Smith described as icon and heroine for work in advancing wine grape production
A scientist first and foremost, Rhonda steadily emerged as Sonoma County's resident expert on all things wine grape during her nearly 34 years as the viticulture advisor for the University of California Cooperative Extension. Over the decades, she used her scientific know-how, meticulous research methodology and incredible work ethic to advance wine grape production in Sonoma County.
She cultivated real working relationships with growers and vineyard managers during her time setting up field trials and collecting data in vineyards throughout Sonoma County. As the years rolled by, she earned the respect and admiration of grape growers who wonder what they will do without her as she leaves her longtime post and heads into retirement.
“Rhonda Smith became a true icon in Sonoma County viticulture for her timely research and her effective way of communicating valuable information to the wine grape industry,” said grower Bob Dempel of Santa Rosa.
Tito and Janet Sasaki who farm wine grapes in the Sonoma Valley are among the growers who have benefited from Rhonda Smith's dedication to the wine grape industry. The Sasakis said Rhonda is continually studying the latest developments in viticulture science but is always ready to be in the field to help growers – often at a moment's notice when a new problem crops up.
“Rhonda Smith is the quiet heroine of the vineyards in Sonoma County. She has been the family physician of Sonoma County vines for more than three decades,” said Tito Sasaki, past president of Sonoma County Farm Bureau and a longtime agriculture industry leader. He marvels at how Rhonda has managed the challenges of raising a family while coming to the rescue of growers facing problems like red blotch virus, vine mealybug, Pierce's disease and many other threats.
“Her serene and relaxed demeanor conceals the rock-solid strength of her dedication to others,” Tito said.
Said Janet Sasaki, “Rhonda is the hardest working person I know. My friends and I have been working with her since 1989. No vineyard is too small for her to take an interest in the problem. She is very respected by everyone in the wine grape industry.”
For her part, Rhonda, who is 66 and the mother of two grown children, said she has been fortunate to work in a field she loves, particularly, being able to focus so much of her time and energy on plant pathology, which has intrigued her since her days as a student at the University of California, Davis. She was inspired by professors and Cooperative Extension farm advisors who used scientific research to find ways to combat the diseases that were impacting agriculture and causing economic losses to farmers.
Becoming the viticulture advisor in Sonoma County gave her the opportunity to do the research she loved while providing the best possible opportunities for growers to thrive and produce the world class wines that have made Sonoma County famous. She said her goal has always been to assist the industry in successfully navigating the delicate balance between grape quality and economically acceptable crop yields – the essential combination to prosper as a premium grower of wine grapes.
“It's been fun and rewarding to be part of the Sonoma County wine industry for so many years,” said Rhonda, a resident of Windsor. Over the years she has been recognized with awards and accolades for her many contributions. In 2008 the Harvest Fair board of directors named her “Friend of Agriculture,” noting her hard work “to keep agriculture part of the Sonoma County landscape.”
Rhonda arrived in Sonoma County in 1986 to fill the UCCE viticulture advisor position held for many years by Robert Sisson, who had helped orchestrate Sonoma County's transition to premium varietals like chardonnay and cabernet sauvignon. It was a move that took Sonoma County from jug wine producer to a celebrated player on the world's wine stage.
Realizing the importance of maintaining quality and economic viability for Sonoma County's most important farming endeavor, Rhonda rolled up her sleeves and plunged into research and grower outreach to assist the viticulture industry as it faced continued new threats.
Shortly before starting as viticulture advisor, there was a crisis: vineyards throughout Sonoma and Napa counties were in decline, displaying lackluster vigor and sharp drops in yields. The culprit was phylloxera, a tiny insect that feeds on grapevine roots.
At that time, more than half the vineyard acreage in Sonoma and Napa counties was planted on a rootstock that had become susceptible to the insect pest. As a result, the majority of the vineyard acreage had to be replanted once severely infested with phylloxera.
Growers desperately needed a path forward. Rhonda and other scientists from UC Davis launched trials to evaluate the performance of alternative rootstocks for vineyards in the North Coast counties.
