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Feature Article from the July 2008 Magazine Issue
Grower Interview JON HELD
How Stone Hill matches varieties with disease controls in Missouri
Jon Held studied enology at California State University, Fresno, graduating in 1980. He worked in Switzerland and Ontario, Canada, before returning to Stone Hill as vineyard manager in 1983. Today, Held is vice president and general manager of the winery, overseeing all production and operations aspects of the company. But viticulture remains a big focus. Stone Hill maintains 157 acres of vineyard, where the family grows a variety of native American and hybrid grape varieties ranging from Seyval and Chardonel to Concord and Norton. Held currently serves as vice chair of the Missouri Wine & Grape Board.
W&V: You're growing native grape varieties and hybrids. How are those grapes better adapted to the growing conditions in Missouri?
Jon Held: Missouri has a continental climate, which means we get cold winters, hot and humid summers, summer drought and lots of rain during the spring and fall. To complicate matters, the winters are a temperature roller-coaster ride. Temperatures of 0° to 5°F one week, followed by highs in the 40s to 50s the next week, and then back to cold. The vines grown here must not only be cold tolerant, but must also have the ability to maintain dormancy very well during the warm temperature spikes.
| Stone Hill Winery |
In addition, a lot of our customers simply prefer the flavor profile of the native American grape varieties. Concord and Catawba done in a sweet style are, respectively, No. 1 and 2 in sales for our winery. With good viticulture and enology, some of the hybrids and the Norton variety can make wines that when served blind will satisfy the most sophisticated consumer of vinifera wines.
W&V: You have seven separate vineyards. How do you match grape varieties to each site?
Held: A good part of the reason we have this many vineyard sites is simply due to the topography of the area. We are in rolling hill country. One of the prime considerations in selecting a vineyard site in Missouri is air drainage for natural protection from spring frost. The very best sites for frost protection are on the south Missouri River bluff hilltops. These sites have near vertical drops to the river bottom below, and offer excellent air drainage. Unfortunately, these sites are the most fertile of the hilltop soils and tend to be small (under 40 acres). As you move farther south from the river, you get some larger hilltop tracts, but the soils become shallower with the potential for fragipan (subsurface soil layers that resist water flow and root penetration), and the sites typically have slightly less air drainage potential. We farm a mix of sites encompassing five different soil types.
Unlike California, we cannot simply turn off the irrigation to slow down growth, since we have the potential for significant rainfall during the growing season. Some of our vineyards were planted in the mid-1960s and early '70s, and knowing what we know now, some of the soil/vine combinations would have been avoided. I now avoid putting Vignoles on the river bluff sites, for example, since this white variety can get quite vigorous and has terrible susceptibility to summer bunch rot complex. The river bluff sites are very good for Vidal, Chardonel and Norton. Concord and Catawba are better suited to the weaker soils, since they can become quite vigorous.
Held: I think it is becoming more feasible due to climate change, but I would not want to base a Missouri wine business on it. I remember those winters in the '80s all too well, when it regularly went down in the -20° to -25°F range. It was pretty disheartening to see 75% primary bud mortality on varieties like Vidal and Seyval, and numerous vines killed to the ground. But back then, we were involved in "chemical" farming: year-round bare soil strips nuked by pre-emergent herbicides and totally devoid of earthworms, and an approach to vine nutrition that involved only nitrogen, phosphorus and potassium, and rather heavy on the nitrogen.
W&V: What sort of weather challenges do you face?
Held: We have a saying in Missouri--once you figure out what the weather is going to do, it will change. A really hard winter will likely be followed by crown gall problems on the more tender varieties. Spring is characterized by lots of rain and frequent frost in the valleys or river bottoms. We aren't out of the threat of frost until the last week of April. Thunderstorms, tornados, hailstorms, high winds, high humidity, cold winters--we get it all in Missouri.
Temperatures by July will approach 100°F, with humidity levels in the upper 90% level. During July we jokingly refer to Missouri as "Misery." If you haven't done a good job controlling the fungal diseases by bloom, just close up shop and move away, because you will be wiped out by black rot, downy mildew, phomopsis powdery mildew, anthracnose and then the dreaded summer bunch rot complex of bitter rot, ripe rot, sour rot, macrophoma rot (a fungus that affects stems, rachis and berries) and, depending on the temperature, botrytis.
In 2007 we had a particularly tough year. March 2007 was the warmest March in recorded history for Missouri. By the end of March we had full primary bud break, and on some varieties the secondary buds were also out. By Easter weekend, the temperatures plummeted into the teens. We experienced a full week of temperatures in the 14 to 19°F range. Many of our varieties had four inches of shoot growth and, obviously, all these shoots were toast. Initial estimates put the damage at 95% grape crop loss for the state. Fortunately, many of the hybrid varieties came back with secondary and tertiary crops, and by the time it was all in, the state averaged approximately 40% of a crop.
W&V: What are your main disease pressures, and what do you do to fight them?
Held: We have just about every disease that can grow on a grapevine in Missouri, with the exception of Pierce's disease. The experts say it is creeping northward, so it's just a matter of time as our winters become milder.
It is very important to understand the relative susceptibility for each variety to each of the individual diseases that can occur here, and the specific control methods required. A disease-management program that works on Concord or Norton would be disastrous on Vignoles or Vidal. Varieties highly susceptible to anthracnose, such as Vignoles and Vidal, will receive a dormant application of lime sulfur solution applied shortly before bud swell. Typically we do not apply this treatment every year, just after really wet seasons.
