Pacific Northwest Plant Disease Management Handbook

Azalea (Rhododendron spp.)-Phytophthora Root Rot and Wilt

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Latest revision: 
March 2024
Image related to Azalea (Rhododendron spp.)-Phytophthora Root Rot and Wilt

Rotted roots and branch dieback from Phytophthora.

OSU Plant Clinic collection, 2012.

See:

Rhododendron - Phytophthora Root Rot

Note: Azalea cultivars Formosa, Fakir, Corrine Murrah, Merlin, and Hampton Beauty had the lowest root rot ratings but were not different statistically from 28 other cultivars. R. poukanense is a resistant species.

Pscheidt, J.W., and Ocamb, C.M. (Senior Eds.). 2024 Pacific Northwest Plant Disease Management Handbook.
© Oregon State University.

Use pesticides safely!

  • Wear protective clothing and safety devices as recommended on the label. Bathe or shower after each use.
  • Read the pesticide label—even if you’ve used the pesticide before. Follow closely the instructions on the label (and any other directions you have).
  • Be cautious when you apply pesticides. Know your legal responsibility as a pesticide applicator. You may be liable for injury or damage resulting from pesticide use.

Trade-name products and services are mentioned as illustrations only. This does not mean that the participating Extension Services endorse these products and services or that they intend to discriminate against products and services not mentioned.

H - Home garden packaging commonly available.     O - Acceptable in organic production.