How is Phytophthora Canker treated?

The treatment for Phytophthora Canker is applied directly to the bark at and surrounding the site where the canker is showing signs/symptoms. The treatment has additional chemicals added to it that allow it to be absorbed by the tree directly into the bark. It will not wash off unless you soak the trunk with high pressure water from a garden hose or irrigation system right after it was applied.

The rain that day or even the day after will not affect the application.