Sharon M. Douglas

Portrait of Sharon M. Douglas

Department of Plant Pathology and Ecology

The Connecticut Agricultural Experiment Station
123 Huntington Street
P.O. Box 1106
New Haven, CT 06504-1106
Fax: (203) 974-8502


Dr. Douglas has expertise in detection, mitigation, and management of plant health problems. She also has expertise in physiological and genetic bases of host-pathogen interactions and the biology and epidemiology of phytoplasma-associated diseases, particularly X-disease of stone fruits.


A.B. Colgate University (1976); Biology

M.S. University of New Hampshire (1978); Botany and Plant Pathology

Ph.D. The Pennsylvania State University (1982); Plant Pathology

Station career:

Assistant Scientist 1982-1993

Associate Scientist 1993-2000

Scientist 2000-2007

Chief Scientist, Head, Department of Plant Pathology and Ecology 2007-2015

Emeritus Scientist 2015-present

Service activities:

The Department of Plant Pathology and Ecology’s service efforts focus on the diagnosis of plant health problems for all Connecticut residents, including homeowners, plant care professionals (e.g., arborists, landscapers, garden centers), and commercial growers (e.g., greenhouse, vegetable, nursery, orchard, and vineyard crops). Department scientists work closely with stakeholders to develop disease management programs that require minimal use of pesticides and are compatible with the environment. The department has an active outreach program, which offers numerous fact sheets, web-based information, workshops, town meetings, and presentations for green industry professionals, garden and horticultural clubs, and students.

Current responsibilities and research:

Oversees scientists in the Department who conduct research on the biology and ecology of plant pathogens and interactions between plants, pathogens, and the environment. Department research includes original, basic investigations involving the ecology and genetics of plant pathogens, new and emerging diseases, and models for predicting the spread of plant pathogens. The mission of the department is to manage plant health problems using innovative methods to protect the environment, ensure a safe food supply, and maintain a healthy landscape for Connecticut. Additionally, oversees the Plant Disease Information Office, a full-service diagnostic office that helps identify plant health problems for stakeholders. Co-directs the Molecular Plant Diagnostics Laboratory created to develop rapid, accurate methods to detect new or re-emerging plant pathogens. Maintains an active outreach program through authorship of fact sheets and presentations for growers, arborists, horticultural clubs, special interest groups, and students. Cooperates with CT state regulatory personnel and USDA-APHIS-PPQ for detection and diagnosis of select agents and plant pathogens of national regulatory concern and oversees the CT seed testing program, as the official seed testing laboratory for Connecticut.

Current research is focused on mitigation strategies for boxwood blight caused by the fungus Calonectria pseudonaviculata. This new emerging, destructive disease of boxwood was first identified in October 2011 in North America (CT and NC) and has resulted in losses estimated at $5 million in CT alone.

Past research:

Previous research interests focused on understanding the physiological and genetic bases of host-pathogen interactions. These included investigating the relationship between vascular alterations and disease symptom development in Verticillium wilt of chrysanthemum and the physiological and physical basis of adult plant resistance of oats to Erysiphe graminis f. sp. avenae. Upon joining the Station, her research project focused on understanding the biology and epidemiology of diseases associated with phytoplasmas, primarily X-disease of stone fruits.

Selected publications available from author,, or on-line on this website:

  • Davis, R. E., Y. Zhao, E. L. Dally, I.-M. Lee, R. Jomantiene, and S. M. Douglas. 2013. ‘Candidatus Phytoplasma pruni', a novel taxon associated with X-disease of stone fruits, Prunus spp.: multilocus characterization based on 16S rRNA, secY, and ribosomal protein genes. International Journal of Systematic and Evolutionary Microbiology 63:766-776.
  • Douglas, S. M. and M. K. Inman. 2013. Seed germination and purity analysis 2013. CAES Technical Bulletin #9. 15 p. (PDF)
  • Douglas, S. M. 2012. Some key diseases of conifers. Tree Care Industry Magazine. Volume XXIII (10):22-27.
  • Douglas, S. M. 2012. Guidelines for reporting and managing boxwood blight in Connecticut landscapes (Version 2.0). CAES Fact Sheet (PDF)
  • Ivors, K. L., L. W. Lacey, D. C. Milks, S. M. Douglas, M. K. Inman, R. E. Marra, and J. A. LaMondia. 2012. First report of boxwood blight, caused by Cylindrocladium pseudonaviculatum in the US. Plant Disease 96 (7):1070.
  • LaMondia, J. A., D. W. Li, R. E. Marra, and S. M. Douglas. 2012. First report of Cylindrocladium pseudonaviculatum causing leaf spot of Pachysandra terminalis. Plant Disease 96 (7):1069.
  • Douglas, S. M. 2011. Boxwood blight—A new disease for Connecticut and the U.S. CAES Fact Sheet (PDF)
  • Douglas, S. M. 2011. Boxwood blight. CAES Disease Alert (PDF)
  • Douglas S. M. 2011. Disease diagnosis and eco-friendly management—Part 1. Tree Care Industry Magazine. Vol XXII, Number 6 (June): 22-25.
  • Douglas, S. M. 2011. Fifty years of Connecticut Christmas trees: A plant pathologist’s perspective. Christmas Trees (Fall 2011) 38 (4): 8-10.
  • Douglas, S. M. 2008. Plant Health Problems- Intro and Historical Impact of Plant Health Problems. CAES Fact Sheet (PDF)
  • Douglas, S. M. 2007. Disease Management Guide for Connecticut Arborists 2007-2008. Connecticut Tree Protective Association, 420p.
  • Douglas, S. M. 2007. Healthy roots lead to healthy plants. GMPRO Magazine, January 2007 Issue, p. 90-96.
  • Douglas, S. M. 2005. Update on Sudden Oak Death in Connecticut. Connecticut Woodlands Magazine. Spring 2005 issue.

Additional Outreach Publications:

  • Douglas, S. M. 2011. Coloring and Activity Book for Kids III (2011) (PDF)
  • Douglas, S. M. 2008. Coloring and Activity Book for Kids II (2008) (PDF)