Richard T. Nagaoka             
Viticultural Consultant
St. Helena, CA, in the heart of the Napa Valley

Goal: To utilize scientific knowledge and production experience to improve wine grape quality.


1983-present:  Viticultural Consultant, St. Helena, California

Consultant to vintners and growers with emphasis on field research, feasibility analysis; vineyard development, studies/block design/trellis, diagnosis/treatment, rootstock recommendations; wine grape brokerage; technical studies; expert witness.

1979-83:  Technical Director, Napa Valley Vineyard Company, Rutherford, California

Responsible for crop protection and cultural programs for 2,300 acres Napa and Sonoma Valley Vineyards managed for ten clients. Monitored and scheduled delivery of more than 26,000 tons of grapes to 22 wineries.  Designed and conducted research projects resulting in publication of scientific papers. Conducted vineyard feasibility studies and maintained technical relationship with clients and wineries.

1969-79:  Senior Viticulturalist, E & J Gallo Winery Ranch, Livingston, California

Directed insect, disease and nutritional diagnosis, treatment and control on 8,000 acres of vineyard and crops in Livingston, Modesto, Hopeton and Fresno. Managed nursery propagation and safety training procedures.  Researched cultural and environmental methods to improve wine quality and managed vineyard experimental wine projects.

1966-69:  Assistant Viticulturist and Laboratory Director, Christian Brothers Winery, Napa, California

As Assistant Viticulturalist, completed experiments in pruning, fertilization, irrigation, climate effects, trellising, and experimental wine production.  As Laboratory Director, conducted wine and must analysis and quality control. 

1965-66:  Wine Chemist, Bisceglia Brothers Wine Co., Madera, California

In charge of wine, must, and high-proof analysis, quality control, blending, cellar inventory, and records.


1961-65:  University of California, Davis, California

Bachelor of Science degree, Viticulture, June 1965.  Followed plant science curriculum with emphasis in plant physiology, soils, chemistry, and agricultural economics. Advanced undergraduate studies in indexing nematode tolerant rootstocks. Wine institute scholarship recipient.

Professional Affiliations:

American Society for Enology and Viticulture, Director 1980-82, 1982-84; professional member since 1966

Napa Valley Vineyard Technical Group, President 1986; member since 1979

Napa Valley Wine Technical Group, Secretary/Treasurer 1968

Napa Valley Grape Growers Association

Pierce’s Disease Task Force

California Weed Science Society

Northern California Enology Club


American Society of Wine Educators, Industry Instructor

University of California Extension Course Coordinator, Instructor

Napa Valley Wine Library Association, Instructor

Wine Grape Broker, License GA337000

California Pest Control Advisor, License 3228

California Community College Teaching Credential

American Arbitration Association, Panelist

Expert Witness


Cornelius S. Ough, Richard T. Nagaoka.  Yield, Compositional and Wine Tasting Differences Between Three Thinning Levels on Cabernet SauvignonAmerican Journal for Enology and Viticulture, Vol. 35, No. 1, p. 30-34, 1983.

W. E. Wildman, R. T. Nagaoka, and L. A. Lider.   Monitoring Spread of Grape Phylloxera by Color Infrared Photography and Ground InvestigationAmerican Journal for Viticulture and Enology, Vol. 34, No. 2, p. 83-94, 1983.

Richard T. Nagaoka.  The Crop Response of Gewurztraminer to Cutworm Feeding Injury by Bud Position.  Presented June 1986,  American Society for Enology and Viticulture Annual Meeting.

Richard T. Nagaoka, Cornelius S. Ough.  The Influence of Devigorating Rootstock on the Vine Performance and Wine Quality of Cabernet Sauvignon. American Vineyard Foundation. Funded l987-1991, and presented June 1992, American Society for Enology and Viticulture Annual Meeting.

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1999 by The Grape Doctor, Richard T. Nagaoka, Viticultural Consultant
1171 Edwards Street, St. Helena, CA, 94574-1208, USA -- --