Grape Disease Management

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Anthracnose on berries







Anthracnose on grape berries. (Photo: Patty McManus)

Every experienced grape grower knows that good disease management program is a crucial component of growing high-quality grapes.  Early season control is especially important, as flowers and small berries are quite susceptible to powdery mildew, downy mildew, and black rot.

Because cold-hardy grape cultivars are still relatively new, we’re still learning about the different cultivars’ resistance and susceptibility to the range of grape pathogens.  Therefore, one of the objectives of the Northern Grapes Project is to evaluate disease resistance and the cultivars’ susceptibility to copper- and sulfur-based fungicides.

Below is a list of resources that will help you build an effective disease management program.

Grape Disease Management Basics (and All About Anthracnose) by Wayne Wilcox, Cornell University and Patty McManus, the University of Wisconsin.  April 10, 2012 Northern Grapes Project webinar.

The Disease Management Puzzle: Putting the Pieces Together by Dean Volenberg, University of Wisconsin Extension – Door County.  June  4, 2013 Northern Grapes News (Vol. 2, Issue 2).

Grape Disease Control, 2013 by Wayne Wilcox, Cornell University.  A rather lengthy document that contains an update and review of how to control grape fungal diseases in the east.  (Will updated this link with the 2014 version once it’s released.)

The 2014 Midwest Small Fruit and Grape Spray Guide.  Contains general guidelines to use as you develop your grape spray program.  Also has information about fruit grower newsletters, pesticide drift, plant diagnostic lab listings, and much more.


Article and resources courtesy of the Northern Grapes Project.

The State of the Wine Industry

by Michael Vincent, winemaker at Wooden Wheel Vineyards

The wine industry in Iowa has experienced extremely fast growth these last 10 years. In 2004 there were 27 wineries, in 2010 there were 94. At the end of 2013 there are 100. The era of rapid growth in the number of wineries is over.

In 2004 Iowa wineries produced 98,903 gallons of wine and in 2005 we sold 82,785. In 2012 we produced 296,909 gallons and in 2013 we sold 263,682. 2013 saw, for the first time, a decrease in the number of gallons sold from the prior year. Although that decrease is small, around 3,000 gallons, we are clearly entering a new phase in our industry.

No longer can we experience growth based on the novelty of an `Iowa produced wine’. Today you can go into your local convenience store, liquor store or Hy-Vee and find Iowa produced wines. Today we must compete with the Merlots and Chardonnays of the world that are on those same shelves to increase our wine sales.

The Iowa wine industry has 3 challenges as we move forward.

  1. Educating the public on Iowa wines.

  2. Improving our winemaking skills through education & research.

  3. Improving the perception of Iowa produced wines.

No doubt these are substantial challenges that will go unmet without a combined and focused effort.

Fortunately, these challenges have not gone unrecognized. We have as an important resource the Midwest Wine and Grape Industry Institute located at Iowa State University. They provide the training, testing and research to help us make better wines. On February 4th the Iowa Wine Growers Association (IWGA) will be testifying before the Ag appropriations subcommittee for additional funding for the MWGII to increase their services and to lay the ground work for a potential research winery at ISU.

To help us improve the marketing of our wines, the IWGA has recently hired Emily Saveraid as the associations’ Marketing Director. This is an important step for the association as we work hard to help our members meet the challenges of the future. Please take advantage of the opportunity to meet her at the upcoming IWGA Conference in March.

The state of the wine industry, from my perspective, appears very to be good and with a continued effort from everyone, can be even better.

Michael Vincent

Wooden Wheel Vineyards

IWGA Board Member


How the industry has fared over the past year

by Lucas McIntire, winemaker at The Winery at Kirkwood

This last year, or the growing season for 2013, I personally felt was the best yet.  Mother Nature was in cooperation with me and my vineyard operations (for the most part).  Yields may have been down (slightly), but quality was through the roof.  I feel that the wines in the tanks now may be our best production to date. The red wines are darker, and the white wines are softer with wonderful aromatics.

