Brenerria quercina or Drippy Acorn is favored by heat, moisture, and insect wounding. The bacterium enters the acorn shell through puncture wounds, which a variety of insects cause during egg laying and feeding.
Phytophtera root rot is a fungal pathogen that affects many types of trees and plants. It is a soil-borne disease found on living roots that can survive for long periods of time without a host. Most often, Phytophtera is found on sites with poor draining soil and/or excessive irrigation.