Why does your Rhododendron uvarifolium have white powder? Diagnose the cause and fix it with our step-by-step guide.
A fungal disease caused by Oomycetes or Ascomycetes that thrives in high humidity and stagnant air. It manifests as a white, flour-like coating on the surface of the blueberry-shaped leaves, eventually leading to leaf distortion.
Small, soft-bodied insects that secrete a white, waxy, cottony substance to protect themselves. These pests suck sap from the Rhododendron, often appearing as distinct white clumps in leaf axils or under foliage.
Hard water or high-pH irrigation can leave white, crusty residues on the leaf surface as the water evaporates. This is not biological and does not typically cause wilting, though it can interfere with photosynthesis.
While scale often appears as bumps, some species produce a white, powdery wax coating over their bodies. This can give the entire foliage of the Rhododendron a dusty or speckled appearance.
Your plant might also be experiencing one of these issues:
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