How Phytophthora ramorum Is Spread
Like other Phytophthora species, Phytophthora ramorum can spread over short and long distances. It spreads over short distances by movement of:
- Spores in plant material, soil, potting media, and water
- Sporangia on air currents
- Spores on muddy shoes, tires, and equipment.
Nursery plants infected with Phytophthora ramorum have carried the pathogen across much of the United States.
Researchers found that Phytophthora ramorum can be carried by hikers after they have walked through an infested area. Before leaving a Phytophthora-infested area, careful hikers clean their shoes and spray them with a disinfectant such as Physan 20 or 10% bleach.
Photo by S. Tjosvoid.