Vineyard pest management pros share their opinions and strategies regarding the most
common pest problems, the products they use, organic farming and the future of viticulture.

Having a group of vineyard managers in my home and listening to their conversation was like listening to a group of foreigners talk amongst themselves. They speak the code of rootstocks, the numerology of clones and the mumbo jumbo of herbicides, fungicides and organics.

Over the course of the afternoon I learned quite a lot: I can now distinguish between various fungicides, such as inorganic, contact, sterol inhibitors, strobilurins and quinolines. How these products are used in keeping a vineyard healthy and pest-free is a delicate balancing act.

My expert jugglers in this balancing act included Jon Kanagy, partner in Nord Coast Vineyard Service in Napa. Jon has a degree in horticuture from Purdue University, another in plant protection and pest management from UC Davis and spent two years teaching sustainable agricultural practices in Central America.

Steve Sangiacomo was born and raised in Sonoma, working in the family vineyards. A graduate of St. Mary's College with degrees in business and economics, he is in charge of vineyard and business operations for Sangiacomo Vineyards.

Joe Votek has 23 years' experience as a viticultural consultant and vineyard manager running his Loma del Sol Vineyard Management Company in Sonoma. He graduated from the University of Arizona with a degree in agronomy and plant studies. Also a winemaker, Joe has produced his Bald Mountain Zinfandel since 1992.

We also had Jill Scott from Dow AgroSciences as our product expert. Jill graduated from Cal Poly San Luis Obispo, majoring in fruit science with a minor in agricultural business. She has worked as a sales specialist for Dow in Sacramento for seven years.

There is so much to know when it comes to vineyard pests and their control. How and where does one go about learning it all?

Sangiacomo We're a family vineyard. We're private applicators, so we are required to take continuing education classes every year to keep our license. We attend the annual seminar put on by the Sonoma County Agriculture Commission. There are Internet classes that we take as well as classes at UC Davis on different topics. We sell to 50 different wineries, so there are a lot of other viticultural brains that we are picking on a daily basis, as far as new techniques we can use to better treat our land, our vineyard and improve the quality of the grapes we produce.

Kanagy I come from a background of horticulture in college. After Peace Corps work, I moved to the Napa Valley with my wife and that's where I got involved with viticulture. I have a degree from UC Davis in plant protection and pest management, and lots of information comes from seminars and conversations with colleagues. I came from the background of studying a lot of organic agriculture. I didn't realize that there was a dilemma as to how something that is organic, whether it be a pesticide or a non-chemical treatment like cultivation, fits into the same building. In other words, I wonder if organic is the best way to go.

Votek We're farming 10 very unique pieces of property, most of them up in the hills. I want each one of those properties to be productive and not have a negative impact on my surroundings. The way of getting there is a road that has many different paths. Out of those 10 properties, we have one that is organic because the owner feels very strongly about the use of synthetic pesticides. I think that some of our other properties have even less of an impact than our organic vineyard does. The practices that we use make it a little different from property to property, season to season, because it is a very dynamic, totally changing scene that we have out there. We don't know what bud break is going to give us. Are they going to burst and flow through that period of short shoots, or are we going to have a slow growth and have to worry about cutworms and thrips and having to treat. Most years we don't treat for anything other than mildew, but it's a moving target.

Scott Being a manufacturer, we want to educate people, not only on our materials, but on what's new, what's current and what's effective. We offer meetings and continuing education through the Department of Pesticide Regulation because, if you are a private applicator (PA) or a licensed pest control applicator (PCA), you must have so many continuing education hours per year. For a PCA, it's 40 hours every two years; a PA needs 10 hours per year.

What are the most common pest problems in vineyards?

Votek Mildew is the most common problem we have, in varying degrees, year in and year out. Most years in the North Coast you can't grow quality winegrapes without treating for mildew. That's our number one pest problem. Traditionally we only use sulfur and copper, so we treat seven to 10 times each year.

Scott But if you do incorporate Rally or Quintec or other conventional material, it lasts longer between applications.

Sangiacomo For mildew we mostly use sulfur. Later in the season we have gone to other fungicides because some winemakers have had sufide issues in the wine. You have to keep a tight program with sulfur. Some of these other products give you more latitude, but we've had great success with sulfur.

Kanagy We use a combination of things. We use sulfur up to about bloom. Then we'll mix in some other things like Abound or Flint, which are strobilurins

Scott These are all fungicides. There are several classes. Strobilurins are one class. DMIs or SIs (sterol inhibitors) are another class, and quinolines are yet another. Organic materials like Serenade are another class and so are inorganics, like sulfur.