To review the industry, I have analyzed the data from Craig Tordsen at Iowa State University.  He has data from the Iowa Winery Production and Sales Reports going back to 2004.  Between 2009 and 2010, winery sales increased nearly 17,000 gallons.  Between 2010 and 2011, they increased by 34,000 gallons. By the end of 2012 there was only an increase of 1,500 gallons and by the end of 2013 annual sales decreased by 3,000 gallons from 2012.  I believe that we may have hit the plateau as for wine sales by Iowa consumers.  There is the notion that more and more people every day are buying and drinking Iowa wine, in turn usually supporting their nearest/local producer.  Yet, these consumers are faced with a plethora of wines to choose from at the local wine shop.  Sales of Iowa Wine are only 5.9% of all the wine sold in state this year.

I was told by one shop manager that, “If my customer has $7.99, I’ll direct them to some Spanish tempranillo, before suggesting some Iowa wine.” So Iowa Wines still have to fight it out on the sales floor with the classic European and New World varietals being sold at cheaper price points.

Gallons of wine sold in Iowa Winery tasting rooms decreased by 2,500 gallons this year.  I would translate this to mean possibly fewer visitors and less spending/volume of sales.  Perhaps this is in refection to trends in the economy with fewer dollars to spend on luxury items such as wine.

The industry outlook over the next year

All the wineries want to sell more wine, and I notice allot of collaboration within the industry as a whole.  Specifically with the organization of “Wine trails” to promote events together as well as community events where towns like Centerville might bring together 10 to 15 wineries to sell and taste wine together in the town square.  Additionally we are winning people over one customer at a time, year after year.  We are educating people one taste at a time on the different varietals which we produce.  The Wine Institute in Ames is now issuing “Iowa Quality” stickers/seals of approval for wines which score over 13 points on the U.C. Davis 20 point scale by a blind panel of 5 judges.  Hopefully this can lend a hand in proving that the wines we make here are equally as delicious as those crafted anywhere else in the world.  Personally I feel we are helping each other as winemakers by sharing tidbits of information concerning yeasts to ferment with, cold soak practices, enzyme and tannin dose rates used in the winery, along with other operational concerns addressed in the vineyard or winery.  We help each other, and like to pass along secrets rather than keep them to ourselves.

Otherwise, 2014 is a new year and hopefully we will sell a lot more wine!

What you’d like to see from industry professionals over the next year

The best event that I attended was a workshop at Ames, (ISU) concerning specific varietals.  I was there to talk about growing and winemaking practices with La Crescent, a fairly new varietal that has very bright aromatics.  It was great to have a forum to discuss variations in the wines presented based on harvest parameters brought forth from the winemakers themselves.  We could evaluate the wines and speak freely together. Of course we (the winemakers) could do this internally on the side, but none of us really make time!  Additionally there were growers and winemakers there from out of state that lent other interesting perspectives.  I missed the workshop on Marquette, but look forward to what the future (this year) might hold.

Lucas McIntire, Winemaker

The Winery At Kirkwood

Maturing of the Iowa Wine Industry

 by Michael L. White, ISU Extension Viticulture Specialist

I still remember that cold day on Saturday, February 19, 2000.  We had a heavy snow the night before.  Around 125 people from all around the state of Iowa showed up to a winegrape growing workshop held at the Odd Fellows Hall in Indianola, Iowa.   The enthusiasm was sky high and everyone left at the end of the day with their marching orders.  Grow grapes, make wine and have fun.

It was not a hard sell.   Many of the people who came to this first winegrape workshop were the pioneers who established the winegrape industry we have today.  Many have vineyards and/or wineries operating today. Many have fallen to the wayside.  What sounded good ended up being too management, labor and capital intensive for their lifestyle.

In February of 2000 Iowa had 13 wineries of which only two had vineyards and making grape wine. There were only hand full of commercial winegrape vineyards in the state covering less than 30 acres.  We ended 2013 with 97 operating wineries and 316+ vineyards covering 1,200+ acres.  The Iowa Alcohol Beverages Division reported 263,682 gallons of Iowa produced wine was sold during 2013.   Iowa wineries now have 5.92% of the retail wine market share in Iowa compared to less than 1% market share we had in 2000.    A 5.92% market share may seem low until you consider that California (58%) and foreign imports (32%) take approximately 90% of the remaining market share in the U.S.


