Eastern Winegrowers Face Weird Weather

Wacky spring increases disease pressure in central and eastern vineyards

by Linda Jones McKee and Hudson Cattell
Extension agents in the East and Midwest are warning about botrytis and powdery mildew. Source: Cornell University
Lancaster, Penn.—Tornadoes by the hundreds; rain by the foot. What’s going on here, and what does it mean for the grape crop in the East? Extreme weather has dominated the headlines for most of the spring. More than 1,000 tornadoes have torn through the midsection of the country and parts of the East. Floods have inundated the Mississippi River region. The month of April was the wettest month on record in many areas: 13.52 inches of rain drenched the Cincinnati area. In Erie County, Penn., about twice the average amount of rain fell during May.
Many assume that climate change is to blame for the unsettling weather. Eric Horst, meteorologist at Millersville University in Millersville, Penn., advanced his theory that this has been a La Niña year, the second strongest on record. Horst also pointed out that just as La Niña and its counterpart El Niño are cyclical, this year’s tornado season is not unique. A very active spring pattern caused hundreds of tornadoes and hundreds of fatalities in 1974, and a similar number of tornadoes and even more deaths were recorded during an active pattern in the 1920s.

Grapevines face disease pressure
The East is no stranger to variable weather patterns. North of the Mason-Dixon Line, this has been a cool, wet spring with delayed bud break. To the south, there has been much less rain—Florida has been suffering a severe drought.

Warm weather in late May and early June in the mid-Atlantic region brought heat accumulations back to where they would be in an average year. During the second week in June, most winegrape varieties in the Finger Lakes had moved into—and in some cases—through bloom. In the Lake Erie region, Concord bloom was officially called June 11, four days earlier than usual.

The rain and low temperatures this spring have increased disease pressure in many vineyards, and extension agents and others have reminded growers about the need for a prompt and effective spray program. According to Hans Walter-Peterson, viticulture extension specialist with the Finger Lakes Grape Program and Cornell Cooperative Extension, downy mildew has been showing up in many vineyards.

Walter-Peterson noted, “The biggest disease issue, however, is phomopsis in native and hybrid varieties. This shouldn’t be a total surprise given the early wet weather that we have had this year, but it still is a cause of some concern.”

Michael White, extension viticulture specialist at Iowa State University, reported that phomopsis has been one of the most serious issues in that state as well.

Across the Midwest and the East, extension agents are also warning growers about early botrytis and powdery mildew, urging the timely use of appropriate sprays. There are also signs that anthracnose and other less commonly encountered diseases may be present this year.

Mark Chien with Pennsylvania Cooperative Extension noted that June has been a brutal month in terms of canopy management. After a long delay caused by cool weather, there has been fast growth in a short period of time.  “It took off like a rabbit,” he said. Shoot-thinning to proper canopy density is important every year, but especially in late ones, he pointed out. Yield management is also important in late years.

Wet weather and cool temperatures are not new to the East, and growers have dealt with intense disease pressure in the past. Most growers have the experience to deal with it and realize that the growing season is far from finished.

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