What are the differences between sulfur and these so-called "conventional" products?

Scott They all work differently on the funguses themselves. Sulfur is more of a contact type of material; it doesn't give you the longer residual activity that you would get with the others. You're going to get 10 days with the sulfur, and rain can wash it off. The other materials last two to three weeks.

Kanagy I mix things. I like to use sulfur early in the season, but it has a huge disadvantage later in the season. Sulfur and a lot of heat give a high risk of burning, and can lead to more spider mite problems. Finally, used closer to harvest, sulfur can leave residues on the grapes. Some wineries have restrictions against wettable sulfur after bloom and no sulfur at all within 30 days of harvest.

Votek Some wineries believe there is a problem with sulfur and H₂S in wine. I know wettable sulfur can cause problems, but I have never seen direct evidence proving that dusting sulfur causes H₂S, especially if you stop using sulfur at veraison.

Scott All of the fungicides, if used properly, work very well, but you have to know their limitations. Some only last two weeks, some three weeks. We want people to use sulfur. We want them to rotate chemistry. If they start off the year with sulfur, great. Then they can move into Rally at bloom and then another class of material after that, depending on what their preference is. We like them to use all of the materials in a program approach.

When you are rotating chemistries, you maintain effectiveness. With Bayleton, so many people used it year after year, application after application, cutting corners, etc. The material failed. It no longer works.

If mildew is the number one problem, what's next?

Votek Weed control. Weeds provide unwanted competition and a habitat for other pests, such as moles, voles and gophers. You don't want weeds growing up into your fruit zone.

Kanagy It's pretty easy to mow or cultivate between the rows, but right in the row, it's very difficult. There are a number of mowers that are supposed to work within the row, but they don't do a very good job.

Sangiacomo I'll make a small point about weeds. Visuals add a lot to a vineyard. Wineries frown on seeing weeds competing with the vines, even though it's hard to prove that they are actually taking material away from the grapes.

Scott Obviously, there are herbicides, such as Roundup and Goal, to control weeds. Roundup would probably be the number one choice.

Votek Number one used and abused. We're too dependent on it, so we're using more mechanical weed control even though it is more costly.

Scott There's Gramaxone; you guys probably use some of that.

Votek Worker safety is an issue with Gramaxone. You can't just let a guy go out there. You need somebody you can trust, like your brother, because it's a dangerous material.

Scott Gramaxone remains another herbicide option, especially if you are concerned with the effects of Roundup. It's only dangerous when NOT used according to the instructions.

Kanagy All of these things are pretty straightforward, but depending on whether it's in Pinot Noir in Carneros or Cabernet in Rutherford, the program varies a lot with powdery mildew. It varies according to variety and location. We also treat preventatively for Botrytis in some years.

Scott Some of the same materials that work for mildew can also suppress Botrytis, but for serious problems, there are specific materials available. Abound and Elevate are the two most popular Botrytis materials.

Sangiacomo We've found that the best thing for Botrytis is leaf removal and shoot positioning. It allows us to get sunlight and air to penetrate into the vine canopy.

Votek We haven't had to do any Botrytis control in 10 or 12 years because of canopy management. We did have some vineyards that had Botrytis problems in the past, but once we started opening up the canopies, we've not had a problem.

Do you have to worry about removing too many leaves in what turns out to be a cold year?

Votek That could be a problem, but with experience you avoid that problem. We're careful about the level of vegetation we remove. We're also managing where the growth is, so we've gone to more vertical canopy versus the old sprawl canopy, and that helps a lot.

What other pests cause problems?

Kanagy Leaf hoppers. They're in every vineyard, every year, but it's hard to know when you need to treat for them.

ScottLeaf hoppers always seem to be there. It's just a question of whether they are causing damage.

Votek In some springs that are cool, when the vines are growing slowly, they are susceptible to cutworms or thrips. Oak root fungus is a localized problem, especially in shallow soils where you are using a lot of water.

Sangiacomo We've also had to deal with spider mites. It seems that mites have hot spots and reappear in the same areas. It might be a dust issue where we need to water the road or change our leafing timing. We can remove a lot of mites with that.

Votek We have some chronic hot spots for mites, especially on some of our dry-farmed sites. We have a couple of knobs that are water-stressed, and the mites hit there first. So we've gone into a preventative program in those cases. As soon as we see any mites at all, we hit them with JMS stylet oil at least once or twice, and it doesn't nuke them like Omite but it keeps them under control. We can get through the season and ripen a nice crop whereas, if we did nothing, we'd have defoliation.

