How susceptible are canyon live oaks to Phytophthora ramorum?

Canyon live oak is an intermediate oak, meaning it is between the red and white oak groups. P. ramorum/SOD primarily infects only red oaks; however, it does also affect the intermediary canyon live oak.  In northern California (Humboldt County), canyon live oak infected with P. ramorum leads to dieback of large branches. In the Bay […]

How do I know if my area has been evaluated for sudden oak death?

If you live in a California county that is known to have sudden oak death (SOD), you can check to see if your area has been evaluated for the presence of the pathogen that causes SOD (Phytophthora ramorum) by downloading the free SODMAP Mobile app.  Doing so will allow you to see if trees have […]

My redwood has severe dieback and is near a coast live oak with SOD. Could the redwood have SOD?

Most likely the redwood is experiencing symptoms related to cycles between drought and rainy periods. However, if there is a significant presence of California bay laurels intermixed with redwoods, there may be enough pressure from the SOD pathogen to also cause problems on redwoods, both native and exotic. Any SOD oak infections are likely directly connected to […]

If reforesting an area impacted by SOD with local acorns, what can be done to prevent spreading the pathogen during planting?

Take the following precautions when using local acorns for oak reforestation projects in areas impacted by SOD to help minimize pathogen spread. Place acorns in a 10% dilution of bleach for 10 minutes then rinse twice with tap water. Make sure volunteers’ shoes are free of soil, mud, and organic material. Be sure tools being […]

How can I be sure I’m not spreading SOD with my tools?

The most important part of ensuring that tools will not spread SOD is to be sure that no organic debris or soil is present on the tools. This applies to all portions of each tool, including parts that may not be visible (like the return of a chain in a chainsaw or the interior of […]

I have a very small bay tree that has leaves with P. ramorum symptoms. Should I just remove the tree or take a sample first?

It is always advisable to first have a tree tested before removal to be sure P. ramorum is present.  If you are noticing symptoms in spring, attend a nearby SOD Blitz for information on sampling and lab submissions.  For more information, go to sodblitz.org.

Does rain affect preventative phosphite (e.g. Agri-Fos®) treatments for oaks?

When treating oak trees with phosphites to help prevent SOD, it may be beneficial to apply the topical treatment to bark that is dry.  Rain occurring after the treatment (even immediately after) does not affect the application. If injecting phosphites, it may be better to avoid rainy days, as lower evapotranspiration is often documented for […]

I have an oak in the Bay Area that is oozing liquid from the trunk base. Should I test it for SOD? If so, how?

When trying to determine if an oak may have SOD (caused by the plant pathogen Phytophthora ramorum), the first step is to determine if the tree lies within 1 km of a known outbreak.  This can be done by accessing SODMAP at www.sodmap.org or by uploading the free “SODMAP Mobile” app to your smartphone.  Stand next to […]

How long can Phytophthora ramorum survive in wood chip mulch?

Survival of P. ramorum (SOD pathogen) in wood chips depends on a few factors: Were the chips allowed to become wet? What size are the chips? Is green waste present? What time of year was the wood chipped? Where in California are the chips located? Chips that are piled wet or tarped and include infected […]

How long can Phytophthora ramorum survive in soil moved from an infested area?

Survival of P. ramorum (SOD pathogen) in dead hosts or non-plant substrates is extremely variable and strongly affected by climatic factors. Although a comprehensive study on this topic has not conducted, extrapolating from several studies we can say the following: Soil becomes more infectious from late winter to early summer in the presence of rainfall, […]

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