Posts Tagged: Matteo Garbelotto
With Californians sheltering in place to stop the spread of new coronavirus COVID-19, the annual citizen science project to map sudden oak death disease has been redesigned to ensure the safety of participants. The first in a series of SOD blitzes of 2020 will be April 11 in Napa. The events are free.
“We have been able to redesign the 2020 SOD Blitzes to make them a safe and legal activity that allows volunteers to exercise outdoors, and this powerful citizen science program will help us protect our forests' health,” said Matteo Garbelotto, UC Cooperative Extension forest pathology specialist and adjunct professor in the Department of Environmental Science, Policy and Management at UC Berkeley and event organizer.
Sudden oak death disease has killed more than 50 million of the state's iconic oaks and tanoak trees between Humboldt County and Monterey County, threatening survival of several tree species. In 2019 alone, 1 million tanoaks succumbed to sudden oak death, according to 2019 tree mortality data released by the U.S. Forest Service.
“The presence of new SOD strains is alarming and the SOD blitzes are the best, if not the only, program to intercept them before they spread,” Garbelotto said.
SOD Blitz volunteers will register online and take the training online at www.sodblitz.org to learn how to identify SOD symptoms and to carefully collect symptomatic leaves from California bay laurels and tanoaks. Collection and survey materials, which have been prepared in a sterile environment, will be picked up by participants at a local SOD Blitz station conveniently located near a parking lot. They can return samples to the same SOD Blitz station or by mail.
As citizen scientists, volunteers should focus on following safety guidance as well as adhering to research protocols. Social distancing – at least 6 feet away from other volunteers – and clean “housekeeping” rules will be strongly enforced when picking up or returning materials and during leaf collection.
For parents who are home schooling their children, this is an activity that the family can do together.
Garbelotto encourages tree care specialists to participate in the SOD blitzes.
“Besides offering free bay laurel and tanoak tests for their clients, we now offer tree care professionals free enrollment in UC Berkeley Forest Pathology Laboratory's OakSTePprogram, which allows them to test oaks for SOD infection,” Garbelotto said.
For more information, visit www.treefaqs.org or email the organizer of the SOD Blitz in your community (See schedule below).
Sudden Oak Death Blitzes 2020
All collection materials will be provided, but participants need a mobile phone or GPS device to install the free SODmap mobile app.
New format due to COVID-19
1. Training (30 minutes) and sign-up (5 minutes) must be done online at www.sodblitz.org before collecting the sampling materials at the SOD Blitz Stations in the locations specified below. Please sign up before you start the survey, and preferably when you take the online training.
2. Once at your local SOD Blitz Station you can pick up one or two collection packets following the social distancing rules of the State of California clearly specified in the online training. Stay at least 6 feet from other collectors. Bring your own pencil. Each packet allows you to sample 10 trees. Do not pick more unless you discussed it with the organizer.
3. Before you start the survey, make sure you have downloaded the free App “SODmap mobile” to determine the exact location of the trees you sample.
4. Each SOD Blitz has a start and end date, including the hour. You can pick up materials at the start time and you have to return your samples and any unused collection materials by the end date and cutoff time.
5. You can sample private properties with the owner's permission, alongside public roads and in parks or open spaces that are open to the public.
6. If you have any questions, please email your local organizer. Thank you so much for your participation.
Saturday, April 11 at 10 a.m. to Tuesday, April 14, 10 a.m.
SOD Blitz Station located on front porch of the Napa County Agriculture Commissioners Office Building 1710 Soscol, Napa
Please mail samples to UC Berkeley using the preprinted mail labels and postage included in each packet.
Contact: Bill Pramuk email@example.com
For a schedule of SOD Blitzes at other locations, visit https://nature.berkeley.edu/matteolab/?page_id=5095.
“Two new dangerous SOD strains are at the doors of our forests,” said Matteo Garbelotto, UC Cooperative Extension forest pathology specialist in the Department of Environmental Science, Policy and Management at UC Berkeley. To assess the movement of SOD, he has mobilized citizen scientists for what he calls “SOD blitzes.” The first in a series of SOD blitzes of 2020 will be April 11 in Napa.
