How to Prevent Human Caused Introduction of SOD to the Mid Klamath

Phytophthora ramorum causing sudden oak death is an invasive pathogen that first arrived in California due to diseased nursery plants, likely ornamental rhododendrons.  Since the initial human caused infections, it has spread aerially through the central and north coastal counties of California and Curry County in Oregon. The disease spreads by its spores. The spores are produced on the leaves of infected trees and can move several miles by air on the winds of spring storms.  These spores also fall down on the under story and soil below the infected trees and can be moved by people in the intentional or unintentional transport of soil, wood chips, firewood or other gathered forest products.  

You can follow these recommendations to prevent the human caused introduction of SOD into the Mid Klamath.

1. Know where the infections are

2. Learn to recognize symptoms.

3. Sanitize

4. Be cautious about bringing home potted plants.  

5. Know where your soil/wood chips/garden amendments are coming from.

6. Keep firewood local.  


1. Know where the SOD infections are

Sudden oak death is present in the coastal counties of Central and Northern California, and Curry County in Oregon.   If you know you are in an infected area you can take precautions to avoid unintentionally taking plant matter home with you.  The map on the right is a general overview of infected areas and quarantined counties.

The closest infection to the Mid Klamath region is in Redwood Valley, on private property and in Redwood National Park. There is widespread infection in Southern Humboldt County in the Redway-Garberville area. See more detailed infection maps on the UCCE website.

There are heavy infection levels in the bay area as well as Southern Humboldt County.  Marin County, Big Sur and Santa Cruz areas have been infected with SOD since the 1990s and have high levels of the pathogen.  Please take appropriate sanitation precautions if you are visiting these areas.

The SODmap project and mobile app is a useful tool for determining the risk of SOD infection on a local scale.  This app will show you if positive or negative samples have been taken nearby and show if you are standing in a high or low risk area.

2. Know how to identify symptoms

The symptoms of SOD vary depending on infected species.  Pepperwood and tanoak are the main
vectors of the disease, so identification of symptoms on these trees is important for establishing whether or not you may be in an infected area.  See the Symptom ID page for details on how to identify potential SOD infected host plants.  SOD infection cannot be verified by field observation only, the only way to identify Phytophthora ramorum is in a lab. Samples can be sent to UCCE in Eureka, see their publication on how to identify and collect samples.

The best way to learn to identify the symptoms of SOD is through experience. The UC Berkeley Forest Pathology lab holds many SOD Blitzes through California every year, including those hosted by the Karuk Tribe in Orleans and Happy Camp.  

The SOD Blitzes are communities coming together in the fight against  Sudden Oak Death. SOD blitzes inform the community about Sudden Oak Death, get locals involved in detecting the disease, and result in detailed maps of disease distribution. 

For Gatherers: It is important to familiarize yourself with symptoms of the plant(s) you collect.  First check to see if it is a host, and check what it's symptoms are.  It is always important to collect healthy plants, moving around unhealthy plant material spreads plant diseases including SOD.

3. Sanitize

If you travel through a SOD infected area it is best to clean your boots and your vehicle before you return home. SOD can be carried in mud, especially on bits of plant material.

  • Clean your vehicle of accumulated leaf litter and mud.  It is important to clean off this debris before you return home. 
  • Clean boots and tools of any mud.  You can use Lysol or a diluted bleach solution to disinfect your your shoes and tools.
  • Make sure no leaves or twigs are clinging to your clothing, hair, pets or livestock before you leave an infected area.

4. Be cautious about potted plants.

Don't bring home that sad sick plant that was on sale at the nursery. Plants carry disease that can spread to other plants.  Be especially cautious with rhododendron and camellia- they have an extremely bad track record for causing new outbreaks of SOD.

5. Know where your soil/wood chips/garden amendments are coming from.

Plant material, including wood chips and forest products used to make soil can carry pathogens.  It is important to know the source of your garden amendments to stay disease free.  

Soil companies are not required to sterilize their products and it is difficult to trace the source of their ingredients. While it is not usual that commercial soils are carrying pathogens, it is a possible risk that can be avoided. 

6. Keep Firewood Local.

 Moving firewood around spreads many forest pests, including SOD.  It is best to burn firewood near where you gather it.  If you are buying wood, know where it is coming from.  Know where SOD infections are, do not bring firewood from an infected area to the Klamath River.  

If you need to transport firewood long distances it is best to remove the bark at the cutting site and to keep it dry.