Bark beetles are attacking my oak. Will they kill the tree? What should I do?

Once bark beetles attack the main stem (trunk) of an oak, the tree is on its way out.  Insecticide treatments will not save it. Oak beetles are attracted to trees that are severely compromised.  They cannot attack healthy trees. The correct approach to avoid bark beetle infestations is not to apply insecticides, but rather to […]

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 […]

My pear tree was looking great. Within a week one of the limbs died and now it looks like the whole tree is dying.

It sounds like your tree is having problems providing enough water to the canopy to keep the foliage and cambium alive. If you are not watering it, that may be the problem. If you are watering it, your tree may have contracted a root disease. In that case, it is important to clear all organic […]

I have an oak tree that is leaking a dark substance 4′ up the trunk, but otherwise it looks healthy. I live in Alameda County. Do I need to be worried about sudden oak death?

Download sod map mobile and tap the risk button. If the risk shows up as high or moderate, call an arborist listed at http://www.suddenoakdeath.org/diagnosis-and-management/arborists-applicators/. If you get an insufficient data response, then see if you have any CA bay laurel trees within 20 yards of the oak. If you find any, do they have possible […]

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 […]

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