Time of Pruning May Be a Significant Factor in the Months Ahead
Watch Out for Multicolored Asian Lady Beetles
Upcoming Grape & Fruit Meetings
Dr. Stan Howell Wins National Award
Michigan Grape & Wine Industry Council
Overview of Grape Diseases During the 2003 Growing Season
Three Successful Wine Grape Grower's Tours
Vitculture Field Day's Photos July 2003
Fruit Meeting Calendar

Two years ago, a new ladybeetle became a pest for homeowners and fruit growers in this region. Large populations of the multi-colored asian ladybeetle, Harmonia axyridis, were formed after feeding on aphids in woods and field crops all summer, but then they caused problems by moving into homes and vineyards in the fall. Their presence in grape clusters close to harvest was probably in search of sugars and to find a tight space for overwintering. However, these ladybeetles could then be harvested along with the fruit, releasing a defense chemical when crushed. Human senses are very sensitive to these chemicals and they cannot be filtered from wine or juice.

This pest was not seen during the 2002 harvest, but a few beetles have been seen in vineyards in late September 2003. If these beetles are seen in the clusters, the level of infestation should be determined, and appropriate action taken if fruit quality is at risk. Fruit infested with only a few beetles immediately before picking can easily be removed by hand-pickers. This may not be economically feasible on a large planting, and growers may have to resort to other tactics. Camphor and menthol have recently been shown to repel adult beetles, but their activity lasted for only a short time and no commercial formulations are yet available.

If beetles reach pest levels in a fruit planting before harvest, insecticides applied for other near-harvest pests may allow growers to achieve insect-free fruit during harvest. Repellent pesticides applied for pre-harvest removal of other beetle pests such as Japanese beetle are likely to control Asian lady beetle infestations. However, the waiting period before re-entry and harvest must be carefully checked before any product is used to allow time for pickers to re-enter and harvest to proceed. Pesticides should be applied only to infested areas to minimize chemical exposure and to conserve some beneficial insects. Many pesticides are labeled for use only by certified, licensed applicators that have received specialized training on the use and disposal of pesticides. These pesticides should not be applied by unlicensed homeowners, and at all times their use should be in accordance with the label.

There are several meetings in Michigan that grape growers should put on their calendars, as well as other fruit meetings of interest. Check out the complete list on the last page of this newsletter. The most important meetings are the grape sessions at the Great Lakes Expo, on December 9th, 2003 and SW Michigan Horticulture days on February 5th. 2004 At this time we are not planning on having a grape session at Ag Action Day January 23, 2004 at KVCC. We will be having sessions on tree fruit, blueberries and small fruit such as strawberries and brambles. There are also several RUP training sessions before the New Year if you need a few RUP credits to re-certify. There are two winter meetings that might not appeal to most grape growers but will be useful to a few who are taking a close look at changing some things on their farms.

One is a 2-day Irrigation Workshop at the SWMREC. This workshop is planned to have general sessions in the morning focused on irrigation in general and then breakout sessions for overhead and trickle irrigation in the afternoons. Grape growers considering irrigation on newer vineyards, on sandy sites or for wine grapes should attend this workshop. The other is a four-week workshop on strategic planning for your farm business called ‘Guiding your Fruit Farm into the Future’. This workshop will meet on Mondays from January 12th, to February 2nd, 2004. The purpose of these meetings are to discuss the changes on both the world and Michigan’s fruit industries and to forecast where you and your farm want to be in 10 or 20 years and how to get there. If you are interested in this meeting please give me a call at 269-657-7745

Grape meeting at Great Lakes Expo, December 9th, 2003. This session is in the afternoon from 2 to 4 pm. This year’s session will focus on some of the problems that were encountered in 2003. Dr. Terry Bates, of the Fredonia Viticulture Laboratory, will speak on ‘Vine Balance: Growth, Crop Estimation and Adjustment’. Dr. Terry Bates, is the only viticulturist to focus on Concord and Niagara grapes, but his research on balancing the vines vigor, growth and crop is applicable to all vineyard situations. Dr. Rufus Isaacs, MSU Small Fruit Entomologist, will review ‘Insect Management in Grapes’. The primary focus of Dr. Isaacs talk will be on Grape Berry Moth. This spring there was winter damage to grapes in Southern Michigan as well as in Northern Michigan. Dr. Tom Zabadal, coordinator of SWMREC will speak on the cultural practices that growers can use to minimize the risks they face in winter cold. Dr. Zabadal will talk on ‘Managing Grapes in Anticipation of and in Response to Winter Injury.’