We've been talking about pests for 30 minutes. No one's brought up the glassy winged sharpshooter.

Scott It's definitely hit hard in Southern California, and there's been a bit around Sacramento.

Votek It has the potential of being a problem, but it hasn't really shown up in Sonoma County, aside from a couple of isolated nursery shipments that the Ag Commissioner's office found in time.

Sangiacomo There's a lot of trapping going on, a lot. And they do trap the hot spots, too, like new landscapes coming in, new communities. That's where they are concentrated. The primary source is probably going to be from nurseries.

Scott I think mealy bug is the bigger issue. There are three kinds: grape, obscure and vine. Vine mealy bugs have the biggest chance of being a problem because they can get into the root system. It multiplies extremely quickly, and it's much more difficult to get a product down into the roots.

Kanagy They can contaminate the fruit. We managed a vineyard last year that had a bit of vine mealy bug. The Ag Commission has a protocol that they ask people to follow in the face of an infestation. We removed infected vines, stripped bark, washed down trucks and equipment, and then did a post harvest spray with Lorsban.

Votek I think the consensus is that currently there is no non-chemical treatment for vine mealy bug, so it is potentially a huge problem, especially for those of us trying to adhere to organic practices.

What kind of organic farming appeals to you?

Kanagy Cover cropping is key to feeding the soil. Whether you disc or mow, cover crops are the most efficient way of putting carbon back into the soil. We also like to use some compost, about two to five tons per acre. Wineries produce some compostable waste, which can help keep the cost down.

Sangiacomo Everything we do, whether it is organic or not, has to do with balancing the overall health of the vine and yield. Too much fruit hurts the vine by draining it of essential energy resources, while too small a yield encourages over-abundant growth, leaving not enough energy available to ripen the fruit.

Votek The best way to produce healthy, vigorous vines is to have healthy, alive soil. Most of our focus is on adding green manure using a cover crop like legumes, which are high in bio-mass. We use the cover crops in rotation, especially on the hillside vineyards where I need to be concerned with erosion.

You all deal with dozens of wineries. What are the biggest current demands?

Kanagy For us, it has to deal with maturity, the degree of ripeness. Wineries seem to want higher sugars each year, and this makes a big difference in how you handle the vineyard. The industry is coming up with some creative contracting ideas, like higher prices for higher sugars and grape prices related to bottle price or the actual amount of alcohol. We also work with specific acre contracts where the winery pays a certain price per acre. Then we farm it to do what they want, and the tonnage the vines produce is what they get, but the per-acre price stays the same.

Votek Some wineries used to make a big deal about minimal irrigation, but with the longer hang times and the newer rootstocks, much of that concern has dissipated. They see the need for water in the vineyard. The biggest difference between wineries today is determining ripeness. Personally, I think this trend toward ultra-ripe fruit is a negative.

Sangiacomo Almost all of our wineries like to use some sort of deficit irrigation techniques. Wineries seem more concerned with the red wines, feeling that deficit irrigation develops better color and balanced tannins. It's tricky because each vineyard is different. We have to consider soil, terroir and variety. Usually we can be more aggressive with deficit irrigation in deeper soils. With shallow soils we have to be more cognizant of the health of the vines, so we're less aggressive.

What do you see in the future for viticulture?

Sangiacomo I think most current viticultural techniques are sound and will continue, but I expect pretty soon we'll start looking to the past. We'll see what people used to do and see if that can'tbe worked into the system. You watch, pretty soon people will begin experimenting with the California sprawl as a canopy technique. What goes around, comes around, even in viticulture.

Kanagy I think we'll see more specific contracts in response to wineries insisting on longer hang time and higher sugars.

Votek And then when it comes to vineyards, there are two pests we haven't discussed: people and urban development. But that's another interview.

As long as there is agriculture, man will have to deal with pests. When it comes to vineyards, most growers seem well aware of the need to balance the control of these pests with the greater good of the land. Part and parcel of being a modern viticulturalist is taking care of the environment. I feel very comfortable relying on people like our panelists to make the judgments regarding what is best for the grapevines and ultimately the wines we make from the grapes those vines produce.

Clearly, winemakers with more knowledge of the vineyards, who spend lots of time in those vineyards, have the advantage when it comes to making fine wine. I think it would help growers if winemakers had a better understanding of the problems growers face.

In the end, growers and winemakers are partners. They help one another. The better they understand each other's problems, the better the finished wines will be. wbm