Pathologist, interrupted
Sudden notoriety for ‘Sudden Oak Death’ expert Matteo Garbelotto changed his life

By Diane Ainsworth, Public Affairs

Matteo Garbelotto Noah Berger photo

12 September 2001 | His name goes hand-in-hand with “Sudden Oak Death,” but Matteo Garbelotto didn’t plan it that way.

You might say he was a pathologist, interrupted.

On that fateful day in July 2000, his career took a sudden, unexpected turn. The rest is history.

“That phone call changed my life…dramatically,” he said. “All of a sudden, not only was there all of this attention over the spread of Sudden Oak Death, but every piece of information that I was talking about was publicized, because there was so much public attention.”

Garbelotto was about to become the University of California Extension specialist in forest pathology when he was asked to join a group of researchers trying to identify the culprit responsible for Sudden Oak Death in Sonoma Valley tanoaks. At the time, insects were thought to be responsible for the widespread mortality. Garbelotto, instead, diagnosed the problem as the likely consequence of a pathogen with the genus Phytophthora (Phy-TOFF-thoruh). Soon after, UC Davis Professor David Rizzo isolated from the dying trees a yet undescribed species belonging to Phytophthora, and Garbelotto teamed up with Rizzo to learn more about the pathogen. He had no idea then that his work would cast him into the limelight of worldwide media attention.

“I was still a post-doc at Berkeley back then, but I had been offered a job as the only UC forest pathologist at the time,” he said. “When I started working on the disease, though, it was already such a widespread problem that it was drawing a lot of attention in the press. All of a sudden I realized that literally millions of people were reading about my work. This was a major change for a forest pathologist like me who, until then, had been working mostly on relatively obscure diseases.

“At the same time, my colleague, David Rizzo at UC Davis, and I also realized that we could not wait to publish our findings either, like researchers normally do in scientific journals,” he said. “There was an urgency to disseminating the information. We had to set up new ways of getting the information out while keeping the appropriate authorities informed at the same time.

“It changed the way we work,” he added.

Rizzo and Garbelotto, who speaks with the Italian accent of his native land, used DNA sleuthing to identify the pathogen. They determined that the disease had been caused by a never-before-seen strain of fungi from the genus Phytophthora. As it turned out, a relative belonging to this 60-member group of fungi had caused the 1845 Irish potato famine, and another relative was linked to the dieback of cedar trees in Northern California and southern Oregon, as well as eucalyptus trees in Australia and oaks in Mexico, Spain and Portugal.

Next the two conducted experiments with infected potted trees, treating them with one of four chemical compounds: copper sulfate, al-fosetyl, metalaxyl or phosphonate. The diseased oaks were either injected with the chemical, had their soil drenched with the chemical compound or were treated topically. New findings for managing the spread of the disease are expected to be released in January, Garbelotto said.

“What was unusual about this situation is that I had very little experience with oak systems before this happened,” he said. “Most of the forest pathology research in this part of the world had been done on conifers in the Sierra Nevada, and obviously, this was a new disease, so it was like putting the pieces (of a puzzle) together bit by bit. But I never would have guessed two years ago that this is what I would have been working on.”

Out of necessity, Garbelotto and Rizzo learned to work closely with the media. “It was important to have findings accurately reported because we were not going through peer-reviewed journal publications to disseminate information,” Garbelotto said. “We took painstaking efforts to make sure the press understood what we were saying, and it’s really paid off.”

With many missing pieces of the disease yet to be uncovered, Garbelotto and Rizzo are hoping that Phytophthora ramorum is not discovered on plants or trees in other states. However, the latest developments in the epidemic have raised concerns among experts that Sudden Oak Death could spread to northern red oaks and pin oaks found in the Midwest and East, because those trees seem particularly susceptible.

“We haven’t found the disease outside of California and Oregon yet,” Garbelotto said. “The good news is that our latest results seem to support the hypothesis that this is a pathogen recently introduced in California. This would explain the still limited distribution of the disease, which is good news.”

The bad news, however, is that the pathogen is spreading into the East Bay and Berkeley territory.

“I went around campus and inspected the oaks and, until now, none of them had been infected,” he said. “Unfortunately, we have evidence now that the disease may be in the East Bay. I am hoping that we will start a preventive management program soon to protect our oaks.”