I have served on Elwin Stewart 's project for the past decade, investigating the organisms and circumstances that cause vine decline in grapes. We completed a 3-year vine decline survey evaluating the health of vineyards throughout Pennsylvania and parts of New York , and collected dozens of Petri and Esca-related fungi. Studying these organisms at both morphological and molecular levels, we try to understand their relationships to the vine, to other organisms, and to the environmental conditions that influence disease development and progression. Currently, my work has been devoted to developing methods of producing clean vines through meristem shoot tip propagation. Beginning with heat-treated canes and following up with meristem shoot tip propagation, we hope to be able to offer growers clean vines to plant in Pennsylvania vineyards.

In a former life, my first 16 years at Penn State was on the Christmas Tree Project, working with Bill Merrill, investigating conifer diseases. We initiated the PSU Christmas Tree Pest Management Short Course, and studied conifer needlecasts, cankers and galls, shoot diebacks and root rots.

Overton, Barrie E., Elwin L. Stewart, and Nancy G. Wenner. 2006. Manganese oxidation in Petri disease fungi as a novel taxonomic character. Phytopath. Med. 45: S131-S134.

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

Overton, Barrie E., Elwin L. Stewart, Xinshun Qu, Nancy G. Wenner, Barbara J. Christ. 2004. Qualitative Real-time PCR SYBR Green detection of Petri disease fungi. Phytopathologia Mediterranea 43: 403-410.

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 vinifera, Vitis lambrusca, and French American Hybrids in Pennsylvania and New York. Plant Disease 87: 750.

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

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

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

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

Merrill, W., and Wenner, N. G. 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.

Extension

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

Stewart, E.L. and N.G. Wenner. 2004. Grapevine Decline in Pennsylvania and New York . Wine East: July-Aug 32(2) 12-21 & 51.

Stewart, Elwin L., James W. Travis, Nancy G. Wenner, Bryan E. Hed, Mark l. Chien, and Andrew 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.

1996. Pest Alert: Rhizosphaera Needle Disease of Fir. United States Department of Agriculture, Forest Service. Northeastern Area. NA-PR-06-96. Authors: Mike Albers (MN DNR), Jana Albers (MN DNR), Jane Cummings-Carlson (WI DNR), Linda Haugen (USDA FS), and Nancy Wenner (Penn. State Univ., Plant Path.) 1 page.

1996. How to Identify and Manage Needlecast Diseases on Balsam Fir. United States Department of Agriculture, Forest Service. Northeastern Area. NA-FR-02-96. Authors: Mike Albers (MN DNR), Jana Albers (MN DNR), Jane Cummings-Carlson (WI DNR), Linda Haugen (USDA FS), and Nancy Wenner (Penn State Univ., Plant Path.) 10 pages.

Extension

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.