Nancy G. Wenner

Nancy G. Wenner

  • Assistant Research Professor
116 Buckhout Lab (office) (voicemail 814-865-0717)
417 Buckhout Lab (Kuldau lab) (814-865-6986)

University Park, PA 16802

Areas of Expertise

  • Ornamental plant disease diagnosis
  • Conifer diseases
  • Mycology
  • Fungal isolation
  • Microscopy
  • Photographic documentation
  • Chromatography
  • Laboratory safety and management


  • B.S., Horticulture, Penn State
  • M.S., Plant Pathology, Penn State
  • Certified Online Instructor

Areas of Interest

Plant disease diagnosis & control, Mycology, Photography, Microphotography, Horticulture, Entomology, Gardening, Chromatography-HPLC & GC, Microbiology, PCR & DNA sequencing, Laboratory Safety & Management.


PPEM 300 - Diseases of Horticultural Crops  

 3 Credit; web-based course. Offered Fall Semesters through Penn State Ag. Sciences eLearning and World Campus Online Courses. 

PPEM 300 is an introduction to the core concepts of plant pathology, focusing examples on diseases of horticultural crops. This completely web-based course is taught in a series of online modules, richly illustrated with photographs, diagrams, videos, and virtual lab exercises. Students learn to identify and diagnose plant diseases, and to understand the principles of plant pathogen survival and dissemination. Diagnostic exercises require students to find, photograph and submit photos of plant diseases in their own locations. Diagnosis assignments allow students to choose their favorite plant material and receive customized feedback. The course is a great option for individuals at branch campuses or serving internships as well as those who just enjoy studying from home. Students may fulfill their pest management requirement or Gen. Ed. elective online to free "in class" schedules for other required courses. The historical significance of many plant diseases, as well as their current impacts of on economy, trade, and culture, are discussed.

Full Syllabus:

Research Projects

Mycotoxin Project - current

I currently work with Dr. Gretchen Kuldau and assist her students in investigating mycotoxins and other fungal metabolites. Our project “Mycotoxins: Biosecurity and Food Safety," is affectionately nicknamed, “The Cereal Killers," as we evaluate corn, wheat, and sometimes silage or other substrates for mycotoxin development or contamination. The project encompasses a wide range of research, from molecular and chemical bench science to applied chamber, greenhouse, and field trials. We utilize an array of research methods to merge observational studies in mycology and microscopy, with infection and growth studies, which we then may evaluate by chromatography and/or molecular genetic means.  

My projects have included HPLC and GC (ECD) studies to detect mycotoxins in wheat, fungal assays to test new chemicals, and fungal inoculations on various hosts to track infection and the production and fate of mycotoxins in plants and products. 

My project and departmental responsibilities vary widely and can include everything from organism isolation & identification, biological assays, molecular techniques such as PCR and DNA sequencing, to crop production and field trial rating and evaluations. I am often involved with chromatography operation, troubleshooting, and repair, as well as laboratory management, safety, purchasing, and written and photographic documentation for protocols & manuscripts.

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Fungal Studies & Grape Disease Research

In my preceding project, I worked with Dr. Elwin Stewart on the NSF PEET and the PDA Clean (Grape) Vine projects. On the PEET (Partnership for Enhancing Expertise in Taxonomy) project, we worked with several students investigating the phylogenetics of Hypocrealean fungi using DNA extraction, sequencing, and molecular taxonomy. The grape project group investigated the organisms and the circumstances leading to vine decline in grapes, conducted a 3-year vine decline survey evaluating the health of PA & NY vineyards, and isolated and identified the organisms associated with vine decline. This work culminated in the PA Clean Vine program where I learned grape meristem-shoot-tip propagation and developed many cultivars of aseptically propagated 'clean' vines through tissue culture.

