Vista Verde Community Association
Vista Verde Community Association
Vista Verde Community Association
Vista Verde Community Association
Vista Verde Community Association
Vista Verde Community Association

Sudden Oak Death (SOD)

Sudden Oak Death (SOD) is a disease that infects and kills certain oak tree species. SOD has killed many trees in Vista Verde and the surrounding area and continues to spread. This article discusses SOD and how it can be prevented. The Vista Verde/Los Trancos Woods Sudden Oak Death (SOD) Task Force was formed to help minimize the effects of SOD in our neighborhood by educate homeowners and identifying best practices. The SOD Task Force is headed by Amanda Lee and has compiled the information below.

Agri-Fos is phosphate compound formulated to stimulate growth in trees. Research has shown that about 80% of trees respond well to treatment, meaning that their defenses are stronger. Applications should be made when the tree is actively transpiring. Avoid treating trees during very hot or very cold weather.  Also, avoid applying the compound when deciduous oaks have lost their leaves or when new leaves are emerging in the spring.

To reduce the spread of SOD, a study conducted by the USDA recommends that Bay trees be separated from susceptible oaks per these specifications:

  1. Removing bay from within 2.5 m (8.2 ft.) of the trunk of a susceptible oak
  2. Extending bay foliage-oak trunk clearance to 5 m (16.4 ft.) where possible, especially in the direction(s) from which storm winds blow.
  3. Pruning low branches to obtain up to 5 m (16.4 ft.) of clearance in the lower canopy even if upper canopy bay branches are present at closer horizontal distances
  4. Eliminating poison oak climbing at canopy level within an oak or in adjacent tree within 2.5 m (8.2 ft.) of the oak trunk.

Depending on your circumstances, trimming back bays and other carrier plants/trees can be relatively easy. For the non-do-it-yourselfers we've heard recommendations for the following tree trimming contractors.

Below are tree companies recommended by neighbors for SOD treatment and tree trimming, many of whose charges are very reasonable.

By Amanda Lee

Once SOD-infested oaks, bay laurels, and other trees are taken down, that material is still capable of infecting living trees. Recommendations for disposal of SOD-infested material found on website from the “Homeowner’s Guide” ( ) are:  “In infested areas where burning is not possible, the best option is to leave infested material on site, chipping the small material (for use as ground cover) and using larger pieces for firewood. Composting can also successfully kill the pathogen, but the compost must reach temperatures that are probably not possible or practical in a home composting site. Since inoculum levels are already thought to be high in an infested site, leaving the additional inoculum from the infested plant material on site will not significantly worsen the local disease conditions.”

From Dr. Matteo Garbelotto, Forest Pathologist and Mycologist, UC Berkeley October 20, 2007

The assumption (in Dr. Cindy Russell's email below) is that massive spraying will occur, which is not the case.  Treatments are focused on individual trees and the bark applications are not broadcasted but basically carefully applied on individual trees.

Fueling a car is a lot more dangerous than an appropriate application of Pentrabark from an environmental perspective.  Because the product sticks on the target surface, it is extremely difficult for it to get into the environment.

The email I was sent takes the treatments out of context, however we will dedicate an equal amount of time to injections that do not require Pentrabark.