The Organic Approach

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Amigo Bob Cantisano

In Napa Valley, like the rest of California What is the difference between conventional, sustainable and organic wine grape growing? 

Well, you have the broad spectrum—from the pretty traditional, “spray and pray” approach to the “organic and a little more” that is biodynamics. 

The people in the middle like to use the word "sustainable," given it doesn’t have any definition. If you’re in business today, you’re sustainable, I guess, but I seem to think that what most of those people say is ,"Well I don’t use hard chemicals but I use Roundup." That seems like a common dividing line.

So how would you describe conventional approach?

Spray and pray? That’s what’s been being done, until the organic thing got going in the 90s, It’s pretty much been the common farming practice since the 1950's and that really varies. Each practice or each farming technique has its own variations. 

So to describe conventional farming, at the nth degree, it starts with the concept of replanting a vineyard--which is common. They have to replant them. 

So conventional farmers commonly--at least historically--fumigated the soil after they took out the old grapevine--and then prior to planting the new ones. And those are a mixture of toxins including methyl bromide and chloropicorin and other materials. 

So at any rate, that was very common, It’s not as common any more because it’s so regulated, but historically that was a very common practice. 

So you would fumigate prior to planting to essentially, in theory, wipe out all the pathogens and diseases and weeds and nematodes. 

It’s a little bit difficult to generalize, but there are farms that have planted, without doing any work on their soils, and they would then take a best guess stab at what to fertilize with. And then they would start fertilizing right before or when they planted the grapes. Historically that was done with dry fertilizers. 

The more modern approach these days is to inject liquid fertilizers into the drip irrigation system. And those are all kinds of materials, depending on what the production of the grower is, according to their needs, but commonly they would use some type of soluble nitrogen fertilizer and perhaps other nutrients added with that.

Nitrogren basically forces new growth and stimulates leaves. Then it kind of moves into the realm of disease and pests and weeds. 

So conventionally they use what’s called a pre-emergent herbicide, which is a long lasting herbicide that is applied to the ground, typically in the fall, and effectively sterilizes the soil for a period of time--six months to a couple years, depending on the material. It prevents the growth of weeds wherever it was applied. That’s pretty common still.

So they put pre-emergents down, and then as far as growing the grapes, there are a lot of practices that are identical in all these systems, but really what I think you’re asking is different kinds of inputs. 

Then they would protect their grapes from diseases with fungicides. Many of them are systemic and last a fairly long time--like up to three weeks between applications. They’re broad spectrum. They kill a wide variety of fungi and they’re toxic to soil fungi, the good fungi. 

One of the downsides of this technique is that it kills off your soil biology--which is also true with the liquid fertilizers. And the herbicides. 

And it’s the reason they get such a short life out of grape vines these days--they basically kill the dirt (but that’s a side comment). 

So, at any rate, they use fungicides, systemic chemistry that lasts up to three weeks, and people like that because they don’t have to apply it very often. And that’s through the entire growing season--from about the time the vines have about six inches of growth on them up until veraison is typically when that’s done.

If rain events happen, both at bloom or during the fall, then there’s a problem with bunch rot, which is botrytis, and they would apply other fungicides to prevent or kill botrytis infections. They also put on fungicides when they’re pruning to kill all the butt canker spores and the eutypa spores that enter the pruning wounds.  What else do they use - I guess that’s the main ones. 

Then there’s the insecticides or miticides. 

Mites are not a common problem in the Napa Valley, but they can become one, and so they apply various kinds of chemistry--some of it quite toxic--for controlling mites. And again, typically these days people don’t do that prophylactically. 

Fungicides are done prophylactically but insecticides are typically on an as needed basis although I’m sure there are some Neanderthals out there that just apply them as a protectant, but typically those are done only when a problem appears. And there’s a lot of debate about what level of problem you have before you act, but that’s how people do it.

So they apply miticides for controlling mites and insecticides for controlling the common insects-- which are leaf hoppers, predominantly, and occasionally sharp shooters. And sharp shooters, until they banned it, they were actually spraying---they might still be--spraying the riparian areas where the sharpshooter overwinters--with strong insecticides to prevent their migration out of the riparian area into the grapes. 