Conifer Disease Research & Christmas Trees

In my first project at Penn State, I worked closely with Dr. Bill Merrill on Christmas Trees investigating “Causes, Factors Affecting Development, and Effects of Diseases on Conifer Regeneration." We initiated the annual PSU Christmas Tree Pest Management Short Course and taught other short courses and extension programs throughout the Northeast. Our research focused on conifer foliar needlecasts and needle blights, but included other conifer diseases such as cankers, galls, shoot diebacks, and root rots as well. The research from our work helped growers to diagnose and control conifer disease and insect problems. We were also able to determine that the sporadic browning and dieback of Pinus strobus foliage sometimes reported as Ozone or other abiotic damage in the Northeast and in Acadia National Park was attributable to infection by a needlecast fungus, Canavirgella banfieldii (Lophophacidium dooksii), which is quickly overtaken and masked by secondary organisms. 




Tania Galindo‐Castañeda, Kathleen M. Brown, Gretchen A. Kuldau, Gregory W. Roth, Nancy G. Wenner, Swayamjit Ray, Hannah Schneider, Jonathan P. Lynch. 2019. Root cortical anatomy is associated with differential pathogenic and symbiotic fungal colonization in maize. Plant Cell Environ. 42:2999–3014. 

Gretchen Kuldau, Hunter Swisher, & Nancy Wenner. Exploring the relationship between Morchella americana and tree roots in Pennsylvania. Poster. Mycological Society of America, Athens, Georgia. 16-19 July 2017.

Joseph Firrantello, N.G. Wenner, Paul Kremer, Gretchen Kuldau, Edward Kaiser, William Bahnfleth, & Ross Montgomery. The Use of UVC Germicidal Lamps for Improved Energy Efficiency and Remediation of Microbially Fouled HVAC Cooling Coils. Poster. The 5th Annual SLOAN MoBE (Microbiology of the Built Environment) Conference. 1-2 June 2015.

Guo, L., Wenner, N. & Kuldau, G.A. (2015b). FvSO regulates vegetative hyphal fusion, asexual growth, fumonisin B1 production, and virulence in Fusarium verticillioides. Fungal Biology 119, 1158-1169.

Rahman, A., Nancy G. Wenner, & Wakar Uddin. 2015.  Induced systemic resistance responses in perennial ryegrass against Magnaporthe oryzae elicited by semi-purified surfactin lipopeptides and live cells of Bacillus amyloliquefaciens. Mol Plant Pathol. 2015 Aug; 16(6):546-58. doi: 10.1111/mpp.12209. Epub 2015 Jan 23.

Hallen-Adams, H.E., Nancy Wenner, Gretchen A. Kuldau, and Frances Trail. 2011.  Deoxynivalenol gene expression during wheat kernel colonization by Fusarium graminearum. Phytopathology. Vol. 101, No. 9, 1091-1096.

Stewart, E.L., B.E. Overton, and N.G. Wenner. 2008. Towards a Clean Grapevine Program for the Mid-Atlantic: How To---Detect Petri disease, Tomato Ring Spot Virus, Crown Gall in Grape using Molecular Methods and Initiate a Grape Meristem Tip Culture Program. The Pennsylvania State University, 62 pages.

Morton, L., N.G. Wenner, E.L. Stewart, and B.E. Overton. 2005. Fungi isolated from failing graft unions with necrotic lesions. 4th International Workshop on Grapevine Trunk Diseases. Abstracts. P. 24. Stellenbosch, SA. 20-21 January 2005.

Overton, B. E., E.L. Stewart, X. Qu, N.G. Wenner, B.J. Christ. 2004. Qualitative Real-time PCR SYBR Green detection of Petri disease fungi. Phytopathologia Mediterranea 43: 403-410.

Long, L.A., E.L. Stewart, N.G. Wenner, and B.E. Overton. 2003. Molecular systematics of Phialophora-like Fungi from declining grapevines. (Abstr.) Phytopathology 93:S54  Publication #: P-2003-0593-AMA (same title as previous, but different content)

Stewart, E.L., N.G. Wenner, L.A. Long, and B.E. Overton. 2003. Petri and esca disease fungi in declining grapevines in Pennsylvania and New York. (Abstr.) Phytopathology 93: S81 Publication #: P-2003-0391-AMA.

Stewart, E.L., N.G. Wenner, and B. Hed. 2003. First Report of Phaeomoniella chlamydospora on Vitis viniferaVitis lambrusca, and French American Hybrids in Pennsylvania and New York. Plant Disease 87:750.