“We had some great results last year and participation continued to be good after 13 years of SOD blitzes,” Garbelotto said.
In Sonoma County, the 2019 SOD infection rate doubled that of 2018, and in Napa County, SOD detection was four times higher than the previous year. In the East Bay, between Richmond and San Leandro, SOD infection spiked – from 1% to 12%. The SOD infection rate tripled – from 6% to 18% on the western slopes of the Santa Cruz Mountains in San Mateo County.
As the disease expands its path of forest destruction, the UC Cooperative Extension scientist says more volunteers are needed to sample trees.
“The disease is moving to new counties outside of the current area of infestation,” Garbelotto said. “Even in our Bay Area neighborhoods, SOD of 2019 is not the same SOD of 10 years ago: different distribution, new local outbreaks, and new hosts are emerging, as the disease becomes more and more established in its new home.”
Garbelotto sees the SOD blitzes as the only hope for early detection of the new SOD strains.
“If these new strains arrived and spread in our forests, they could deliver a fatal blow to our forests,” he said. “By collecting symptomatic plant material in their neighborhoods, volunteers will make the most significant contribution possible to intercept these strains.”
Volunteers are taught to identify SOD symptoms and to carefully collect symptomatic leaves from California bay laurels and tanoaks. Participants in the SOD blitzes will be asked to quantify their efforts to stop SOD to show public interest in saving oaks and tanoaks when applying for funds to defeat the tree-killing disease.
Garbelotto is encouraging tree care specialists to participate in the SOD blitzes.
“We have enhanced the benefits for tree care professionals who participate in the blitzes,” Garbelotto said. “Besides offering free bay laurel and tanoak tests for their clients, we now offer them free enrollment in UC Berkeley Forest Pathology Laboratory's OakSTeP program, which allows tree care professionals to test oaks for SOD infection. It could be enormously beneficial to everybody.”
Sudden Oak Death (SOD), a serious exotic tree disease, threatens the survival of tanoak and several oak species in California. Currently, SOD infects trees in 14 coastal California counties, from Monterey to Humboldt. The disease, which was estimated to have killed over 50 million oaks and tanoaks over two decades, has changed the coastal forests composition in Northern California and Southern Oregon.
Though SOD occurs in patches, the overall infection area continues to grow with each passing year. Researchers had previously discovered that Phytophthora ramorum, the pathogen that causes SOD, most often spreads on the leaves of infected California bay laurel and tanoak. Forest managers can use proactive methods for controlling the disease — including sanitation, chemical treatments, and the targeted removal of bay trees — but such tools are preemptive in nature, only useful before oaks and tanoaks are infected. Timely detection of the disease in these species is therefore critical to slowing the epidemic.
With this in mind, UC Berkeley joined with over 30 local organizers in 2019 to assemble 25 SOD Blitzes staffed by trained volunteers. More than 400 volunteers were taught to identify SOD symptoms and to carefully collect symptomatic leaves from California bay laurels and tanoaks. Armed with this training, the teams surveyed 16,227 trees across 16 California counties, collecting approximately 9,000 leaves from 1,732 symptomatic trees. Samples were sent to the UC Berkeley Forest Pathology and Mycology Laboratory for processing and analysis.
The benefits of SOD Blitzes are becoming increasingly clear. Importantly, they educate the community about Sudden Oak Death, getting locals involved in detecting the disease while creating detailed maps of infected areas. Analyses of these maps help forest managers figure out where proactive measures, such as chemical treatments or tree removal, most effectively stop an infestation. All results from the data collection are made publicly available on SODBlitz.org, SODMap.org, and on the SODmap mobile app available at the Apple Store and at Google Play. (Results can also be accessed directly on the UC Berkeley Forest Pathology and Mycology Laboratory website.)
Using the app allows anyone to estimate the risk of oak infection, specific to their current location. While standing next to a tree of interest, a person can tap the app's “RISK” button and determine whether an oak is in danger of contracting SOD. In addition, results meetings and treatment training workshops will be held for the public in various Bay Area locations during fall 2019.