As you can see from the chart above, the Iowa wine industry is starting to mature.  Some of the people who were in their 50’s and 60’s when they jumped into this business are no longer in the business. New vineyards and wineries still appear each year, just not as many as in the early years.  Many of the older enterprises are expanding.  New entrepreneurs entering this industry have more access to knowledge, resources and services than the early pioneers had available.  The early days of the blind leading the blind are now over. The wineries and vineyards of today are moving from a lifestyle model to more of a business model. They are looking at new products, services and amenities that they can market to make money, spread their risk and hire employees.

More Iowa wineries will be offering a larger variety of wines.  We will see more fortified and sparkling wines.  We will also see more fruit and honey wines and hard ciders popping up on the counter.  More unique blends and new varietal wines will  appear.   Quality will increase as our overall wine making experience increases.   Everyone knows that wine is the seed to many more economic activities.  We will see more wineries expand into more or larger event facilities, bed-n-breakfasts, gift shops,  restaurants and offer greater range of entertainment activities.

The future of the Iowa native wine industry still looks good. Our culture is changing.  Beer is no longer king. There is a place for native wine in Iowa’s future. I predict a slow and steady growth that will strengthen our industry over time.  Slow and steady is more sustainable than the fast and wild days of the recent past.


Michael L. White CCA, CPAg, CSW

Viticulture Specialist

ISU University Extension & Outreach

909 East 2nd Ave, Suite E

Indianola, IA 50125-2892

Office: 515-961-6237, Fax: 6017

Cell: 515-681-7286


Midwest Grape and Wine Industry Institute

Wine Grower News


Midwest Wine Comeback

Guest writer, Mallory Hughes, submitted the following piece for Iowa Decanted‘s first issue of 2014.


At the top of the hill a building sits and a red pick-up arrives, its bed filled with oak barrels. A rocking chair on the front porch sways slightly in the wind. On every side of the structure but one, grapevines are lined neatly in rows, the fruit picked for the season and the leaves now dried, have fallen to the ground. The rows of vines rise and fall with the rolling hills, stopping only once the vines reach the sunburnt forest in the distance. This is not Napa Valley, nor Sonoma Valley, nor anywhere in the state of California. This is Swisher, Iowa, at Cedar Ridge Winery and Distillery.

Before Prohibition, Iowa was the sixth largest grape producing state in the nation. But as Prohibition expanded the market for corn and soybeans, wine production fell because decreased demand for wine grapes resulted in destruction of vineyards. There was damage to grapevines from chemical drift from herbicides, as well as a severe blizzard in 1940 that killed a lot of the wine grape crops.

“Jumping to about 2000, the grape and wine industry is trying to restart all over the country,” Craig Tordsen of the Agricultural Marketing Resource Center at Iowa State University said.

Over the past 20 years, advancements in botanical research and breeding at Iowa State University, the University of Minnesota, and Cornell University have made growing wine grapes in Iowa and other Midwest climates possible.

In the 1980’s, the University of Minnesota began a program to produce hybrid wine grapes able to sustain temperatures in the Midwest. However, it was not until 2000 that a research winery and enology lab were established to study all aspects of wine and winemaking.

The grapes created were cold hardy varietals called French-American hybrids. These grapes produce a full crop of fruit which can withstand the cold winter temperatures of the Midwest, sometimes -30 degrees Fahrenheit or colder.

In September 2006, the Midwest Grape and Wine Industry Institute at Iowa State University was established. As a result of Iowa’s rising grape and wine industry, the Institute conducts research on cold hardy grapes, enology research, and developed a quality award program along with an outreach program for growers everywhere.

Perhaps another reason for the increase in vineyards and wineries in the state of Iowa beyond the French-American hybrid grapes and the extension and outreach program is the Iowa Alcohol Beverage Division. Due to the size of Iowa’s wine industry, obtaining permits for vineyards and wineries is still affordable. In states like California, permits can cost well over $500.

In the state of Iowa, there are different permits one may receive to produce and sell wine. A class “A” permit, which is the official state license that is required to own and operate a native Iowa winery, may be purchased for only $25 per year through the IBD.

The other two permits, however, are for established wineries that are looking to do more with their product than sell it at the winery itself. A class “B” Iowa permit allows wineries to sell their product at off-premise locations like farmers markets and special events. The class “C” Iowa wine permit allows wineries to sell by the glass at wine festivals.

The dedication of researchers at both universities made vineyards and wine production in the state of Iowa possible. Without them, Cedar Ridge Winery & Distillery or Fireside Winery might not exist.