Through her rootstock trials, Rhonda was able to inform growers of the suitability of specific rootstocks in sites with heavy, cracking clay, wet soil conditions and high nematode populations.
Stephanie Larson, who is the director of UCCE in Sonoma County, said Rhonda Smith's targeted work on so many important issues epitomizes what a UCCE advisor should be – diligent and dedicated to finding solutions to growers' problems and channeling information and research from the University to the field. She said Rhonda's work spanned the spectrum from identifying the best rootstocks to coping with powdery mildew.
“Rhonda was a solid advisor who was extremely dedicated to the wine grape industry. She held UCCE Sonoma County Grape Day each year, without exception since 1987. Grape Day provided growers the most current information on issues such as pests, water, diseases, clones and rootstocks,” said Larson.
For 20 years Rhonda also coordinated the Sonoma County Vineyard Technical Group's nine monthly programs each year, working collaboratively with grower-members to select topics and speakers – including those from out of state - to bring research-based information that addressed farming practices and pest management applicable to the local industry.
“Throughout her career, Rhonda collaborated with state and local regulatory and resource agencies to provide expertise on issues that directly affect wine grape production,” Larson said.
Larson said Rhonda's retirement leaves a huge gap in viticulture knowledge and expertise for the industry. Unfortunately, she said, because of the state's current budget crisis, the UC Division of Agriculture and Natural Resources will not be filling Rhonda's position. But Larson said the University would entertain a discussion with the wine industry to hire a new viticulture advisor if the industry would fund half the cost of the position. She said there must be a five-year commitment for the funding.
Rhonda, who came from a military family, grew up in El Dorado Hills outside of Sacramento. She didn't have a farming background but early on knew she wanted to work outside, not in an office cubicle, after spending time at her uncle's walnut and hog ranch in Galt.
She went to UC Davis and in 1977 earned a bachelor of science degree in plant science, with an emphasis in plant pathology. In 1983 she completed a master's degree from Davis in horticulture, with an emphasis in viticulture.
Before taking the viticulture position in Sonoma County, she worked as a research associate for UC Davis, UCCE and the Department of Food and Agriculture in various parts of California.
Rhonda said her work in Sonoma County was more expansive and productive because of the tremendous cooperation of growers, vineyard managers and wine industry executives who provided vineyards and support for the field trials she conducted. She worked with dozens of vineyard industry professionals during her long career, often, bonding over mutual interests in chardonnay clones or vexed by the vagaries of Pierce's disease, caused by a bacterium spread by the blue-green sharpshooter.
Mark Lingenfelder, who was at Chalk Hill Estate Winery for many years, worked with Rhonda on a number of projects including chardonnay clonal studies and trials investigating the efficacy of a plant growth regulator to improve fruit set. Lingenfelder said because of Rhonda's expertise and professionalism it was a pleasure cooperating and collaborating on research trials that yielded valuable information that was shared with the viticulture industry.
“I was always amazed by Rhonda's energy, persistence and meticulous attention to detail. But she was not only a dedicated and tireless researcher. She was also a friendly, knowledgeable and patient advisor who was always incredibly generous with her time whenever I turned to her for advice,” said Lingenfelder. “We've had some great long conversations.”
Dana Grande, grower relations manager at Jordan Vineyard & Winery in Healdsburg, said she first met Rhonda Smith in 1994, a time when there were few women working in the viticulture industry.
“At that time, you could count the number of women in Sonoma County viticulture on one hand. Our relationship has always been one of mentorship – her to me - and it encompassed not only viticulture expertise, but how to carefully balance the career/mom life,” said Grande.
From 2002 to 2008 Grande worked with Rhonda on a study of berry shrivel in a cabernet sauvignon block, which was known as “Rhonda's Rows,” at Jordan. The collaboration forged a long, lasting relationship and mutual respect between the two viticulture professionals.
“I can't imagine what Sonoma County viticulture will look like without Rhonda Smith,” said Grande. “I and many others have relied on her advice, experience, and expertise for decades.”
