Division of Agriculture and Natural Resources
Division of Agriculture and Natural Resources
Division of Agriculture and Natural Resources
University of California
Division of Agriculture and Natural Resources

Roger A Duncan

Photo of Roger A Duncan
Pomology & Viticulture Farm Advisor and County Director
University of California Cooperative Extension, Suite A. Corner of Service and Crows Landing
3800 Cornucopia Way
Suite A
Modesto, CA 95358
(209) 525-6800
raduncan@ucanr.edu Create VCard

Biography

I serve as the Director and pomology and viticulture advisor for UC Cooperative Extension in Stanislaus County.  I conduct research and education programs directed towards growers, pest control advisors, consultants and other industries related to the approximately 200,000 acres of almonds, peaches, and wine grapes in Stanislaus County.  I also serve as a source of information for growers of other miscellaneous tree fruit species. Although Stanislaus County is a major agricultural area, my large clientele base (2125 farms) is comprised mostly of small acreage growers, where approximately 75% of the farms are 40 acres or fewer. My research efforts include evaluation of rootstocks, varieties, orchard design and pruning systems, alternatives to pre-plant fumigation, labor reduction in peaches, tree fertility and integrated pest management.

Education

M.S. Plant Science / Plant Pathology, C.S.U. Fresno. 1990
B.S. Plant Science / Plant Pathology, University of California, Davis. 1987

Specialty

Almonds, Peaches, Grapes, misc. tree fruit

Areas of Expertise (click to see all ANR academics with this expertise)

Bibliography

Peer Reviewed

  • Duncan, R.; Adaskaveg, J.; Hasey, J. (2011). Diseases. UC IPM Pest Management Guidelines: Peach. UC ANR. Pub #3454
  • Duncan, R.; Day, K.; Hasey, J.; Roncoroni, J. (2011). Nematodes. UC IPM Pest Management Guidelines: Peach. UC ANR. Pub #3454
  • Holtz, B.; Duncan, R.; Verdegaal, P.; Klonsky, K. (2011). Sample Costs to Develop an Orchard and Produce Flood Irrigated Almonds: San Joaquin Valley North.
  • Holtz, B.; Duncan, R.; Verdegaal, P.; Klonsky, K. (2011). Sample Costs to Develop an Orchard and Produce Microsprinkler Irrigated Almonds: San Joaquin Valley North.
  • Hasey, J.; Norton, M.; Duncan, R.; DeMura, R. (2011). Sample Costs to Establish and Produce Processing Peaches in the Sacramento and San Joaquin Valleys: Extra Early Harvested Varieties.
  • Hasey, J.; Norton, M.; Duncan, R.; DeMura, R. (2011). Sample Costs to Establish and Produce Processing Peaches in the Sacramento and San Joaquin Valleys: Late Harvested Varieties.

Non-Peer Reviewed

  • Curtis, R.; Gradziel, T.; Connell, J.; Lampinen, B.; Ryan, B.; Duncan, R. (2011). Almond checklist: disease and insect susceptibility, kernel quality and â??fitâ?? for your farming operation and style. Western Farm Press.
  • Gradziel, T.; Curtis, R.; Connell, J.; Ryan, B. (2011). Almond checklist: disease and insect susceptibility, kernel quality and “fit” for your farming operation and style. Western Farm Press.
  • Duncan, R.; Northcutt, G. (2011). Despite challenge by blossom blast, Stanislaus County almond trees set an average or better crop. Tree Nut Farm Press electronic newsletter. May 2011
  • Norton, M.; Duncan, R. (2011). Field Performance of Sixteen Rootstocks in an Unfumigated, Sandy Loam, Replant Location. County Publication.
  • Duncan, R. (2011). Hull samples for boron analysis. Almond Doctor weekly blog. Merced County,
  • Duncan, R. (2011). Hull sampling at harvest to determine boron deficiency. Tree and Vine Newsletter. Merced County University of California Cooperative Extension. September 2011
  • Haseyy, J.; Adaskaveg, J.E.; Duncan, R. (2011). Management of Peach Leaf Curl - New Approaches for an Ever Present Disease. The Scoop on Fruits and Nuts in Stanislaus County. 15: 3.
  • Duncan, R. (2011). New Options for Almond Rootstocks. County publication.
  • Duncan, R. (2011). New Peach Blossom Thinning Machine Improves Fruit Quality and Yield While Reducing Hand Labor Needs. Stanislaus Farm Bureau Newsletter. February 2011
  • Norton, M.; Duncan, R. (2011). Review of String Blossom Thinner Trials in Stanislaus County. County Publication.
  • Gradziel, T.; Curtis, R.; Connell, J.; Ryan, B. (2011). Selecting almond varieties – Bloom, pollination and harvest considerations. Western Farm Press.
  • Curtis, R.; Gradziel, T.; Connell, J.; Lampinen, B.; Ryan, B.; Duncan, R. (2011). Selecting almond varieties â?? Bloom, pollination and harvest considerations. Western Farm Press.
  • Duncan, R.; Anderson, K. (2011). Stanislaus Area Orchard and Vineyard Service Directory.

California Agriculture Article Contributions

ANR Workgroup Associations

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