In 2000, Cedar Ridge owners Jeff and Laurie Quint bought a plot of land in the countryside in Swisher, Iowa, and planted ten varieties of French American cold hardy grapes. Three years later, fruit was on the vines and wine was ready to be made.

Jamie Siefken, Jeff Quint’s media spokesperson, explained that Quint works as a CFO in Marion. During the dot com burst he was afraid he would never retire, but decided with his wife that a winery would be his first choice if and when he did.

Just 26 miles west of Cedar Ridge sits Fireside Winery on land adjacent to a family farm. In 2005, after researching the Iowa wine industry at Iowa State’s Extension Program, Bill and Rona Wyant planted wine grapes. By 2007, fruit was produced and the doors were open.

“We’re currently corn and soybean farmers. So, we were looking to diversify and had the interest in the wine,” Rona Wyant said. “We decided that we were going to go ahead and jump in and give it a five-year try.”

Harvest season can be anywhere from mid-August to mid-September depending on the year’s weather as it arrives. But before any harvesting can be done, some precautions are taken to ensure the grapes stay on the vine.

For pre-harvest, Cedar Ridge lays nets over the vines to stop birds from eating all of the fruit before it is picked. At Fireside, a canon bursts air at intervals to scare away the birds, and an electrified fence prevents hungry deer from entering the grounds.

For local vineyards, harvesting the grapes is extremely labor intensive. Both Cedar Ridge and Fireside Wineries put out a call for labor.

Cedar Ridge advertises on Craigslist and social media, but sends an e-mail newsletter that goes out to about 9,000 people as well. They pay each picker per pound of grapes picked.

“We were done in three weeks this past year,” Siefken said. “They’ll come out early Saturday morning and start picking. Usually they’ll be done around noon. And then the guys [staff] will process the grapes all afternoon. It’s definitely a long month or two months for the production staff to work.”

Every year, Fireside Winery hosts an annual “iPick iStomp iDrink” event. They put out a notice in the beginning of August to all of the fan club members and anyone who is on the newsletter list asking them to sign up for one of the three or four weekends to help pick the grapes.

“They come out to the main vineyard at 7 a.m. Then, they go through and pick grapes, talk to Zach and the guys when they’re out in the vineyard with them. They’ll talk about what grape they’re picking, what kind of wine that’s going to make, and then we’ll bring them back,” Wyant explains.

After their return to the Fireside tasting room, they receive a t-shirt, bottle of wine, and lunch, all before doing the grape stomp. Typically the 400 spots fill within two days.

While the harvest process is the same for both red and white wine grape varieties, it is the processing that differentiates the end product.

For white wines, the grapes are picked, de-stemmed, and crushed. They are then chilled and pressed, disposing of the excess seeds and skins before using the juice. Juice treatment occurs, testing the acidity or pH, and adding enzymes and sugars, depending on what types of wine are being made. Then the fermentation process begins, adding yeast and fermenting, stopping earlier for sweet wine, but keeping it in the barrel longer for dry wine.

The red wine process is similar but what gives red wine the color and tannins that white wine lacks is the skin. While red wine grapes are also de-stemmed, the skins are left on during the cool fermentation process that allows the juice to absorb the color and tannins from the skins. During that process the sugars or acids are added to create a dry or sweet wine. Once absorbed, the yeast is added and the juice is pressed to remove the skins before aging and fermenting. Due to differences in styles of winemaking, aging in oak barrels is an option, but not a requirement.

Wine grape growing is all about trial and error. One grape variety may be abundant and produce delicious wines, while another seems to fall short. At Cedar Ridge, St. Croix is one of those that just do not seem right.

“It tastes like a vegetable,” said an employee, enjoying a salad in the tasting room on his lunch break.

“Yeah, we’ve started to not do St. Croix,” Siefken said. “It’s also a mess to pick, too.”

The most successful wine grapes at Cedar Ridge, said Siefken, are La Crescent, Marquette, La Crosse, and Frontenac. Three of these are the University of Minnesota’s most outstanding grape varieties that produce award-winning wines.

At Fireside, similar varieties have been successful. Wyant said the Marquette, Brianna, La Crosse, St. Croix, and Frontenac have been the best producers.