In retirement, Rhonda plans to take a deep breath and then catch up on projects around the house and do some traveling. She will also have more time to spend with husband Dana and her grown children. Her daughter Emma, 29, is a US Air Force Captain and a Medical ICU nurse now preparing for her second deployment to the Middle East. Son Charles, 26, recently graduated from Chico State University with a degree in criminal justice and is seeking a job in law enforcement.
And at some point, Rhonda plans to sit back and reflect on her long and fruitful career while savoring Sonoma County wines.
Like many who appreciate wine, Rhonda is intrigued by the sensory elegance of what wine grapes become when entrusted to the hands of a masterful winemaker. “I appreciate the growers who provide wineries with the best fruit possible by making critical farming decisions driven by experience, knowledge and research based information.”
“Sonoma County has an ideal climate for growing wine grapes, but it is up to growers to establish then farm a vineyard with a balanced crop load, adequate soil moisture and canopies that maximize desired fruit composition. All that while managing pests, diseases and labor shortages.
I feel honored to have been able to work with
the people who are in this industry.”
Written by Tim Tesconi


- Author: Karen Giovannini
We are pleased to share our 2019 Annual Report available in two formats! We have our print version and are excited to present our story map version!
Special thanks to Michelle Nozzari for putting together the story map version and Deborah Curle for the print version.

- Author: Pamela Kan-Rice
Vice President Glenda Humiston introduced alumni regent-designate Debby Stegura to UC Cooperative Extension staff and their community partners and clientele in Sonoma County on Nov. 15.
After visiting Beretta Dairy, Bayer Farm Park and Gardens, Sheppard Elementary and Stuhlmuller Vineyards, Regent Stegura tweeted:
“Blown away by @ucanr tour of @UCCESonoma work—Beretta Dairy, @UCMasterGarden, @Stuhlmullerwine, @California4H. Saw #kincaidfire reach, how to prepare better for future fires. @ucanr work benefits all of CA. Thank you!”
The retired business litigator and UC Davis alumna was joined on the tour by Anne Shaw, secretary and chief of staff to the regents, and Michael Bedard, UC state government relations legislative director.
Stephanie Larson, UCCE director for Sonoma County, led the tour, which first visited Beretta Dairy.
“It's so nice to have a dairy advisor,” Sonoma County dairy farmer Doug Beretta said, crediting Randi Black, UC Cooperative Extension dairy advisor, with providing the technical assistance he needed to apply for a grant to reduce methane emissions.
Black, who joined UC ANR in 2017, helped four local dairies obtain grants totaling $2.5 million and said the projects propose to reduce emissions by 9,327 metric tons of CO2 equivalent over the next 5 years, which is comparable to removing 2,028 passenger vehicles from the road for a year.
Beretta talked about the work he has done at the dairy, based on UC research, to improve water quality. David Lewis, UCCE director for Marin and Napa counties, noted that similar manure management and water-quality work is being implemented by UCCE clientele in his counties.
Discussing the hardships created by low milk prices in the dairy industry, Beretta said he appreciated UCCE's agricultural ombudsman Karen Giovannini guiding producers who want to sell value-added products through the permitting process.
From the dairy, Stegura and the group met with Mimi Enright, UC Master Gardener Program manager for Sonoma County, UC Master Gardener volunteers and Julia Van Soelen Kim, North Bay food systems advisor at Bayer Farm Park and Gardens.
Collaborating with Bayer Farm, the Master Gardeners have been expanding outreach to Spanish-speaking members of the community. In addition to all of the traditional Master Gardener outreach, the Master Gardeners in Sonoma County have been actively promoting firewise landscaping to help Sonoma County residents better prepare for wildfires. Using UC ANR materials is critical, Enright said, to assure people the recommendations are based on scientific research.
After the wildfires in 2017, Van Soelen Kim and Enright launched a citizen science project with community partners to assess produce safety. Within days of the fire, volunteers collected 200 samples of leafy greens from school, backyard and community gardens. With funding from UC ANR and the Bay Area Air Quality Management District, they expanded testing to soil and partnered with UC Davis researchers to test eggs laid by backyard poultry, and published guidance for produce safety after urban wildfire.
