Rhododendron davidsonianum · Shrub
Powdery mildew: Improve air circulation and avoid overhead watering; tolerate mild infections or apply fungicide if severe.
Vine weevil: Use nematode treatments in autumn for larvae or apply systemic insecticides to prevent adult feeding.
Silver leaf: Prune out and burn infected branches well below the visible symptoms to prevent spread.
Bud blast: Remove and destroy infected buds promptly; ensure good drainage and avoid late pruning that encourages new growth.
Rhododendron leafhopper: Monitor for nymphs in spring; use horticultural oil or insecticidal soap if infestations are heavy.