Dr. Stan Howell, Michigan State University professor of horticulture and coordinator of MSU’s viticulture and enology program, has won the Lodi-Woodbridge Winegrape Commission’s annual Wine Integrity Award. Created in 1998, the Wine Integrity award honors those individuals who have conducted their careers with integrity while making significant contributions to the world of wine.

Dr. Howell, an internationally recognized plant physiologist and viticulturist, was chosen for his more than three decades of dedication to the expansion and improvement of the Michigan wine industry. He received the award at a special dinner in his honor on Oct. 14 at the Wine and Roses Inn in Lodi, Calif.

“Much of Stan Howell’s research has been conducted here in Michigan, where our industry has been fortunate to benefit from the close proximity to leading research on vine physiology,” says Linda Jones, executive director of the Michigan Grape and Wine Industry Council. “While his research contributes to the body of knowledge globally, he and his staff take time to offer educational programs and consultation with the local industry. Two of his doctoral students are now prominent winemakers in Michigan’s industry.”

“Stan could have chosen to take his research to any number of institutions around the world,” says David Miller, winemaker and viticulturst for St. Julian Wine Co., Inc., of Paw Paw, Mich. He worked for Howell while getting his doctoral degree at MSU. “Instead, he chose to stay in Michigan and tackle the more difficult challenge of helping to build an industry in a region that is ‘climatically challenged’ – Michigan. Stan’s efforts are well appreciated by those who choose to stay abreast of the cutting edge in viticulture both at home and abroad.”

“It is hard to know where the Michigan wine industry would be without Stan’s guiding hand,” says Jim Wolpert, head of the Enology and Viticulture Department at the University of California at Davis. Wolpert worked with Howell as a graduate student and field technician in his viticulture research program at MSU. “The impact of his work is felt in every aspect of the industry.”

Howell came to the MSU Department of Horticulture in 1969 as a Michigan Agricultural Experiment Station researcher and MSU Extension specialist. Since then, his efforts have helped Michigan expand its total grape holdings to 13,500 acres, making it the fourth largest grape-growing state in the nation. In 2001, Howell launched the two-year viticulture and enology program within the MSU Institute of Agricultural Technology. The program is designed to train students in grape and wine production, focusing on cool-climate grape varieties. It is the first program of its kind east of California.

Howell has published numerous articles in scientific journals, addressing such topics as wine grape yields, cold hardiness, pest and disease management, and cloning. He has been a lecturer and served as editor of the “Vintner and Vineyard” publication of the American Society of Enology and Viticulture.

Information about Council activities is available to members of the industry on the Council’s web site www.michiganwines.com. The Industry Resources section is accessible only by ID and password, to winery owners and staff and wine grape growers and their staff. Please contact Karel Bush at 517 241-4468 or bushk9@michigan.gov to obtain your ID and password. Recently posted information of interest to growers includes:

- Grape Exchange – buyers and sellers of wine grapes
- Annual Report 2004 – plans for Council programs for the coming year and reports on the recently concluded Strategic Planning activity
- Newsletters

Watch for announcement soon, regarding the date and location of the Annual Wine Industry Meeting. (February/ March 2004)

The 2003 growing season proved to be challenging for both juice and wine grape growers. While the wine grape crop in northern Michigan was decimated by severe winter and early spring freezes, juice grapes were sporting a bumper crop in response to two years of poor yields and high levels of stored reserves in the vines. The crop load in some vineyards was estimated as high as 22 tons per acre, and growers were advised to thin the crop where needed to allow for proper ripening.

Grape diseases provided different challenges. Due to the relatively cool spring, Phomopsis spores were detected in vineyards in southwest Michigan from early shoot growth to well beyond bloom. While disease pressure was probably similar to last year, most growers were prepared to defend their crop using available fungicides and therefore had better disease control than last year. Incidence and severity tending to be higher in hedged vineyards than in manually pruned vineyards. This is attributed to the large amount of overwintered inoculum in older wood retained on the vines in this system. Dense foliage in some vineyards also likely increased disease incidence by creating a humid environment conducive to disease and shielding the clusters from fungicide applications. Both rachis and fruit infections were observed. Most fruit infections originated from infected berry stems, with only some berries showing direct infections through the fruit skin. From the berries that prematurely dropped to the ground, typically less than half were actually infected, which indicates that most berries drop as a result of rachis and berry stem collapse. In field trials in Niagara vineyards in southwest Michigan, programs that included surface-systemic fungicides (e.g., Abound, Flint) after bloom reduced the disease more than those that contained solely protectant fungicides.

