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 […]

Other than for copper-based sprays, what control methods are available for cypress canker?

There are several  products that have been tested for controlling cypress canker. The following paper maybe the most useful one to compare products. Della Rocca, G., Di Lonardo, V., Danti, R. 2011. Newly-assessed fungicides for the control of cypress canker caused by Seiridium cardinale. Phytopathologia Mediterranea. 50 (1), pp. 65-73. The most effective active ingredients […]

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.

I just cut down a small infected bay. Do the root shoots carry P. ramorum?

Bay shoots do not carry P. ramorum because the pathogen is not systemic in bay.  Each leaf is infected independently. Additionally, there is no root infection in most P. ramorum hosts,  particularly California bay laurel.  However, when bays re-sprout, they may be re-infected.  

My coast live oak trunk is oozing. I sprayed the bark in January. Can you estimate how long it will be before the tree fails and we have to remove it?

The symptoms on your oak may be caused by a range of issues. If oozing is accompanied by the presence of fine sawdust, then the tree is dying. Even if it is still green you may want to consider removing it if its failure may cause harm to people or property. The fine sawdust is […]

What are the revised SOD treatment recommendations that were released in June 2015?

The revised SOD treatment recommendations can be found at:  https://nature.berkeley.edu/garbelottowp/?p=1039.

Can coast live oak be used in a large-scale Bay Area tree planting project without exacerbating SOD?

Question: My organization is considering launching a large-scale urban tree planting project in the Bay Area, with the goal of adding one million trees to the urban forest inventory within 15 years. We are interested in coast live oak (CLO) as a major component of the effort for a number of reasons, including the ease […]

If the stump of a felled tree is left in place, can the roots to continue to grow?

A lot depends on when the tree is felled. If a tree is cut in winter, it is possible that the root system will experience an additional year of growth. What happens to the root system depends on many variables, including soil type and presence of other trees of the same species adjacent to the […]

We have old camellias and a pittosporum on our property that are healthy, but growing very close to coast live oaks. Should they be removed to help protect the oaks from SOD?

When thinking about P. ramorum dispersal, it is important to think about spread at two scales. First, the pathogen establishes itself on transmissive host leaves (e.g. California bay laurel, tanoak, redwood, rhododendron, and camellia) by moving up to several hundred meters during conducive rain events. Then, as the pathogen builds up, infection can spread from […]

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