Matteo Garbelotto, UC Cooperative Extension specialist and adjunct professor in the Department of Environmental Science, Policy, and Management, has led the SOD Blitzes for 12 years. The program enrolls approximately 500 volunteers yearly to canvas California woodlands for symptoms of SOD. Results of the surveys are made available nearly in real-time, immediately after completion of the lab analysis.
“We estimate that as many as two to three million people may have accessed the SOD Blitz results to determine whether trees on their property may be at risk,” Garbelotto said. “This is a huge success and shows the great societal value that citizen science has, and it highlights the importance of collaborating with volunteers on issues that are relevant to safeguard trees that are an important part of California's natural heritage.”
2019 SOD Blitz Results
Across the state, the number of trees infected with SOD, along with the estimated SOD infection rate, has almost doubled since 2018. In some areas, infection rates were as much as 10 times higher than the previous year. These results suggest that the overall risk of oak infection by SOD is rising.
Spikes in the estimated SOD infection level at certain locations are particularly noteworthy; for example, from 1 to 12 percent in the western part of the East Bay between Richmond and San Leandro, including distinct outbreaks discovered in El Cerrito, Kensington and Berkeley. The western slopes of the Santa Cruz Mountains in San Mateo County have also seen an increase in SOD infection rate (from 6 to 18 percent), which may make safeguarding recreational venues and ecologically important forest sites more difficult. In Sonoma County, the 2019 SOD infection rate was approximately double that of 2018, and in the same timeframe, Napa saw a fourfold increase in detection. Peninsula towns between Redwood City and Los Altos Hills had a very high infection rate (21.6 percent) with an expansion of outbreaks to the east and north.
Some additional key results that came from the 2019 SOD Blitzes include:
- Two tanoaks were positive for SOD in a state park east of Crescent City in Del Norte County, marking the first report of SOD for the county. This was an important finding because, until 2019, Del Norte was the only county free of the disease in the area between the vast California infestation and the Southern Oregon outbreak. The SOD Blitz finding does not have immediate implications for regulations, but regulations will be imposed once CDFA can confirm the finding.
- An extensive survey of San Luis Obispo failed to identify SOD; however, multiple trees were found to be infected in the southernmost canyon of Monterey County. Previously, this canyon had only provided positive findings from water monitored by UC Davis scientists, but not from trees.
- Although Humboldt County has a few significant SOD outbreaks, and Trinity County has a marginal SOD outbreak in its southwestern border, SOD Blitzes in tribal lands in Humboldt and Trinity counties did not yield any SOD positives.
- San Francisco parks, including the Presidio, were negative for a second year in a row, suggesting that disease management practices have been successfully implemented in the area.
- Several cases were identified in the northern neighborhoods of the City of Napa. No positives had been found in this area since 2011.
- All isolates of the pathogen belonged to the NA1 lineage, which is more easily treated and common in the region. This is good news because of uncertainty about the potential virulence of the EU1 lineage recently discovered in Oregon forests.
A sampling of other noteworthy 2019 SOD Blitzes results follow. More results are available on the websites and app:
- The first infected Bay laurel was identified a few miles east of the town of Mendocino (Mendocino County) along the Comptche-Ukiah Road.
- Multiple SOD positive trees were identified between Guerneville and Duncan Mills in Sonoma County. The Russian River area has long been known to be affected by SOD.
- An outbreak was identified in southwestern Petaluma, while infestations were confirmed in Bennett Valley, Santa Rosa and east of Rohnert Park.
- Multiple infestations were identified in Marin County, including the ones northeast of San Rafael, Larkspur, Woodacre, Mount Tamalpais, Marin City and north of Inverness.
- In the Peninsula, SOD was identified in Burlingame Hills, northern Woodside, Emerald Hills, Palomar Park, Portola Valley. In Los Altos Hills and Loyola, SOD positive trees were detected both East and West of Interstate 280. An outbreak was detected west of Saratoga.
- High levels of infection were identified all along Skyline between Bear Gulch Road and Highway 17, and on the western slopes of the Santa Cruz Mountains between Skyline and Pescadero.
- SOD was confirmed between Felton and Santa Cruz and between Aptos and Santa Cruz.
- In Monterey County, the chronic Big Sur outbreak was once again confirmed to be active, while the disease appeared also in drier areas of the Carmel Valley, where it had been absent for a few years.
