Phytophthora ilicis

Plant Damange:

Foliar leaf spots, shoot blight, and stem cankers.

Single Host:

  • Holly (Ilex)


This disease is found in holly orchards and in both field- and container-grown nursery crops. While disease development is favored by cool and misty conditions, it can be found wherever holly is grown in western Oregon.


Spores infect pruning wounds, spine punctures, and leaf scars. During warm conditions, this disease subsides; after a prolonged hot summer, the pathogen’s survival is greatly reduced.


This pathogen survives as spores in diseased stems and leaves. Spores become active again as the fall rains begin.