Cedar Ridge is the very first winery/distillery combination in the state of Iowa since the Prohibition. When a wine grape fails to meet expectations, they can usually use the fruit to produce spirits instead.  “We’re also a distillery, so we can make brandies, port or fortified wine, and grappas, and other products like that where we can use a less superior variety for other facets of our business,” Siefken said.

Fireside likewise has alternatives for less successful grape varieties. Zach Bott, son-in-law of the Wyant’s and winemaker at Fireside, may create red wine blends using multiple grape varieties.

While the blends are often made with Iowa-grown grapes, imported California grapes allow them to produce dry reds that are more difficult to make with Iowa grape varieties. By importing the whole fruit, the de-stemming and fermentation processes can be completed locally.

Cedar Ridge occasionally imports whole grapes from Lodi, California, located in San Joaquin County. A few days after it has been picked, the fresh fruit shows up on top of the hill in a produce truck that has been pumped full of nitrogen gas to keep the fruit from oxidizing and spoiling on the way.

By importing the whole grape as opposed to juice or concentrate, they feel that they can get a better quality product, Siefken said. But, to further differentiate the winery, Cedar Ridge buys grapes from other Iowa wineries as well.

“We might get more of a yield from year to year, but as we grow as a business, I mean, there’s only one way to do more wine, and that’s to bring in grapes from outside. So there’s a couple Iowa wineries that in the past two years have grown their entire crop for us,” Siefken said.

Doing it all, growing the grape and seeing it out to the end product is something special to all vineyards and wineries in Iowa.

“Something about in the industry, when you tell people that [the grapes] are grown here, it excites people more,” he said. “There’s a lot of competition in Iowa and it separates yourself from others. To be surrounded by 10 acres of grapes there’s just an ambiance for people to be out here.”

Nationally, the Alcohol and Tobacco Tax and Trade Bureau established American Viticulture Areas, or AVAs to allow vintners and consumers to attribute a given quality and reputation with a certain geographic location. In order to qualify for an AVA designation, at least 85% of the grapes used in the wine must have been grown in that region.

The United States has 206 AVAs total, with California carrying 100 of them. Eastern Iowa is included in the Upper Mississippi River Valley (UMRV) AVA that was created in June 2009 and is the largest AVA in the United States at 29,900 square miles. It covers regions in Minnesota, Wisconsin, Iowa, and Illinois. The UMRV AVA represents 32 wineries and 445 vineyard acres.

The US wine industry is commonly associated with California, which has actually taken quite a different form than the industry in Iowa.

One major difference, Wyant says, is that the wine consumption in California is simply much higher than in Iowa, and people there have been consuming dry wines for a long time. She explains that if you give a new wine drinker a dry red wine from a classic French grape variety like a Cabernet Sauvignon, he or she probably will not like it.

“If you do a tasting in California, in the Napa or Sonoma area, you’re going to find it very hard to find a sweet wine. Here, you’re going to find that our wine palettes are a lot sweeter,” Wyant said. “We’re just learning to drink wine, well, not me! But, as a whole, we’re learning to drink wine, so we start off a little bit on a sweeter side.”

Siefken said comparing cooler climate regions to a place like California is like comparing apples to oranges. The grapes themselves are so different that the product will be very different as well.

Regarding varieties of product, he said, “It really all comes down to climate. Iowa wines, we have a short growing season here and we have a cooler climate.”

“Grapevines themselves start off with high acidity and low sugar and during the growing season it develops more sugar, and then the acidity goes down. That determines the style of wines that you can make, based off of the fruit that you have,” he added.

“I think that’s the farmer in us,” Wyant said. “We’re very proud of having grapes that are grown in Iowa that we feel can stand up next to a lot of the other wineries.”

In the last few years, 15 new wineries have opened in the state of Iowa alone. And as of 2012, there are 98 Iowa wineries. According to the Agricultural Marketing Resource Center at Iowa State University these wineries produce more than 240,000 gallons of wine annually.

“The easy sales have been found,” Tordsen said. “Iowa Native wineries need to develop a stronger marketing approach and improved quality if they hope to grow in the future.”

To view the accompanying slideshow, visit Iowa Decanted‘s Facebook page.

Mallory Hughes is a senior at the University of Iowa majoring in journalism and English with a particular interest in writing/editing for magazines.  She is available for freelance writing assignments and open to job offers starting in May 2014.