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September 2017 WINES&VINES 69 WINE EAST WINE INDUSTRY NEWS what grew were the five-cell co- nidia of Pestalotiopsis. Her next step was to look at other fruits, and she found cluster stem wilt in blueberries that was similar to the Pestalotiopsis problems she had seen in grapes. In 2016, she learned about Volenberg's discov- eries in Missouri. Trunk disease, then fruit rot: What's next? Volenberg first saw and then identified Pestalotiopsis in a Nor- ton vine with trunk disease near Hermann, Mo., in June 2015. A few weeks later he visited an- other vineyard where a grower was seeing rot on clusters after lots of rain. "The grower didn't think it was black rot," Volenberg said. "It looked like bruised fruit." After reviewing the grower's spray program, he suggested in- cluding use of Pristine. After it was applied, the affected berries dried up and dropped off. He later confirmed the culprit was indeed Pestalotiopsis, The extension specialist did some research and found that Pestalotiopsis had been identified in table grapes in China. He also located a paper, "Characterization of Fungal Pathogens Associated with Grapevine Trunk Diseases in Arkansas and Missouri," by J.R. Urbez-Torres et al. (2012), that identified Pestalotiopsis as the second most prevalent fungus in vineyards in those states. In 2016, Volenberg received reports of leaf discoloration on young leaves of both Norton and Chambourcin in mid-May. In his newsletter in mid-June, Volen- berg recommended Missouri growers include strobilurins such as Pristine, Abound and Flint, and also mancozeb in their spray pro- grams because Pestalotiopsis can cause fruit rots as well as trunk and leaf problems. Teamwork in 2017 Morton and Volenberg decided to work together to develop a better understanding of this apparently ubiquitous fungus. In both re- gions, the fungus seemed to re- quire rain to get sporulation, and as a result, Pestalotiopsis probably will not be a problem in dry cli- mates such as California. Morton and Volenberg did laboratory testing to evaluate the growth of Pestalotiopsis on po- tato dextrose agar and also the growth of Pestalotiopsis in the presence of mancozeb and pyra- clostrobin in Petri plates. The results indicated that growth of Pestalotiopsis was substantially inhibited, even with low levels of the fungicides. Volenberg's work with Norton that suggests that the symptoms of Pestalotiopsis are transient and may succumb to the heat in sum- mer. "It may be a weak pathogen," he said. "It hangs around until the conditions are right." According to Morton, many questions remain about Pestaloti- opsis. "We should look at cultural practices," Morton said. "Trunk disease may result from mechani- zation. Is that making diseases worse or more significant?" Grow- ers need to remember that not every black dot is phomopsis, and not every rot is black rot. They should watch out for Pestalotiop- sis, especially if they want the vineyard to be organic. —Linda Jones McKee LUCIE MORTON Symptoms of Pestalotiopsis include red rachis, berry shrivel and stripes and dots on the cane.