Are sudden oak death preventative phosphite treatments effective on madrone?
Preventative treatments are only designed for oaks. To protect madrone, remove any California bay laurel, tanoak, or ornamental rhododendron growing nearby (30 ft around each madrone). However, be careful when doing so as disturbances often affect madrone health.
Is it safe to use tanoak chips on our property if the tanoak died from sudden oak death?
It is safe to broadcast the chips in a thin layer in an area without woody vegetation (e.g. surfaced, gravel, or grassy) and 100 feet from known SOD hosts.
How susceptible are madrones to P. ramorum/sudden oak death (SOD)?
Madrone is very susceptible to P. ramorum (pathogen known to cause SOD), and in rare occasions it may support pathogen sporulation enough to cause infection of nearby oaks. Adult madrones typically experience dieback of infected branches, but they are rarely killed by the pathogen. However, seedlings and saplings can be killed and should be removed if growing within 30 feet of oaks.
I collect and rear acorns for restoration work. How do I tell if the seedlings are healthy before outplanting?
Since there are several native diseases that may affect seedlings, the best approach is to wait at least 1 year following germination before outplanting. Symptoms to look for during this holding time include wilting and leaf spots.
If acorns came from an area with SOD, the situation is a bit more complex. At this point, we have no evidence that SOD may be present as a pathogen in oak acorns or that it may affect oak seedlings; however, “carry over” of spores that are not infecting the seedling may occur if acorns have been collected in very rainy years. While this is likely low risk, if you picked acorns in an area with high or moderate risk of SOD (use the free SODmap mobile app to determine) in a very rainy year, you could be extra cautious and treat acorns with a diluted bleach solution before germinating them.
How susceptible is Italian laurel to P. ramorum/sudden oak death?
Tests conducted on Italian laurel at the UC Berkeley Forest Pathology Laboratory indicate it is moderately to highly susceptible to P. ramorum (pathogen that causes sudden oak death), compared to California bay laurel which is highly susceptible. Based on these results, it is recommended that Italian laurels not be planted in close proximity to oaks.
What are the latest recommendations for protecting high-value oaks from SOD?
Current preventative recommendations for helping to protect high-value oak trees from sudden oak death can be found at New Recommendations for Management of Oaks.
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Where can I find more info about BMP’s?
You can find all of our recommended BMP’s at https://nature.berkeley.edu/matteolab/?page_id=3303