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About the Advisor Emeritus

James A. Bethke is the Floriculture and Nursery Farm Advisor Emeritus for San Diego and Riverside Counties.

The Floriculture and Nursery Farm Advisor Emeritus conducts applied research, education and outreach programs to improve production and viability of the floriculture and nursery industries in San Diego and Riverside Counties. The Floriculture and Nursery Industry in San Diego County is a one billion dollar industry, and in Riverside County, it is second in crop value at $211 million. The rapid population growth in the San Diego and Riverside areas is reflected in the changes in the floriculture and nursery industry.

Due to rapidly increasing land values and ag/urban interface issues, nursery and flower operations are moving from the coast to inland areas, resulting in changes in growing practices and plants produced. Many growers are new to the industry and require a high level of assistance in managing their growing operations. Environmental issues such as water quality and exotic pests are challenging the viability of the industry.

Additional Information


My program emphasizes the integrated pest management of major pests of floriculture and nursery production. Ornamental producers are challenged with protecting an aesthetic crop that in most cases cannot have any blemish, and sometimes, best management practices can elude them. Some of the most vexing issues in ornamental production at the moment in Southern California are the regulatory restrictions and mandates associated with very serious invasive pests. Research on these invasives lack and in many cases there is almost nothing known about some of these pests. Further, the impact that some of these invasives can have on the movement of an ornamental commodity can be quite severe. Therefore, I collaborate with regulators, growers, and other scientists on advisory committees that set policy based on science.


A.A. 1974. Biology, Fullerton City College

B.S. 1982. Entomology, University of California, Riverside (Honors)

M.S. 1985. Entomology, University of California, Riverside

Professional Experience:

Sept 2007-Present - San Diego and Riverside Counties Floriculture and Nursery Farm Advisor. My duties include research and extension related activities in the area of floriculture and ornamental horticulture. At present, I am addressing the serious impacts on the ornamental industry due to a series of invasive pests.

July 2005- Sept 2007 - Split appointment - Staff Research Associate, Department of Entomology, University of California, Riverside 40%, Floriculture farm Advisor San Diego County 60%. My duties include research and extension in the field of ornamental horticulture.

June 1985- Sept 2007 - Staff Research Associate, Department of Entomology, University of California, Riverside. My duties in Dr Richard Redak's laboratory include supervision of staff members and research on insects that attack ornamentals in nurseries and greenhouses.

Sept. 1981-June 1985 - Graduate Research Assistant for Dr. Michael P. Parrella in the Department of Entomology, University of California, Riverside. The leafpuncturing, ovipositional and feeding behavior of the leafminer, Liriomyza trifolii (Burgess) was investigated on preferred and non-preferred hosts.

March 1980-Sept. 1981 - Laboratory Assistant, Department of Entomology, University of California, Riverside. Under the direction of Dr. Michael P. Parrella, we investigated the biology and control of leafminers attacking ornamentals in nurseries and greenhouses.

Awards and Honors:

Lena and Fay Reynolds Scholarship, Fullerton City College 1980 and 1981.
Jessica Jenkins Scholarship, UCR 1982.
Chancellors Ball Fellowship, UCR 1982.
Graduate Student Council Mini-Grant, UCR 1983
Rakuo Hayashi Orange County Chapter Scholarship Award 1983
Roy M. Nakase Memorial Scholarship Award 1983
Orange County Chapter C. A. N. Scholarship Award 1983
Oda Nursery Award 1983
Gama Sigma Delta Graduating Senior Award 1983.
Myron Winslow scholarship, UCR 1985.
Professional Achievement Award, UCR 1990-91
Incentive and Professional Development Award, UCR, 1996, 1997, 2003, 2005, 2006
Outstanding New Academic, Distinguished Service Award 2011
Outstanding Person of the Year Award 2013, San Diego County Flower and Plant Association
Outstanding Contribution to Agriculture 2013, California Association of Pest Control Advisers
2014 CANERS Research Award: California Association of Nurseries and Garden Centers