The SOD Blitz program was funded in part by the U.S. Forest Service's State and Private Forestry Organization and by the Midpeninsula Regional Open Space District. It was also made possible by a collaboration with the California Native Plant Society, CalFire, the Humboldt/Del Norte and Sonoma County UC Cooperative Extension, the Sonoma County UC Master Gardeners, the U.S. National Parks, California State Parks, the East Bay Regional Parks, the San Francisco Public Utility Commission, Mid-Pen Open Space, the UC Santa Cruz Arboretum, Santa Cruz Open Space, the Santa Lucia Conservancy, the Karuk and Hoopa Nations, the Mendocino Botanical Garden, the City and County of San Francisco Parks and Recs Office, and Strybing Arboretum. Many individuals, who have generously devoted their time and efforts, have been pivotal for the existence and success of the program.
- Matteo Garbelotto: Leading the citizen science contagion
- First known cases of sudden oak death detected in Del Norte County
- SOD Blitz Project
- SOD Blitz map of results and summary table
In 2014, plant biologists with the California Department of Agriculture reported an alarming discovery: native wildflowers and herbs, grown in nurseries and then planted in ecological restoration sites around California, were infected with Phytophthora tentaculata, a deadly exotic plant pathogen that causes root and stem rot.
While ecologists have long been wary of exotic plant pathogens borne on imported ornamental plants, this was the first time in California that these microorganisms had been found in native plants used in restoration efforts. Their presence in restoration sites raised the frightening possibility that ecological restoration, rather than returning disturbed sites to their natural beauty, may actually be introducing deadly plant pathogens, such as those related to Sudden Oak Death, into the wild.
New work by a UC Berkeley team in the College of Natural Resources shows for the first time just how widespread and deadly the threat of pathogens from restoration nurseries may be.
The team surveyed five native plant nurseries in Northern California and found that four harbored exotic, or non-native, Phytophthora pathogens. Strains of the pathogens from native plant nurseries were shown to be at times more aggressive than strains found in the wild, and some of them are rapidly developing resistance to the fungicides that can be used to control them, the researchers found.
Working with restoration nurseries around the state, the researchers showed that new management techniques, coupled with new methods for detecting pathogens, can help these nurseries limit the spread of exotic pathogens.
"Some of these restoration projects cost tens of millions of dollars, but of course their actual value is much higher, because of the wealth of services healthy natural ecosystems provide, including supporting animal and plant biodiversity, providing good water and air quality, and enjoyable recreation sites," said Matteo Garbelotto, UC Cooperative Extension specialist and adjunct professor of environmental science, policy and management at UC Berkeley.
"Such services are highly diminished in ecosystems affected by exotic plant diseases, while water runoff and erosion, the establishment of exotic plants and animals, and even hotter wildfires may increase in conjunction with disease outbreaks in natural ecosystems," Garbelotto said.
Pathogens evolve to outwit fungicides
Bacteria that make humans sick are constantly evolving to resist the antibiotics designed to fight them, and resistance to fungicides has been documented in microbes causing diseases in agricultural plants. Garbelotto and his team wanted to know if the widespread use of fungicides in in native and ornamental plant nurseries could also accelerate the development of fungicide-resistance in plant pathogens.
Their research was spurred in part by their discovery of a new strain of the Sudden Oak Death pathogen in Oregon forests that is highly tolerant of a fungicide commonly known as phosphite, one of the main weapons used against plant parasites in the wild because its application does not cause any known negative environmental side effects.
Together with a group of New Zealand researchers, they decided to study fungicide resistance of Phytophthora -- a genus of plant pathogens that can case lethal cankers and root rot -- to two important fungicides, including phosphite.
The researchers gathered numerous samples of Phytophthora from 11 species present both in forests and plant nurseries. They then tested the sensitivity to phosphite of multiple individuals per species.
While most of the species tested were overall still sensitive to phosphite, strains of four species were able to resist the effects of the chemical, the researchers report in PLOS ONE. These include Phytophthora ramorum, the parasite behind Sudden Oak Death in North America and Sudden Larch Death in Europe, and Phytophthora crassamura, a species first discovered recently by the same UC Berkeley researchers in native plant nurseries and restoration sites in California.