Powdery mildew incidence and severity were variable in 2003. ‘Concord’ vines in many locations appeared to have much less powdery mildew on the leaves than in previous years, probably due to the relatively cool spring and summer. However, powdery mildew on the fruit was reported by some growers. The latter indicated early infections that might have been prevented by sprays of effective fungicides (e.g., sterol inhibitors) before bloom. Powdery mildew on wine grapes was primarily a problem on highly susceptible cultivars. Powdery mildew is favored by warm, humid weather, while frequent rains may actually lower disease incidence by washing powdery mildew spores off the leaves and causing bursting of spores in water droplets. While the humidity may have been adequate, the relatively cool temperatures during spring and summer probably suppressed powdery mildew development.

Downy mildew on fruit clusters of wine and table grapes in southern growing areas of the state tended to be more severe this year than in previous years, as temperatures and moisture levels in spring and early summer appeared favorable for germination of oospores that overwintered in the soil. Regular rain events in the spring and early summer also encouraged infection. Interestingly, downy mildew in ‘Niagara’ was generally less severe and appeared much later than expected. Downy mildew was not detected until late August or September in many location. Extended dry periods in southwest Michigan probably contributed to lower foliar disease levels this year.

Black rot tended to be less severe than last year, but was nevertheless common in unsprayed and lesser sprayed vineyards, particularly in ‘Concord’ grapes. Black rot is favored by warm, wet weather. During the bloom and postbloom period, when most infections take place, the prevailing temperatures were somewhat lower than optimal for black rot, which probably explains the lesser incidence and severity this year.

This has been a relatively favorable year for Botrytis bunch rot so far. The disease in juice grapes is primarily associated with the grape berry moth infestation, which creates wounds in the berry skin and allows entry of the Botrytis fungus. Botrytis spores tend to be fairly ubiquitous in the environment later in the season, as the fungus is able to sporulate profusely on dead plant material. Any wounds created by insects or cracking of berries in tight bunches can encourage Botrytis development. Tight-clustered cultivars also provide a moist environment for infection and sporulation, which further spreads the disease. Botrytis bunch rot can be distinguished from sour bunch rot by the presence of grayish brown spore masses at the stem end or along wounds in the berries, and the absence of the vinegary odor associated with sour bunch rot. Frequent rains in August and September can lead to rapid spread of Botrytis in susceptible grape cultivars.

There were three well-attended 2003 wine grape grower luncheon and tour events this past summer.

The first took place at Tabor Hill Winery us on May 29^th. With over 30 in attendance, there were representatives from most of Southwest Michigan’s wine industry. Over a wonderful prepared meal from the Tabor Hill Restaurant, attendees tasted, networked, and gained a better appreciation of Tabor Hill winery and vineyards. After Tabor Hill, there were field visits to vineyards of Bryan Staffin, David Leslie, and Heart of the Vineyard’s Rick Moersch. The afternoon was brought to a wonderful close in the tasting room of Heart of the Vineyard.

Lemon Creek Winery hosted us for our second event on June 19. This time there were 25 in attendance. At Lemon Creek Winery, a second wonderful lunch was followed by a great discussion period on bloom dates, temperature recording, and insect and disease management. The discussion was then followed by a sunny afternoon tour through some of Lemon Creek Winery’s extensive vineyards.

Our last event took place at Karma Vista Winery in Coloma on July 24^th. Joe and Sue Herman were great hosts for this particular event. A catered lunch was followed by a discussion on crop adjustment that brought a new level of understanding on this topic. The afternoon tour to Joe’s vineyards below the winery showed examples of different levels of cropping and a demonstration on how to critically evaluate your vines.

For those of you unaware of these events, we generally meet for an informal lunch. This lunch would then be followed by an afternoon tour to a site such as a vineyard and/or winery. These meetings are designed for all those involved with the wine grape industry in Southwest Michigan. This includes growers, winemakers, suppliers, and agribusinesses. Michigan State University Extension prohibits discrimination in all its programs and activities on the basis of race, color, national origin, gender, religion, age, disability, political beliefs, sexual orientation, marital status, or family status.

Details on each meeting are generally sent out a couple of weeks before a particular meeting. If you would like to be put on the mailing list for these luncheons and tours, please contact Al Gaus at the Berrien County MSU Extension Office (269) 944-4126 or gausa@msue.msu.edu and ask to be added to the wine grape luncheon list.

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