After the Kincade Fire, when growers and gardeners asked if produce grown outdoors was safe to eat, Enright said UCCE Sonoma County could tell them, based on local research, it was safe to eat if consumers removed outer leaves and washed the produce and that the health benefits of eating fresh produce outweigh any trace contamination.
UCCE has been leading a coalition of community partners and government organizations to educate the community on reducing food waste and increasing food recovery. When PG&E announces public safety power shutoffs, they promote composting food that can't be eaten so it doesn't end up in a landfill.
“This kind of service in communities is not as well-known about UC as the campuses,” Humiston commented to the regent.
Across the street from Bayer Farm, Diego Mariscal, 4-H program assistant, has been collaborating with Sheppard Elementary School. It is one of several schools in the county providing 4-H afterschool clubs and other 4-H programs designed to nurture the next generation of Latino leaders. Last spring, Mariscal worked with families to build a 4-H soccer league for elementary school children. Parents, college and high school students were trained by 4-H to teach children teamwork, soccer skills and healthy eating habits. More than 200 new underserved youth participated in 4-H programs in Sonoma County during the 2018-2019 year.
A few of the soccer players, proudly wearing their green 4-H soccer uniforms, told the group what they liked about 4-H. 4-H All Star Corrianna E., who participates in the 4-H teen program, shared her experience in 4-H and expressed gratitude to the program for helping her overcome her shyness to become a strong public speaker. Corrianna's mother, Naomi Edwards, also shared her experience as 4-H Council President for Sonoma County.
“You want to know what's a good cultural practice? Rhonda Smith has answers backed up by hard science,” Gorman said of the UCCE viticulture advisor.
When new landowners ask Gorman for advice, he refers them to Steven Swain, UCCE environmental horticulture advisor, who advises small parcel land managers in Sonoma County on managing the land for fire and wildlife. “Without UCCE, where would they turn?” Gorman asked, adding that people from private companies may have recommendations that may not be in best interest of the land.
Larson introduced new UC IPM advisor Cindy Kron, who succeeds recent retiree Lucia Varela. Kron is launching an IR-4 project to study pesticides for olives, which isn't a big enough market to interest private investment in research. She's also monitoring pears for brown marmorated stink bug because early detection is key to controlling the pest. Spotted lanternfly isn't in California yet, but grapes are among its favorite hosts so Kron is working with UC Master Gardener volunteers and other community members to watch for the exotic pest.
The Kincade Fire destroyed fences and scorched the rangeland at Stuhlmuller Vineyards, forcing Gorman to sell the cattle. He showed the group where the fire failed to advance at the fire break created by the lush vineyards. As a result of the Kincade Fire, Gorman wasn't able to sell his petite verdot, chardonnay and cabernet grapes to wineries. To prove to the insurance company that smoke damaged the crop, his crew picked 30 tons of grapes for testing.
During and after the devastating fires in the North Bay, Larson, who is also a UCCE livestock and range management advisor, assisted livestock owners to gain access to their burned properties; this ensured their animals got food and water. She also organized resource meetings for landowners affected by fires, helping them apply for funding from government agencies and insurance companies for animal, forage and facility losses.
Larson also said her new grazing database Match.Graze has been well-received by ranchers and landowners in Sonoma and Marin counties who want to use grazing to reduce fire fuels. Land managers and grazers can sign up at ucanr.edu/matchgraze to hire sheep, goats, cattle and horses to manage fire fuels.
The regent tours in Sonoma Country and Fresno County were coordinated by Anne Megaro, government and community relations director. She is planning future tours for regents at UC South Coast Research and Extension Center and other locations in the spring.
- Author: Rhonda J Smith
- Contributor: Akif Eskalen
For the first time many growers are facing the dilemma of what to do with fruit that will not be sold. Although wine inventories have been slowly building over the past few years, 2019 is the first year in which a number of growers are feeling the effects of excess supply due to the large 2018 crop.