Some strains within each of these four species, although genetically almost identical to strains still susceptible to phosphite, were resistant to it. The presence of chemical tolerance or chemical sensitivity when comparing nearly genetically identical strains suggests that the development of resistance occurred relatively recently, perhaps in response to the widespread use of phosphites in native and ornamental nurseries, Garbelotto said.
"These pathogens can be literally flooded with these chemicals in plant production facilities, and at the beginning of the study, we hypothesized that in such predicaments these pathogens would be forced to evolve resistance" Garbelotto said. "Indeed, our hypothesis was correct, and we found that some of them evolved the ability to tolerate exposure to phosphite."
While phosphite can still help to spur a plant's immune system, this may not be enough to quell the spread of the disease, Garbelotto said.
"By pressuring these pathogens to evolve resistance to phosphites, we are effectively taking out phosphite as a potential tool to manage these disease outbreaks," Garbelotto said. "Furthermore, the ability to quickly develop tolerance to a fungicide may be an indication these pathogens can adapt quickly to new environments. Thus, they may become formidable invasive organisms, infesting larger swaths of natural areas and causing significant disease and mortality of essential native flora."
A widespread - but reparable - problem.
Since the first discovery of Phytophthora in California restoration sites, research by the UC Berkeley team and others have traced the deaths of wild trees and plants back to strains of the pathogen originating in native plant nurseries, rather than strains already found in the wild. However, few studies have documented just how prevalent the problem is.
In a recent study published in the journal Plant Pathology, UC Berkeley researchers examined 203 individual plants across five restoration nurseries in California and found that 55 of the plants were infected with Phytophthora.
"We were able to prove that this is a widespread problem in California," Garbelotto said. "Most of the stock that they used is infested, and the levels were very high. For some species more than 50 percent of the plants we tested were infected."
The team then worked with the infected nurseries to implement new best management practices to try to limit the spread of disease without the use of phosphite or of other fungicides. These simple guidelines, which included more careful management of water runoff and soil to reduce cross contamination, reduced the prevalence of disease to nearly zero a year after implementation.
"We were able to prove that after a year of following the guidelines, those facilities were clear of pathogens, and other facilities that did not follow the guidelines still had the pathogens," Garbelotto said. "As a result of these findings, people are now putting a lot of money and effort into making sure that the plants are clean, by following similar guidelines and by making sure that no fungicides are used to avoid the development of resistance."
Co-authors on the PLOS ONE study are Shannon Hunter of the University of Waikato in New Zealand and Nari Williams, Rebecca McDougal and Peter Scott of Forest Protection in New Zealand. Co-authors on the Plant Pathology study are L. Sims of UC Berkeley and S. Tjosvold and D. Chambers of the University of California Cooperative Extension.
This research was supported by the Endemic and Invasive Pests and Diseases Strategic Initiative of the University of California, Agriculture and Natural Resources; and by the San Francisco Public Utilities Commission in collaboration with the U.S. Forest Service (Region 5).
Overall, 3.5 percent of the trees (based on those areas sampled during the blitzes) were found to be P. ramorum positive, a threefold drop from 2017. Yet, in San Mateo, Santa Clara and Santa Cruz counties, infection levels were estimated to be as high as 19 percent, followed by 12.7 percent in the East Bay.
"Oaks and tanoaks were infected last year and will be showing symptoms such as bleeding in the stem and canopy drying this year and in the next two years to follow. Hence, despite a reduction of SOD infection on leaves of California bay laurels and leaves of tanoaks in 2018, we can expect a sharp increase in oak and tanoak mortality in 2018, 2019 and 2020."
