December 10, 2011
Recently moved in, so not sure but looks like aphids (underside of leaves covered w/ small, white insects) took over this 20+ yr-old tree. Will pruning drastically now help prevent a repeated infestation next year or should I wait ’till spring to prune. Tree is +/- 15 ft and apparently never was pruned. Owner sprayed w/Malathion but little/no effect.
December 12, 2011
Whether it's aphids or some other bug, I would recommend using neem oil to rid the plant of these pests. Here is more information: https://www.gardeningknowhow.com/plant-problems/pests/pesticides/neem-oil-uses.htm
Tangerines rarely need pruning but since yours has never been pruned, it may not hurt to do so and later winter would be the best time to do it.