Human movement of infested host materials is considered the most likely means of long distance spread. Researchers are also investigating insects as possible vectors for this disease. The new Phytophthora sp. Zoospores are produced asexually in sporangia. The spores are short-lived and motile.
Zoospores can swim several feet through water or water films to infect a susceptible host.
Sporangia may also germinate and infect susceptible hosts without producing zoospores. Chlamydospores are specialized spores that allow the fungus to survive environmental extremes. Laboratory experiments have demonstrated that the SOD Phytophthora is very drought resistant. Chlamydospores of other Phythophthora species have been known to survive for 2-6 years in infected plant debris or soil. The SOD fungus prefers cool, wet conditions.