kept at bay with periodic sprays of insectidal soap or horticultural oil. Complete coverage of the undersides of the foliage is critical for effective control. You will also need to spray again twice more at 2 week intervals to help break the life cycle of the pest. There is not much to do about them now that we are in the mid to late fall season and the pest numbers are declining anyway. But they'll be back next spring and summer so when they begin to appear try one of the above mentioned sprays.
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