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Port Orford cedar root rot

Phytophthora lateralis

17 host plants

Last updated

Data Coverage 3 of 6 dimensions
Causal Agent
Host Plants
Symptoms
Management
GDD Threshold
Regional Notes

Port Orford cedar root rot caused by Phytophthora causes decline and death of this valuable native species. Avoid moving soil or plant material from infected areas. Improve drainage where possible. Do not replant susceptible species in infested soils. Select resistant alternative species for affected sites. Proper drainage and good site selection are critical to prevent root disease problems. Monitor plants for early signs of decline or wilting.

Root rots thrive in waterlogged soil, so drainage is your most important intervention. Avoid overwatering and ensure the planting site drains well. Remove severely affected plants to prevent spread to neighbors through root contact or contaminated soil. When replanting, choose resistant species or improve soil structure before putting anything back in the ground.

Quick Reference

Causal Agent
Phytophthora lateralis
Host Plants
17

Management

Cultural Controls

  • Integrate several cultural and/or chemical tactics to manage this disease. Plant only disease-free plants. Inspect and discard any incoming diseased nursery stock. Amend soils with composted sawdust or bark mulch to provide good aeration for roots. Plant in beds raised so that the top of the bed is at least 12 inches above the surrounding soil. Ame
  • Plant healthy seedlings in soil known to be free of the organism. Do not plant in soil with poor drainage or in areas that receive drainage from roads. Prevent wounding at the base of trees or to roots from nearby construction or harvesting operations. Avoid extensive gardening (mulching and planting susceptible flowering plants) under cedar hedges
  • Preventive measures are paramount. Plant no deeper than the tree grew in the nursery. Dogwoods have shallow root systems, and planting too deeply can mean the tree will fail to thrive. Dogwoods are understory trees, so plant where they will have at least partial shade. Provide supplemental water during the summer; water with a soaker hose 6 inches
  • Do not overwater plants. Blue cultivars should be grown at a pH of 4.5 to 5.0 and pink cultivars at 5.5 to 6.0. Aluminum sulfate is needed for the blue color development but additions to the soil may tie up needed phosphorus. Provide good drainage for plants in beds, fields, or containers. Place containers on gravel beds (4 inches or more deep) to
  • Do not overwater plants. Provide good drainage for plants in beds, fields, or containers. Place containers on gravel beds (4 inches or more deep) to allow drainage. Do not place containers on poly sheets; they can prevent containers from draining into soil and allow contaminated drainage water to spread from the base of one container to another. Av

Host Plants (17)