Pacific Northwest Plant Disease Management Handbook

Holly (Ilex spp.)-Phytophthora Root Rot

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Latest revision: 
March 2024

This Ilex × meserveae 'Blue Princess' has crown and root rot due to Phytophthora sp. Note the cut made at the base of the plant revealing necrotic discolored tissue.

OSU Plant Clinic Image, 2016.

See:

Rhododendron - Phytophthora Root Rot

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.