Answer: Thuja occidentalis 'Teddy' does take on a bronze tinge in winter during the cold weather, so part of what you are seeing could be normal seasonal color variation. The oldest inner foliage on arborvitaes will also naturally brown and drop off in the fall. So again, part of what you are seeing could be normal. As far as the black and the mold or fungus, based on your description I am unable to identify what might be causing that. I would suggest you consult with your local professional nursery staff and/or your local county extension to obtain a firm diagnosis of what is happening, and then based on knowing that, determine how to proceed. IF it is something that requires a chemical control, your county extension will have the most up to date information on what to use and how/when is best to apply it for maximum results. Good luck with your shrubs!
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