Given that yields thus far for most growers have been “average” or better and there is significant unsold inventory of bulk wines, custom crushing uncontracted grapes in 2019 may not be a viable option. Hopefully there will be buyers as the harvest continues but in this market, the prices offered are likely to be less than the cost of production.
Allowing unsold fruit to remain on the vines may seem unthinkable yet with no income from those blocks, it makes sense. This means not dropping clusters by hand and not running a harvester in the vineyard to get the berries off.
From the perspective of a plant pathologist:
clusters that decompose over the winter - either on the vine or on the ground -
are not likely to have a noticeable effect on fungal disease pressure the following year given common vineyard floor management practices.
All common grapevine fungal pathogens exist inside vineyards. For example, fallen petioles, rachises that remain on the vine after mechanical harvest, pruning debris and woody tendrils that cling to trellis wires all support the growth of fungi. These fungi act as sources of inoculum that can infect wounds caused by pruning and suckering, and infect berries at bloom and other green tissue.
The fungi that colonize decaying berries include the same fungi seen growing on damaged berries before harvest including Botrytis cinerea and Cladosporium and Aspergillus species which are associated with Botrytis bunch rot, Cladosporium rot and sour rot respectively. Fungi can infect then colonize the ripening berries when spores enter through the slightest opening in the berry cuticle caused by sunburn or the presence of diffuse, unseen powdery mildew. Berries are an overwintering structures for these fungi and others.
Botrytis cinerea spores are ubiquitous given the fungus can survive on dead tissue as well as infect living tissue. It grows on dead calyptras (flower caps) and stamens after bloom and will infect a young berry through the wounds left when the cap is shed. In various studies, Botrytis sporulation in the lab occurred on petioles and rachises collected on the ground and remnants of rachises collected from canes after pruning.
- Eliminating pruning debris will remove the inoculum formed on decomposing clusters and pieces of canes prior to bud break. Vineyard access to alternate rows is required to incorporate last year's wood and cluster remnants while maintaining resident vegetation or a sown cover crop in the non-tilled rows.
All common grapevine fungal pathogens exist inside vineyards and the relative importance of allowing unsold fruit to remain on the vines should be put into perspective of other vine tissues that are also decomposing. Clusters that remain in the vineyard are not likely to have a noticeable effect on disease the following year if common vineyard floor management practices are followed.
Acknowledgement: Valuable input provided by Dr. Akif Eskalen, Cooperative Extension Plant Pathologist, UC Davis.
- Author: Karen Giovannini
We are pleased to welcome Cindy Kron, PhD as our Area Wide IPM Advisor for Sonoma, Napa, Mendocino and Lake counties.
Cindy has conducted research on a variety of insects including:
- two-year vineyard study on the population dynamics of Virginia creeper leafhopper, western grape leafhopper, and variegated leafhopper
- dissertation research projects investigating the biology and behavior of the three-cornered alfalfa hopper and their relationship with vineyards
- the effects of temperature on the developmental rate of the invasive European grapevine moth
- rearing brown marmorated stink bugs for USDA fumigation studies
Between UC Davis and UCCE, Cindy continued her study of the three-cornered alfalfa hopper as a Research Entomologist for USDA in their Crop Disease, Pests, and Genetics research unit. She tested additional cover crop species as feeding and reproductive hosts of the three-cornered alfalfa hopper in addition to testing commercially available biocontrol agents against the different life stages of the treehopper. She collaborated with a UC Davis colleague to create a degree day model that predicts the ideal timing to implement cultural control measures with the greatest impact on treehopper populations.
“My experiences have motivated me to help growers, stakeholders, and the industry solve agricultural pest management problems through applied research by identifying IPM strategies and tactics that are economically feasible and implementable while having the lowest environmental impact.”
When she is not working with insects, Cindy loves wine tasting, gardening, cooking and canning. She's come to the right place for ALL of that.
Welcome to Wine Country, Dr. Cindy Kron!