When treating large oak trees with phosphonate, is it more effective to topically apply or inject the material?

Injections may be better for large trees with a regular shape, while topical applications may be better for large, irregular, gnarly trees.

What temperature range is acceptable for treating oak trees with phosphonate?

In order to obtain maximum efficacy with oak phosphonate treatments, minimum temperatures should not be below 50 ºF. Maximum daytime temperatures should be higher than 60 ºF, but not exceed 85 ºF.    

Do azomite fertilization and lime wash treatments help control SOD?

Based on the study published by the UC Berkeley Garbelotto lab in California Agriculture (http://nature.berkeley.edu/garbelotto/downloads/calag2009.pdf), azomite and/or lime washes alone are not effective in controlling SOD.

Will the spray application for SOD prevention be updated like the injection application was?

While phosphonate injections to help control SOD are now recommended once every 2 years, spray applications should still be applied to the bark of oak trees annually.

Does phosphonate act as a vaccine, keeping trees from getting SOD?

Phosphonate is only intended to be used on trees that do NOT have sudden oak death (SOD). Once a tree is infected, it is of no use. It helps to boost the tree’s own immunity system against the pathogen. So, if a tree is very susceptible to P. ramorum (the pathogen that causes SOD), then […]

Are there any P. ramorum-resistant coast live oaks or tanoaks commercially available?

Research has identified coast live oak individuals that may be somewhat resistant to SOD, possibly because of the presence of some chemicals in the bark and phloem.  However, there is no information yet on how genetics and the environment may affect this trait. Tanoak has some mother trees that produce SOD-tolerant seedlings and some that […]

Can I apply phosphonate to my oak trees to help prevent SOD or do I need a professional?

Yes, you can apply phosphonate to your oak trees to help protect them from sudden oak death. You can find it in many Bay Area garden supply stores. If you apply it topically to the bark, you will also need the surfactant Pentra-Bark® and you will need a sprayer. If you choose to inject it, […]

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.

Are there any treatments available for an oak with Armillaria (oak root fungus)?

Once an oak has the oak root fungus Armillaria (often due to excessive watering),  most treatments will be ineffective. Be sure the base of the tree is free of mulch and other organic debris and slightly expose the root system at the root collar. While fertilizing may not help, try using one bark application of […]

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