Wenner, N.G., W. Merrill. 1998. Pathological anatomy of needles of Pinus strobus exposed to carbon-filtered air or to three times ambient ozone concentrations, or infected by Canavirgella banfieldii. Canadian Journal of Botany 76(8):1331-1339.

Merrill, W., N.G. Wenner, and J. O'Donnell. 1997. "Canavirgella banfieldii needlecast of Pinus strobus in Michigan." Plant Disease 81:231.

Merrill, W., N.G. Wenner, and R. Kelley. 1997. "Delphinella balsameae tip blight of Abies lasiocarpa in Vermont." Plant Disease 81:229.

Wenner, N.G., and W. Merrill. 1997. "Phyllosticta multicorniculata on Abies spp. in the northeastern U.S." Plant Disease 81:230.

Merrill, W., N.G. Wenner, and T.A. Dreisbach. 1996. "Canavirgella banfieldii gen. & sp. nov.: A needlecast on pine." Can. J. Bot. 74: 1476-1481.

Merrill, W., and N.G. Wenner. 1996. "Biotic agents associated with ozone-damaged foliage of Pinus strobus in the northeastern U.S." pp. 61-67. In: R. Cox, K. Percy, K. Jensen, & C. Simpson (compilers). Air Pollution and Multiple Stresses. Can. For. Serv. Atlantic Centre, Fredericton, NB. 402 p.


Wenner, Nancy G. & Elwin L. Stewart. 2007. “Coming Clean–Grape Meristem Tip Culture." Wine East: May/June 35(1) 10-23 & 56.

Stewart, E.L., N.G. Wenner, L. Long, and B.E. Overton. 2005. Crown gall of grape: understanding the disease, prevention, and management. Stewart, E.L. and N.G. Wenner. 2004. Website:  (Link to PDF brochure on project website) 

Grapevine Decline in Pennsylvania and New York. Wine East: July-Aug 32(2) 12-21 & 51. Stewart, E.L., J.W. Travis, N.G. Wenner, B.E. Hed, M.l. Chien, and A.J. Muza.  2001.

Grapevine Decline in Pennsylvania and New York: A Guide to Symptoms and Understanding the Disease. Informational bulletin © The Pennsylvania State University, 2001.

Albers, M., J. Albers, J. Cummings-Carlson, L. Haugen, and N. Wenner. 1996. Pest Alert: Rhizosphaera Needle Disease of Fir. United States Department of Agriculture, Forest Service. Northeastern Area. NA-PR-06-96.

Albers, M., J. Albers, J. Cummings-Carlson, L. Haugen, and N. Wenner. 1996. How to Identify and Manage Needlecast Diseases on Balsam Fir. United States Department of Agriculture, Forest Service. Northeastern Area. NA-FR-02-96. 10 pages.


Wenner, N.G. 1987. The effect of chlorothalonil on the infection of Scots pine by Cyclaneusma minus. MS thesis, The Pennsylvania State University, 19 p. © 2011 College of Agricultural Sciences.



Population Genetic Structure and Chemotype Diversity of Fusarium graminearum Populations from Wheat in Canada and North Eastern United States
Toxins, Oghenekaro, Abbot O., Oviedo-Ludena, Maria A., Serajazari, Mitra, Wang, Xiben, Henriquez, Maria A., Wenner, Nancy G., Kuldau, Gretchen A., Navabi, Alireza, Kutcher, Hadley R., Fernando, W. G.Dilantha, 2021

Root cortical anatomy is associated with differential pathogenic and symbiotic fungal colonization in maize
Plant, Cell and Environment, Galindo-Castañeda, Tania, Brown, Kathleen M., Kuldau, Gretchen A., Roth, Gregory W., Wenner, Nancy G., Ray, Swayamjit, Schneider, Hannah, Lynch, Jonathan P., 2019

Deoxynivalenol biosynthesis-related gene expression during wheat kernel colonization by Fusarium graminearum
Phytopathology, Hallen-Adams, Heather E., Wenner, Nancy, Kuldau, Gretchen A., Trail, Frances, 2011