Gary W. Moorman, Ph.D.

Extension Program

The primary objective of the Ornamentals Plant Pathology Extension program is to teach commercial nurserymen and greenhouse operators, landscape maintenance personnel, pesticide applicators, and Extension educators how to detect, identify, and manage plant diseases. This entails lectures, workshops, tours, internet conferences, telephone and internet consultations, and on-site visits to provide information on the biology of plant pathogens and their interactions with the plant and the environment.
In addition to being able to diagnose diseases, an important goal of the program is to teach clientele how to trace where disease began and then deal with those harbors in ways that sustainably prevent future outbreaks.
This work is done statewide and is coordinated others who participate on the College of Agricultural Sciences Horticulture-Green Industry Natural Work Group.

Teaching Program

Gary Moorman currently teaches PPATH 300, Diseases of Horticultural Crops. This online course is composed of narrated PowerPoints, numerous videos, virtual lab exercises, and richly illustrated text-based lessons. Assignments include finding, photographing and diagnosing several different types of diseases of horticultural crops. Students have the opportunity to explore a topic of their choosing related to horticultural crop diseases by writing a special interest paper to be shared with the entire class.

Research Program

Integrated management of zoosporic pathogens and irrigation water quality for a sustainable green industry, is a $2.7M project funded by the USDA Specialty Crops Research Initiative for 2010-2015. The research is in collaboration with C. Hong, Ping Kong, Kevin K. Boyle, Darrell Bosch, Boris Vinatzer, and James Pease (Virginia Tech), John Lea-Cox (University of Maryland), Warren Copes (USDA, Poplarville, MS) Gladis Zinati (Rutgers University) and Edward Weiss (Christopher Newport University).  The mission of this work is to enable nurserymen and greenhouse operators to recycle irrigation water without recycling plant pathogens. Through the integration of research and extension activities that take system-based, trans-disciplinary approaches, our goal is to better understand the biology of species of Pythium and Phytophthora that pose serious threats to the production of ornamental plants and can be dispersed in production systems through contaminated irrigation water. Moorman’s lab is working on the detection and identification of species of Pythium in commercial greenhouses. Of particular interest is the characterization of bacterial communities associated with Pythium and irrigation water that may inhibit the life cycle of Pythium and/or the disease cycle of Pythium diseases.

Elm yellows in the Centre Region is a project initiated in response to a severe outbreak of that phytoplasma associated disease. The elm yellows pathogen, vectored by leafhoppers, threatens the continued health of the over 200 mature American elms on the Penn State University Park campus. In collaboration with Greg Hoover and Cristina Rosa (Entomology Department) and Jeffrey Dice and Kris Edson (Office of Physical Plant) the epidemiology and management of elm yellows and its vectors is being researched. Project website: https://secure.hosting.vt.edu/www.irrigation-pathogens.ppws.vt.edu/

Recent Publications

Lee, S. H., Garzón, C. D., and Moorman, G. W. 2010. Genetic structure and distribution of Pythium aphanidermatum populations in Pennsylvania greenhouses based on analysis of AFLP and SSR markers. Mycologia 102-774-784.

Herath, P., G. A. Hoover, E. Angelini, and G. W. Moorman. 2010. Detection of elm yellows phytoplasma in elms and insects using real-time PCR. Plant Disease 94:1355-1360.

Gleason, M. L., Daughtrey, M. L., Chase, A. R., Moorman, G. W., and Mueller, D. S. 2009. Diseases of herbaceous perennials. APS Press. St. Paul, MN. 281 pp.

Kong, P., Moorman, G. W., Lea-Cox, J. D., Ross, D. S., Richardson, P. A., and Hong, C. 2009. Zoosporic tolerance to pH stress and its implications for Phytophthora species in aquatic ecosystems. Applied and Environmental Microbiology 75:4307-4314.

Hong, C., Lea-Cox, J. D., Ross, D. S., Moorman, G. W., Richardson, P. A., Ghimire, S. R., and Kong, P. 2009. Containment basin water quality fluctuation and implications for crop health management. Irrigation Science. Published online 18 June 2009. Springer-Verlag.

Ghimire, S. R. , Richardson, P. A. , Moorman, G. W. , Lea-Cox, J. D. , Ross, D. S. , Hong, C. X. 2009. An in situ baiting bioassay for detecting Phytophthora species in irrigation runoff containment basins. Plant Pathology 58:577-583.

