Gary W. Moorman, Ph.D.

Gary W. Moorman, Ph.D.

  • Professor Emeritus


  • B.S., Botany, University of Maine, 1971
  • M.S., Botany, University of Vermont, 1974
  • Ph.D., Plant Pathology, North Carolina State University, 1978

Extension Program

The primary objective of the Ornamentals Plant Pathology Extension program was to teach commercial nurserymen and greenhouse operators, landscape maintenance personnel, pesticide applicators, and Extension educators how to detect, identify, and manage plant diseases. In addition to being able to diagnose diseases, an important goal of the program was to teach clientele how to trace where disease began and then deal with those harbors in ways that prevent future outbreaks.

Teaching Program

Gary Moorman taught PPATH 300, Diseases of Horticultural Crops for many years as a traditional classroom/lab course. He converted it into an online course composed of numerous videos, virtual lab exercises, and richly illustrated text-based lessons.

He also participated in teaching Plant Pathology Concepts, Fundamentals of Phytopathology, Techniques in Nematology, and Plant Disease Diagnosis.

Research Program

Moorman worked on many research projects that contributed to his Extension program. One goal was to better understand the identity and biology of species of Pythium that pose a threat to commercial greenhouse crops with particular emphasis on those species that were thought to be dispersed via contaminated irrigation water.

Other research projects examined fungicide resistance in Botrytis and Pythium, the effect of fertilizer composition and concentration on Pythium root rots in geranium and poinsettia, and the detection and spread of elm yellows in the elm population on the University Park campus.

Selected Publications

  • Choudhary, C. E., Burgos-Garay, M. L., Moorman, G. W. and Hong, C. 2016. Pythium and Phytopythium species in two Pennsylvania greenhouse irrigation tanks. Plant Disease 100:926-932.
  • Hong, C., Moorman, G. W., Wohanka, W., [editors]. Biology, detection, and management of plant pathogens in irrigation water. St. Paul, MN: American Phytopathological Society, 2014.
  • Moorman, G. W., Walker, A-S., and May, S. 2012. First report of fenhexamid-resistant Botrytis cinerea causing gray mold on Heuchera in a North American greenhouse. Plant Disease 96:147.
  • Garzón, C. D., Molineros, J. E., Yánez, J. M., Flores, F. J, Jiménez-Gasco, M. M., and Moorman, G. W. 2011. Sublethal doses of mefenoxam enhance Pythium damping-off of geraniums. Plant Disease 95:1233-1238.
  • 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.
  • 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.
  • 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.

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

  • 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 Dis. 87:450.

  • 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.

  • Sulzinski, M. A., Schlagnhaufer, B., Moorman, G. W., and Romaine, C. P.  1998. PCR-based detection of artificial latent infections of geranium by Xanthomonas campestris pv. pelargonii. Journal of Phytopathology 146:111-114.

  • Vali, R. J., and Moorman, G. W.  1992.  Influence of selected fungicide regimes on frequency of dicarboximide-resistant and dicarboximide-sensitive strains of Botrytis cinerea.  Plant Disease 76:919-924.
  • Moorman, G. W., J. S. Huang, and N. T. Powell.  1980.  Localized influence of Meloidogyne incognita on Fusarium wilt resistance of flue-cured tobacco.  Phytopathology 70:969-970.
  • Moorman, G. W.  1976.  Mitosis in Ancylistes sp. Mycologia 68:902-909.