I was outside today and noticed my holly plants are partly black, even the stems. Looks like oil soaked into them. On the underside of the leaves looks like white egg casings (looks like bird droppings) a bit. Can you tell me what is wrong with my plants and what I need to do?
Fungus or Infestation of Holly Plants
Certified GKH Gardening Expert
Your problem could be attributed to scale bugs, which commonly affect these plants and can result in sooty mold, the black stuff on your stems. Neem oil can help with both issues. Here is an article or two that you may find helpful: https://www.gardeningknowhow.com/plant-problems/pests/scale-bug-how-to-control-plant-scale.htm