Notable outbreaks were detected in Alameda (El Cerrito and Oakland urban parks, San Leandro, Orinda, Moraga), Marin (Novato, Day Island, Woodacre, Sleepy Hollow, McNears Beach, China Camp State Park, north San Rafael, Tiburon Peninsula, east and west peak of Mt. Tamalpais, Marin City), Mendocino (south of Yorkville), Monterey (Carmel Valley Village, Salmon Creek Trail in southern Big Sur), Napa (east Napa city), San Mateo (Burlingame Hills, west of Emerald Hills and south of Edgewood Rd, Woodside ), Santa Clara (Los Altos Hills, Saratoga, Los Gatos, along Santa Cruz Co border), Santa Cruz (along the Santa Clara Co border, Boulder Creek), and Sonoma (near Cloverdale, east and west of Healdsburg, west of Windsor, east of Santa Rosa, west of Petaluma) counties.
Several popular destinations where P. ramorum was found positive during the 2017 Blitz were negative for the pathogen in 2018, including Golden Gate Park and the Presidio of San Francisco, the UC Berkeley campus, and Mount Diablo State Park. Samples from San Luis Obispo and Siskiyou counties were also pathogen-free as were those from the southern portion of Alameda County.
“It is encouraging that SOD has yet to be found in the forests of California's northern-most counties, San Luis Obispo County and southern Alameda County,” said Garbelotto.
“It is also encouraging to see that despite its continued presence in the state for more than 20 years, SOD infection rates drop during drier years,” he said. “However, in 2018, we identified a number of communities across several counties where significant outbreaks were detected for the first time, and the Salmon Creek find in Monterey County is the southernmost positive WUI (wildland-urban interface) tree detection ever. Until the 2018 Blitz, only stream water had been found positive in the Salmon Creek area. We encourage everyone in affected counties to look at the Blitz results online and to attend one of the fall workshops to learn how to protect their oaks from SOD.”
Citizen-science SOD Blitz workshops
SOD Blitz Workshops are being held this fall in Santa Rosa (Oct. 10), Portola Valley (Oct. 16) and Berkeley (Oct. 17). The trainings will discuss Blitz results and recommendations for protecting oaks in the WUI. Workshops are intended for the general public, tree care professionals and land managers (see www.sodblitz.org for details). Two International Society of Arboriculture continuing education units will be offered at each training. Data collected from the Blitz (both positive and negative samples) have been uploaded to the SOD Blitz map (www.sodblitz.org ) as well as to SODmap (www.SODmap.org) and to the free SODmap mobile app, which can serve as an informative management tool for people in impacted communities.
Twenty-five SOD Blitz surveys were held in 2018 in the WUI of 14 coastal California counties from the Oregon border to San Luis Obispo County and included three tribal land surveys. The 304 volunteers surveyed approximately 13,500 trees and submitted leaf samples from over 2,000 symptomatic trees to the Garbelotto lab for pathogen testing.
SOD Blitzes are a citizen science program, which train participants each spring to identify symptomatic tanoak and California bay laurel trees in the WUI and to properly collect samples in the interest of generating an informative map of P. ramorum disease symptoms over time. Samples are tested for the presence of the pathogen at UC Berkeley and results are posted electronically each fall. Now in its eleventh year, the SOD Blitz program is one of the first in the world to join researchers and volunteers in a survey for a tree disease.
SOD Blitz surveys were made possible thanks to funding from the US Forest Service State and Private Forestry, Midpeninsula Regional Open Space District, and the PG&E Foundation. The Blitzes were organized by the UC Berkeley Garbelotto lab in collaboration with the National Park Service, Presidio Trust, San Francisco Public Utilities Commission, Midpeninsula Regional Open Space District, Save Mount Diablo, Land Trust of Santa Cruz County, East Bay Regional Park District, Santa Lucia Conservancy, Sonoma State University, UC Santa Cruz Arboretum, Los Padres National Forest, City and County of San Francisco Department of Recreation and Parks, UC Berkeley Botanical Garden, and California Native Plant Society.
For information on the status of P. ramorum/SOD tree mortality in California wildlands, see the US Forest Service 2018 Aerial Detection Survey results at https://www.fs.usda.gov/detail/r5/forest-grasslandhealth/?cid=fseprd592767.
For more information on the SOD Blitzes, visit www.sodblitz.org or contact Katie Harrell at (510) 847-5482 or firstname.lastname@example.org. For more information on Sudden Oak Death and P. ramorum, visit the California Oak Mortality Task Force website at www.suddenoakdeath.org or contact Harrell.