Sudden Oak Death pathogen is evolving, says new study that reconstructs the epidemic

Almost all adult tanoaks have been killed by the Sudden Oak Death pathogen in many sites around the Big Sur region in Monterey County. Despite the extreme severity of the... Click here for more information.

Berkeley - The pathogen responsible for Sudden Oak Death first got its grip in California's forests outside a nursery in Santa Cruz and at Mt. Tamalpais in Marin County before spreading out to eventually kill millions of oaks and tanoaks along the Pacific Coast, according to a new study led by researchers at the University of California, Berkeley. It provides, for the first time, evidence of how the epidemic unfolded in this state.

"In this paper, we actually reconstruct the Sudden Oak Death epidemic," said Matteo Garbelotto, UC Berkeley associate extension specialist and adjunct professor, and principal investigator of the study. "We point to where the disease was introduced in the wild and where it spread from those introduction points."

The study, scheduled to appear later this month in the online early edition of the journal Molecular Ecology, also shows that the pathogen is currently evolving in California, with mutant genotypes appearing as new areas are infested. These findings suggest that movement of infected plants between different regions where Sudden Oak Death is established should be minimized, said Garbelotto.

These tanoaks were killed by the Sudden Oak Death pathogen on Mt. Tamalpais in Marin County, near one of the sites where the exotic pathogen was first introduced in California.... Click here for more information.

Garbelotto will present these findings today (Wednesday, April 16) at the annual meeting of the California Oak Mortality Task Force, a coalition of research institutions, public agencies, non-profit organizations and private industry formed to coordinate management, research, outreach and policy efforts surrounding Sudden Oak Death disease in California. Garbelotto is a member of the task force.