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Faculty Focus

Five Questions for Tim Martinson

By Tim Martinson, questions supplied by Chris Gerling

Tim Martinson was senior extension associate and leader of the Statewide Viticulture Enology Extension Program before his retirement on January 31, 2022. After obtaining his PhD in Entomology in 1990, he started working with grape research and extension in 1991 as a research associate in the grape entomology laboratory at Cornell AgriTech.  In 1997, he became area extension associate with the Finger Lakes Grape Program, based in Penn Yan, NY. At the end of 2006 he was appointed senior extension associate at Cornell AgriTech, where he created and edited the Appellation Cornell quarterly newsletter and the weekly Veraison to Harvest seasonal newsletter annually from September to October.

You started your extension job with the Finger Lakes Grape program after several years as a research associate in Entomology. What was your biggest surprise when you started in extension?

My first thought was “what am I doing here?” I may know a lot about grape insects, but I don’t know much about grapevine pruning, training systems, nutrition, disease management or any other growing practices.  And I’m going to be telling folks who have been growing grapes for generations what they should be doing?  I don’t know how to grow grapes!  But as I got involved in on-farm projects early on,  I realized that I wasn’t expected to know everything.  What I did know was how to run vineyard research trials – to establish different treatments, collect data, and write about it for the industry.   This led me to participate in field trial projects and surveys involving ‘millerandage’, boron nutrition, atypical white wine aging, winter injury, leafroll, shoot thinning, variety evaluation – among many others.   I worked with many grower cooperators on these projects – and I found that growers valued these projects and the data and insights they provided.

What are the characteristics of research projects you feel are most useful to the industry?

Both short-term applied practical trials and longer-term more basic research are important.  Disease and insect management ‘spray trials’ are foundational.  During the growing season, pest management is foremost in grower’s minds.  They rely on our information to make informed decisions about what to use and when to manage diseases and insects.  But longer-term more basic research also provides benefits that are not immediately apparent – but bear fruit later on. 

A classic example is the research David Gadoury did in the 90s defining when powdery mildew spores were capable of infecting grape berries.  He bagged clusters weekly to isolate them from field sources of infection, sprayed them with spore suspensions, and measured the resulting infections.  He found that ‘chardonnay’ clusters became resistant to infection about 5-6 weeks after bloom. This provided a well-defined ‘window’ for spray programs (prebloom to 2nd postbloom) that allowed growers to better target powdery mildew sprays (see Appellation Cornell article “Climate, Duration of Bloom, and the Window of Risk for Grapevine Diseases.”) 

Another example is Gavin Sacks and Justine Vanden Heuvel’s work on methoxypyrazines (MPs) (associated with ‘bell pepper’ unripe, vegetal aromas in red wines) production and metabolism (see Appellation Cornell article “Cornell Researchers Tackle Green Flavors in Red Wines”) .  Again weekly MP sampling by Sacks and a leaf-removal timing trial by Vanden Heuvel showed the importance of early cluster-zone exposure to limit production of MPs and reduce undesirable MP flavors.

Finally, cheap DNA sequencing data has – in the past 10 years – allowed grape breeders to identify genetic markers associated with powdery mildew and downy mildew resistance.  They have found at least 10 powdery mildew and 27 downy mildew markers (see figure below)  that are associated with resistance (See Appellation Cornell article “The Core Grape Genome and Cheap DNA Sequencing:  A New Roadmap for Grape Breeders”). For the first time, breeders such as Bruce Reisch can determine which seedlings have which resistance genes – and select those with multiple resistance genes or discard more seedlings before planting them out in the vineyard.  This is a huge jump in efficiency – and will result in better, disease-resistant varieties over the next 20 years and beyond.

Powdery and downy mildew resistance markers identified since 2000.
Figure from Wines & Vines article " The Phenotyping Bottleneck: How grape breeders link desired traits to DNA markers ", published December, 2018.

What advice would you give to someone planting a vineyard in New York today?

Experience tells me that site selection is the most important consideration.  Climate and soils determine site suitability – and dictate what varieties can be grown where.  But local climate – also known as mesoclimate (but sometimes referred to as ‘microclimate) trumps soil characteristics, because it’s something a grower can’t change.  Pinot Noir and Riesling won’t survive in Northern New York – or more than a few miles away from the Finger Lakes, Lake Erie or Lake Ontario.  But the good news is that new cold-hardy ‘Minnesota varieties’ have provided an option for areas with frequent sub zero winter temperatures.  Topography is another important aspect of site selection:  good air drainage is important for avoiding spring frosts and for disease management.  Slopes are the best, valley floors are the worst.

