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92 WINES&VINES November 2017 WINEMAKING WINE EAST S pecies of the fungal genus Pesta- lotiopsis are present on grapevines in vineyards east of the Rockies, but growers didn't realize it was the culprit behind some of their problems with foliage blight, berry rot, stem necrosis and trunk disease. It was not until 2012 that J.R. Urbez-Torres, a plant pathologist from Agri-Food Canada, and his associates reported the pathogen's associa- tion with vascular symptoms of trunk diseases and isolated it from symptomatic grapevines that exhibited characteristic dieback patterns. Their article, "Characterization of Fungal Patho- gens Associated with Grapevine Trunk Diseases in Arkansas and Missouri," identified Pestaloti- opsis as the second-most-prevalent fungus in vineyards in those two states. During the past several years, Dr. Dean S. Volenberg, viticulture and winery operations extension specialist at the Grape and Wine Insti- tute of the University of Missouri, and Lucie Mor- ton, a well-known viticultural consultant based in Charlottesville, Va., each found inexplicable symptoms on grapevines, leaves and fruit. Volenberg identified the fungus Pestalotiop- sis in Norton berry clusters and also in a canker on a Norton vine (which caused trunk die- back) and began writing about his findings in his weekly newsletter Vinews (Viticulture Infor- mation News) in 2015. Morton first found Pestalotiopsis on Maryland grapevines in 2009, and when she intensified her investigation of the fungus in 2016, she found Volenberg's newsletters online. The two researchers began to work together as they realized that Pestalotiopsis was causing problems from Missouri to states on the East Coast. They displayed two posters summariz- ing their evidence about the identity and preva- lence of Pestalotiopsis at the American Society for Enology and Viticulture-Eastern Section meeting in Charlottesville, Va., this July. Symptoms of Pestalotiopsis Since 2015, Volenberg and Morton have identi- fied foliar, berry and cluster symptoms (in the absence of grapevine dieback) on both Vitis vinifera and interspecific hybrid grapevines that seem to be caused by Pestalotiopsis. In the Midwest, Volenberg first found the fungus in a Norton vine with trunk disease in June 2015. A few weeks later, he saw rot on clusters that he confirmed was caused by Pesta- lotiopsis. The following year, he received reports early in the season of leaf discoloration, leaves with brown spots or black smudges and leaves falling off 12- to 14-inch shoots. Upon testing, these problems were shown to be the result of Pestalotiopsis. As temperatures rose during the summer months in Missouri, there were fewer reports of problems created by the fungus. On the East Coast, on the other hand, Mor- ton found that the pathogen appeared to be causing the symptoms of berry shrivel and cluster stem wilt later in the season, after vé- raison. Pestalotiopsis also has been associated with rachis infections that result in berry shrivel in vinifera vineyards. See pages 93 and 95 for photographs of Pestalotiopsis symptoms in Maryland and Missouri. Identifying Pestalotiopsis in the Vineyard and the Lab Common fungus found to be causing disease in eastern vineyards By Linda Jones McKee KEY POINTS The fungus Pestalotiopsis has been identified in vineyards from the East Coast to Missouri by two researchers working independently: Lucie Morton, a nationally known viticulturist from Vir- ginia, and Dr. Dean Volenberg, viticulture exten- sion specialist at the University of Missouri. Symptoms of the fungus were found in Missouri on Norton vines and in Maryland on Cabernet Sauvignon. The symptoms in Missouri included leaf discoloration, leaves with brown spots and early rot on pre-véraison clusters; while in Vir- ginia, Pestalotiopsis caused berry shrivel and cluster stem wilt. Morton and Volenberg, who have been working on the Pestalotiopsis problem together since 2016, found using a regimen that included mancozeb and pyraclostrobin sprays such as Pristine often can substantially inhibit the growth of Pestalotiopsis. Research is continuing on topics such as the environmental conditions conducive to Pestaloti- opsis, fungicides for control as well as other saprophytic and opportunistic pathogens not being controlled by current spray programs. AUTHOR'S NOTE This article is based on interviews with Lucie Morton and Dr. Dean Volenberg and on the two posters they displayed and discussed at the American Society for Enology and Viticulture-Eastern Section annual meeting in July 2017.