Lee, S. H. and Moorman, G. W. 2008. Identification and characterization of simple sequence repeat markers for Pythium aphanidermatum, P. cryptoirregulare, and P. irregulare and the potential use in Pythium population genetics. Current Genetics 55:81-93. 

Moorman, G. W. and Gwinn, K. D. 2008. Cultural control of plant diseases. In, Plant Pathology Concepts and Laboratory Exercises. R. N. Trigiano, M. T. Windham, and A. S. Windham, eds. CRC Press, Boca Raton, FL. Chapter 35, Pp. 405-414.

Hong, C. X., Gallegly, M., Richardson, P. Kong, P., and Moorman, G. W. 2008. Phytophthora irrigata, a new species isolated from irrigation reservoirs and rivers in eastern United States of America. FEMS Microbiology Letters 285:203-211.

Hu, J. H., Hong, C. X., Stromberg, E. L., and Moorman, G. W.  2008.  Mefenoxam sensitivity and fitness analysis of Phytophthora nicotianae isolates from Virginia nurseries.  Plant Pathology 57:728-736.

Hu, Jiahuai, Hong, C. X, Stromberg, E. L. and Moorman, G. W. 2007. Effects of propamocarb hydrochloride on mycelial growth, sporulation, and infection by Phytophthora nicotianae isolates from Virginia nurseries. Plant Disease 91:414-420.

Garzón, C. D., Yánez, J. M., and Moorman, G. W. 2007. Pythium cryptoirregulare, a new species within the P. irregulare complex. Mycologia 99:291-301.

Moorman, G. W., and Gwinn, K. D. 2007. Cultural Control of Plant Diseases. Pages 405-415 in: Plant Pathology Concepts and Laboratory Exercises, R. N. Trigiano, M. T. Windham and A. S. Windham, eds. CRC Press, Boca Raton, FL.

Moorman, G. W. 2006. Disease Management. In, Cutting Propagation. J. M. Dole and J. L. Gibson, eds. Ball Publishing, Batavia, IL. pp. 101-114.

Hong, C. X. and Moorman, G. W. 2005. Plant pathogens in irrigation water: Challenges and opportunities. Critical Reviews in Plant Science: 24:1889-1908.

Garzón, C. D., Geiser, D. M., and Moorman, G. W. 2005. Amplified fragment length polymorphism analysis and internal transcribed spacer and cox II sequences reveal a species boundary within Pythium irregulare. Phytopathology 95:1489-1498.

Garzón, C. D., Geiser, D. M., and Moorman, G. W. 2005. Diagnosis and population analysis of Pythium species using AFLP fingerprinting. Plant Disease 89:81-89.

Kong, P., Richardson, P. A., Moorman, G. W., and Hong, C. 2004. Single-strand conformational polymorphism analysis of the ribosomal internal transcribed spacer 1 for rapid species identification within the genus Pythium. FEMS Microbiology Letters 240:229-236.

Moorman, G. W., Hong, C. X., and Richardson, P. A. 2004. First report of Phytophthora cinnamomi on Ilex glabra in Virginia. Plant Disease 88:1283.

Moorman, G. W. and Kim, S. H. 2004. Species of Pythium from greenhouses in Pennsylvania exhibit resistance to propamocarb and mefenoxam. Plant Disease 88:630-632.

Kim, S. H., Olson, T. N., Schaad, N. W., and Moorman, G. W. 2003. Ralstonia solanacearum race 3, biovar 2, the causal agent of brown rot of potato, identified in geraniums in Pennsylvania, Delaware, and Connecticut . Plant Disease 87:450.

Moorman, G. W. 2003. Cultural control of plant diseases. In, Plant Pathology Concepts and Laboratory Exercises. R. N. Trigiano, M. T. Windham, and A. S. Windham, eds. CRC Press, Boca Raton, FL. Chapter 32, Pp. 313-318.

Moorman, G. W., Kang, S., Geiser, D. M., and Kim, S. H. 2002. Identification and characterization of Pythium species associated with greenhouse floral crops in Pennsylvania . Plant Disease 86:1227-1231.

Moorman, G. W., Kang, S., Geiser, D. M., and Kim, S. H. 2002. Identification and characterization of Pythium species associated with greenhouse floral crops in Pennsylvania . Plant Disease 86:1227-1231.