There is no research or other observational evidence to indicate that glyphosate application increases Phytophthora ramorum infection. In mixed-evergreen and redwood forests some land managers use glyphosate to control invasive weeds, such as French broom, poison oak, and other problematic weeds. In coastal CA, these forest types contain coast live oak, California bay laurel, tanoak, and other plants susceptible to P. ramorum, but the disease is not known to spread or intensify due to glyphosate treatment.
Precautions. Always follow pesticide label instructions and consider non-pesticide alternatives to control pests. Pesticides can be injurious to humans, domestic animals, desirable plants, fish, and other wildlife if they are not handled or applied properly. Use all pesticides selectively and carefully. Follow recommended practices for the disposal of surplus pesticides and pesticide containers.