Professional Organizations and Memberships:

Entomological Society of America, 1980-Present.
Gama Sigma Delta, 1983-Present.
Pesticide Applicators Professional Association, 1990-Present

Selected Publications:

Bender, G. S., L. M. Bates, J. A. Bethke, E. E. Lewis, G. S. Tanizaki, J. G. Morse and K. E. Godfrey. 2014. Evaluation of Insecticides, Entomopathogenic Nematodes, and Physical Soil Barriers for Control of Diaprepes abbreviatus (Coleoptera: Curculionidae) in Citrus. Jo. Econ. Entomol. (In Press).
Villavicencio, L., J. A. Bethke, B. Vander Mey, B. Dahlki and L. Corkidi. 2014. Curative and Preventive Control of Aceria aloinis (Acari: Eriophyidae) in Southern California. Jo. Econ. Entomol. (In Press). Accepted Aug 25, 2014.
C. L. McKenzi, J. A. Bethke, F. J. Byrne, J. Chamberlin, T. Dennehy, A. Dickey, D. Gilrein, P. Hall, S. Ludwig, R. D. Oetting, L. S. Osborne, L. Schmale, and R. G. Shatters, Jr. 2012. Distribution of Bemisia tabaci (Hemiptera: Aleyrodidae) Biotypes in North America: Containing the Q. J. Econ. Entomol. 105 (3): 753-766.
Cloyd, R. A., J. A. Bethke and R. S. Cowles. 2011. Systemic Insecticides and Their Use in Ornamental Plant Systems. Floriculture and Ornamental Biotechnology. 5(1): 1-9.
Cloyd, R. A. and J. A. Bethke. 2010. Impact of neonicotinoid-based insecticides on natural enemies in protected culture and interiorscapes. Pest Management Science. 67(1): 3-9.
Byrne, F. J., R. D. Oetting, J. A. Bethke, C. Green, and J. Chamberlin. 2010. Understanding the Dynamics of Neonicotinoid Activity in the Management of Bemisia tabaci Whiteflies on Poinsettias. Crop Protection. 29:260-266
Sorensen M. A., J. A. Bethke, and R. A. Redak. 2010. Potential Host Plants of Trirhabda geminata (Coleoptera: Chrysomelidae): Impacts on Survival, Development, and Feeding. Environ. Entomol. 39(1): 159-163.
Bethke, J. A. and R. A. Cloyd. 2009. Pesticide use in ornamentals: what are the benefits? Pest Management Science. 65 (4): 345-350.
Bethke, J. A., F. J. Byrne, G. S. Hodges, C. L. McKenzie and R. G. Shatters, Jr. 2009. First Record of the Q Biotype of the Sweetpotato Whitefly, Bemisia tabaci, in Guatemala. Phytoparasitica. 65(4): 345-350.
Bethke, J. A., M. J. Blua, R. A. Redak, & D. A. Yanega. 2001. Range extension of Pseneo puncatatus and notes on predation of an introduced sharpshooter, Homalodisca coagulata. Pan Pacific Entomology. 77:54-46.
Bethke, J. A., M. J. Blua, & R. A. Redak. 2000. Effect of selected pesticides on Homalodisca coagulata (Homoptera: Cicadellidae) and transmission of oleander leaf scorch in a greenhouse study. J. Econ. Entomol. 94:1031-1036.
Costa, H. S., M. S. Blua, J. A. Bethke, & R. A. Redak. 2000. Transmission of Xylella fastidiosa to oleander by the glassy winged sharpshooter, Homalodisca coagulata. Hortscience. 35(7):1265-1267.
Bethke, J. A., R. A. Redak, and U. K. Schuch. 1998. Melon Aphid Performance on Chrysanthemum as Mediated by Cultivar, and Differential Levels of Fertilization and Irrigation. Entomologia Exper. Appl. 88: 41-47.


Over 300 scientific and technical research presentations have been presented since 1982. In addition, >200 informal presentations have been given to community organizations, churches, camps, schools, etc.