Soils have to be suitable as well. Drainage and soil pH are key. The best soils (and traditionally the best sites) are well-drained gravelly or sandy loams. But drainage can be improved by installing tile lines, and pH can be corrected with lime.

Which brings me to the second piece of advice:  Site preparation is important!  One of the big changes I’ve seen is the adoption of intensive ‘pattern tiling’ for new vineyards.  It’s expensive to install branch lines every 18 ft (2 rows), but results are impressive.  Instead of ragged up-and-down, up-and-down vine size, sites with intensive tiling have more uniform growth.  Preplant weed management is also important – seeding a vineyard with a cover crop the year before planting will shade out weeds, and make weed management easier during vineyard establishment.  For novice growers, failure to limit weed growth is a frequent cause of failure or delayed growth.  The bottom line:  Spend the money up front! Pattern tiling and site preparation is expensive, but continues to pay off (in earlier, better yields, more uniformity) for the life of the vineyard.

What advice would you give to someone starting out in viticulture research or extension today?

Job number one is getting to know the industry and establishing relationships with growers and other industry professionals.  If you can establish good relationships during the first year, the trust you garner will follow you through your career. Conversely, if you start off on the wrong foot, some will remember it forever. First impressions matter.

The second piece of advice is to establish on-farm trials, surveys, or demonstration projects that get you out collecting data frequently in growers’ vineyards – and puts you into frequent contact with them.  This is the way that both you and the grower learn and generate ideas that can later be shared more widely.

Finally, recognize that your extension/research program is by nature a collaborative effort.  For me, one of the rewards of being in extension has been the opportunity to participate in both the research/academic world and the grower’s more practical and hands-on world.   Ideas come from many places – growers, researchers, and extensionists all have unique perspectives and qualifications.  I’ve appreciated all I’ve learned from growers and the numerous research programs associated with enology and viticulture.  There’s power in collaboration.

What do Cornell Cooperative Extension grape and wine programs need to do more of in the next 10-20 years?

Climate change, labor, and profitability are three issues that come to my mind.  In terms of grape production, warmer temperatures (especially at night) and more frequent and variable rainfall are the big challenge.  While a longer growing season could make it easier to ripen grapes more consistently, humid post-veraison weather will lead to more late-season disease pressure.  Downy mildew will be more important, and we could see severe sour rot outbreaks more frequently as the climate changes.   Less labor availability for manual pruning and canopy management tasks will increase the pressure to mechanize more vineyard tasks.  Profitability is always important – and both research and extension need to keep a laser-sharp focus on the businesses we serve – whether it be juice grape growers and processors, bulk wine/grape producers, or wineries, large or small.

Over the past 25 years of my involvement with the industry I’ve seen many changes.  Concord growers have adopted mechanical pruning, mechanical crop thinning with grape harvesters, and multi-row equipment to lower production costs and increase yields.  Terry Bates’ Efficient Vineyard Project is providing growers with new tools for precision viticulture.  Vinifera growers have adopted new training systems such as ‘Scott-Henry’ training and increased the precision and timing of canopy management (hedging, shoot positioning, cluster-zone leaf removal). Quality has improved markedly.  Wineries (small and large) have adopted new winemaking practices – and increased the sophistication and reach of their marketing and sales.

For me, this underscores the key role our research and extension programs have played in fostering these changes.  Nelson Shaulis’s pioneering work in light interception and canopy density sparked a world-wide change in vineyard canopy management practices.  Bob Pool and Terry Bates’ work on vineyard mechanization has kept the Concord/Niagara juice grape industry competitive with producers in the West.  Gavin Sacks and Justine Vanden Heuvel’s efforts made growers prioritize leaf removal for reds shortly after fruit set, rather than ‘whenever’ – leading to better quality of red wines such as Cabernet Franc.  Our pathologists and entomologists provide continuing trials and advice on current and future disease and insect challenges.

When I started in extension, my initial impression was that growers would be very conservative and slow to adopt new practices.  But I soon realized that this wasn’t true at all.  My experience is that growers’ practices – from canopy management to floor management to insect and disease management – can and do change rapidly, and that the research and extension efforts at Cornell are valued and used by industry.   For me, that has made for a satisfying and rewarding career in extension.

Tim Martinson is senior extension associate emeritus (retired) in the horticulture section of the school of integrative plant science and Chris Gerling is senior extension associate in the department of food science, based at Cornell AgriTech in Geneva, NY.