Caused by a water mold named Phytopthora ramorum. Literally translated, Phytophthora means Plant destroyer. It is an aggressive pathogen that affects the plant vascular system.
The disease is spread by wind and raindrops, generally in late spring. Host trees such as bay laurel and tanbark oak located nearby are common sources of pathogen inoculum. Warm, wet springtime rain events significantly contribute to the activation and spread of this disease. It is expected that the late winter/spring rainfall during the years 2023 and 2024 are going to trigger the next significant SOD outbreak. The pathogen can be present in a tree for up to 2 years before it exhibits symptoms. It is recommended that high value trees are selected and put on a pathogen protection program.
Management consists of annual bark sprays using phosphite based material combined with a bark penetrant. Treatment protocol calls for two initial applications the first year, followed by annual treatments.
Sudden Oak Death
Tree Solutions recommends a comprehensive approach to SOD management:
1. Initial site analysis: tree identification with SOD susceptible species inventory, inspection of host plants in proximity of oaks, history of infections and oak mortality on the property and in the geographic area.
2. Identification of potential trouble spots – host plants (bay laurel tree, tanbark tree) in the proximity of susceptible oak species. Bay-laurel removal and pruning plan.
3. An initial Phosphite application in spring (March/April) or fall (October/December).
4. A follow up application within approximately six months of the first.
5. Annual applications in the same season as #4, whether spring or fall.
6. Stem injection applications to be done in spring season when soil moisture content is good, or by specific recommendation, taking into account the site specifics, soil moisture availability from early rains, groundwater or irrigation.
7. Identification of other tree management issues and stress factors with a plan for needed corrections to address site conditions and pest control
tree structural integrity and hazard issues
ree root collar disorders
pest control – oak moth caterpillars, gold spotted oak borer, other oak bark beetles, pests and diseases
site conditions review for optimum plant health care - drainage, soil grade, fertility control import/export of plant materials