The next threat is phomopsis. The most effective treatment options are Captan or Mancozeb. Early application also will control early infections of black rot. Then we have to be on guard the remainder of the spring for infections of black rot, powdery mildew and downy mildew. The control strategies and susceptibility vary by variety. Basically we have four control programs for broad categories of grape varieties.
Our program changes yearly to avoid fungicide resistant buildup, and we seldom apply any of the newer compounds twice in row. We use just about every fungicide on the market at some time or another, simply to keep those little fungal organisms guessing what we are going to hit them with next. The best recommendation I can give growers in the Midwest and Eastern United States is to consult the yearly Grape Disease Control paper put out by Dr. Wayne Wilcox of the Department of Plant Pathology at Cornell University.
On the positive side, we have our beloved Norton grape--a variety of V. aestivalis. I always apply one early phomopsis spray, just to be safe. If it rains a lot in the spring and I get nervous, I'll hit it with one pre-bloom spray--a combination to target all the various fungi. Usually, but not always, one post-bloom spray timed with the first generation of grape berry moth. Then I completely forget about disease control on Norton for a month or so, regardless of the weather. Maybe another spray, but only if it's really wet. It is truly amazing what you can do with a variety that has evolved for the microclimate.
W&V: How about pests?
Held: Our primary insect pest is the grape berry moth. Vineyards are monitored with pheromone traps throughout the growing season, and control measures are taken when a new generation emerges. With some of the hybrid varieties, you also have to be concerned with infestations of the aerial stage of grape phylloxera. The galls formed on the leaves of some varieties can be so severe in a humid year that they can defoliate the vine if untreated. We have had good control of aerial phylloxera with Endosulfan or Danitol. Other insect pests are cutworms, flea beetles, grape root borers and grape scales. Also, we must be particularly vigilant toward the end of the season for the multicolored Asian lady beetle.
The other big pests we face are whitetail deer, raccoons, groundhogs, squirrels and wild turkeys. After the devastating freeze of 2007, the forests were essentially devoid of acorns, so the deer and squirrels attacked the vineyards like crazy. We have always had a problem with deer, but never in my life did I imagine that squirrels had such an appetite for ripe grapes.
W&V: You've started using some grafted vines. How do you decide which varieties need to be grafted onto rootstock?
Held: One of the relatively new hybrid varieties is Chardonel, which is a cross of Seyval (a complex hybrid with some vinifera parentage) and Chardonnay (pure vinifera). It therefore has over 50% vinifera parentage and a fair amount of susceptibility to phylloxera. The other variety similar to this is Traminette, which has Gewürztraminer as one of its parents. We have planted both of these on 3309 rootstock. In addition, we are also now planting Vignoles and Norton as grafted vines, even though both of these varieties grow fine on their own roots. Several people have reported better yields and less bunch rot when Vignoles is grafted on 3309. Norton has nightmare grape chemistry for anyone enologically challenge d--high malic acid, low tartaric acid and high pH. We are only in the testing stage, but our hope is that we can improve the Norton must chemistry by grafting on rootstocks that tend to take up less potassium.
W&V: What characteristics are you looking for in deciding when to pick?
Held: In Missouri, it is a balancing act between the weather, the grape chemistry and the flavor. This varies by the variety, since some varieties handle rain at harvest better than others. With Vignoles, you really walk a tightrope between ripeness, rain and the potential for excessive rot. With Concord and Catawba, it is all about aroma and flavor--if you can't smell them as you walk the vineyard, they're not ready, regardless of the chemistry. When it comes to Norton, Chambourcin, Chardonel or Traminette, it is just like a fine Cabernet, Syrah, Riesling or Chardonnay. You do everything you can to get the grapes to the optimum level of ripeness for your style of wine. As harvest nears, we are sampling the various blocks every few days for analysis. I helped plant some of our vines 40 years ago, when I was a young lad. With time, you get to know what they can do for you in any given season, provided you keep putting your shadow over the fields.
Loving 'lousy' Norton
 Stone Hill owner Jim Held worked with Norton from the start and championed the grape, but his son Jon is an even more enthusiastic promoter of the variety, and he expanded Stone Hill's plantings to about 28 acres. "It grows so wonderfully in this god-forsaken climate," Jon Held says. In particular, it resists fungus, which is crucial given Missouri's rainy, humid growing season. In fact, it's the one grape variety that Held wants to try growing organically. If Norton is easy in the vineyard, it's difficult in the winery, because the juice tends to have high acidity and a high pH. "There are plenty of examples of Norton wines where they just don't understand how to work with this chemistry," Held says. The wines can end up brown, with a high pH. Other problems that some Norton wines exhibit are under-ripeness and over-use of American oak. Held lets his Norton hang until mid-October, when it's fully ripe, and he uses a combination of American (primarily Canton Cooperage and Seguin-Moreau) and European oak. There's also a single-vineyard Norton aged in nearly all-European barrels. At its best, Held says, "The aroma is very reminiscent of Syrah," though the flavors suggest a Northern Italian red, like Barbera. "I've always loved the thing in spite of its lousy grape chemistry," he says. L.D. |
A resident of the Santa Cruz Mountains, Laurie Daniel has been a journalist for more than 25 years. Although she grew up in wine-deprived surroundings in the Midwest, she quickly developed an interest in wine after moving to California. She has been writing about wine for publications for nearly 15 years and has been a Wines & Vines contributor since 2006.
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