Plant Pathology Graduate Program

Georgios Vidalakis

Georgios Vidalakis
Office: 951-827-3763
Department of Plant Pathology, Riverside, CA 92521
Office Hours: , not specified - not specified
Email: vidalg@ucr.edu

Georgios Vidalakis

Professor & UC Extension Specialist in Plant Pathology
Director, Citrus Clonal Protection Program (CCPP)
Graft-transmissible Diseases of Citrus

Ph.D. Plant Pathology - Citrus Virology, 2004. University of California, Riverside
B.Sc. Agricultural Science - Plant Protection & Environment, 1998. Agricultural University of Athens, Greece

Biography & Research Interests

My research is on viral and potential microbial diseases of citrus in California. In my lab, we study the etiology of putative viral diseases, as well as the ecology and molecular biology of citrus-infecting viruses in California focusing in . Citrus viroids present an excellent system for molecular evolutionary studies. In my laboratory we investigate the intra-population structures of the self-replicating viroid RNA molecule in combination with the molecular and biological properties of the progeny viroids in an effort to reveal evolutionary patterns that effect pathogenicity, infectivity and other features of the smallest known plant pathogen. My responsibilities also include being the director of the Citrus Clonal Protection Program (CCPP). This internationally recognized program provides researchers and growers with stocks of stable, disease-tested citrus fruit and rootstock varieties. Over 200 important varieties are maintained by the program which are routinely tested for diseases and evaluated horticulturally. In addition, through its disease testing and disease elimination capabilities, the CCPP provides a safe mechanism for importing citrus varieties from other countries. The CCPP thereby serves as a valuable and prestigious resource for scientists at UCR and throughout the world that are interested in variety improvement.

Citrus Clonal Protection Program (CCPP)



Special Dean's Fellowship Award, 2000-2004. UC Riverside


Secretary, International Organization of Citrus Virologists (IOCV)
Chair, National Citrus Clean Plant Network 


  1. Vidalakis, G., Garnsey, S. M., Bash, J. A., Greer, G. D., and Gumpf, D. J. 2004. Efficacy of bioindexing for graft-transmissible citrus pathogens in mixed infections. Plant Dis. 88:1328-1334.
  2. J. S. Semancik and G. Vidalakis. 2005. The question of Citrus viroid IV as a Cocadviroid, Archives of Virology 150: 1059-1067.
  3. N. önelge, A. Cinar, J.A. Szychowski, G. Vidalakis and J.S. Semancik. 2005. Citrus viroid II variants associated with ‘Gummy Bark’ disease. European Journal of Plant Pathology 110: 1047-1052.
  4. J. A. Szychowski, G. Vidalakis and J. S. Semancik. 2005. Host directed processing of Citrus exocortis viroid. J Gen Virol 86(2005), 473-477.

More Information

General Campus Information

University of California, Riverside
900 University Ave.
Riverside, CA 92521
Tel: (951) 827-1012

Career OpportunitiesUCR Libraries
Campus StatusDirections to UCR

Contact Information

Graduate Program in Plant Pathology
1140 Batchelor Hall

Tel: (800) 735-0717 or (951) 827-5688
Fax: (951) 827-5517
E-mail: laura.mcgeehan@ucr.edu

Department of Plant Pathology and Microbiology
Boyce Hall 1463

Tel: (951) 827-3598
Fax: (951) 827-4294
E-mail: margarita.flores@ucr.edu