Phytophthora citricola

Plant Damange:

Foliar leaf spots, shoot blight, root crown rot, and root rot.

Multiple Hosts:

  • Pine (Pinus)
  • Rhododendron (Rhododendron)
  • True firs (Abies)


Foliar disease is often found in both container and field nurseries that use overhead irrigation during the growing season. Root rot occurs in areas that are poorly drained or subject to flooding.


Prolonged periods of leaf and shoot wetness promote the foliar phase of disease, especially under splashing rain or irrigation water. The disease spreads from leaves or needles into the branch and eventually into the main trunk. In water-logged soil, the pathogen can infect roots and will move up into the root crown and lower trunk of the plant.


This pathogen survives as spores in soil or container media.