And then if they did migrate out, they’d spray the grapes themselves. 

There are also the occasional other leaf eating bug that shows up but they’re pretty rare so they don’t typically spray for those. 

Mealy bugs are the other thing that lots of people use pesticides for. There are various types. They use granular baits, for mealy bugs and they also spray on the plant, to kill the mealy bug. I think those are the only two common ones that are still being used. There were some other ones, but I think they’ve stopped using them.

Gophers are another major problem, and people use toxic rodenticides to kill gophers-- commonly strychnine, but there are also more modern things that they use that are toxic and kill gophers and/or voles and/or ground squirrels, all of which can occasionally be problems.

Oh and then there was the European Grapevine moth [until 2016, when it was eradicated], so conventional growers spray a long lasting insecticide on grape vines at least twice a season and sometimes three to kill off the grapevine moth--well actually the larva of the grapevine moth. 

What other crap are they putting out there...Insecticides, fungicides, herbicides, rodenticides...I guess that’s it on the world of sides. thinking out loud if there’s any other ridiculous things they’re still doing…

They also have a pretty low threshold for riparian diversity so they often times use herbicides in the streams and creek areas to kill off anything that might be a host for leafhopper or sharp shooter. That’s kind of common. Oh, and cutworms is another one they use insecticides for. Those are either baits or sprays. 

Occasionally white flies are an insect that shows up on certain properties in the Napa Valley and they spray for that with various kinds of long lived insecticides. 

I think that’s kind of it, off the top of my head, the most common spray and pray program going on in the Napa Valley on grapes at the moment.

Oh there is one more thing. They also foliar apply nutrients. And that really ranges with what they use. But they’re soluble, chemically derived nutrients. 

And then the people are in between that are using Roundup...oh you didn’t talk about Roundup for these guys.

Yeah, they’ll use Roundup if the soil sterilant fails or if they have a problem with summer weeds. Summer weeds typically aren’t killed off by these pre-emergents--so they’ll come in and spray around summer weeds under the vine row. If it’s significant enough weed growth. 

LIke you can’t put them all in one category, some people are religious users of pre-emergents and they also Roundup. And there are some conventional growers who just use Roundup. But I think more commonly it’s the pre-emergent approach. And then Roundup is used as sort of a catch thing--the pre-emergent missed or came up after the preemergent broke down and is no longer active.

MIDDLE GROUP

Now the group in the middle--again it’s difficult to categorize because you could probably interview a 100 growers and get a 100 answer--but my guess is that they would still not be abhorrent to using fumigants. They’re typically more likely to use Roundup instead of pre-emergents, although I’m sure some do both, but the group that likes to call themselves “sustainable” tend to be more advocates of using Roundup than of pre-emergents. 

They also commonly use the same arsenal of pesticides and fungicides, insecticides, rodenticides that conventional growers, mainstream ones, use, although there seems to be a trend toward using more of these softer fungicides some of which are approved for organic farming. 

Although again you’d get a wide range talking to clients or growers about it, because they really seem to vary, but they use fertilizers to supplement the vine growth. They spray on synthetic fertilizers as foliar nutrients. And again, you might find someone who says, “Oh no, I only use organic things. Except for Roundup.” 

I hear all kinds of things. There’s no regulation on the term green or for the word “sustainable.” So you can kind of put anything you want in that basket and, like I said earlier, if you’re in business this morning, by definition, you’re “sustainable.”. 

It’s a difficult to pin down to what exactly they do or don’t do, cause you might find some people who are really pro-active and do positive things and oh yeah, we also use Roundup. And then you’ve got a group that’s pretty much using every chemical in the book, except they stopped using soil sterilants. So they think of themselves as greener. 

I’ve been in a lot of debates over this with different growers, and it’s a losing situation to come up with what “sustainable” means. It’s just--you pick your definition. 

But if I was dividing them without really interviewing every grower, I would say a common dividing line is the nonuse of soil sterilants for weed control. And that the more common thing is to use Roundup. 

And then after that it’s just potluck about what level of greenness that farmer is into.

So the organic approach - can you walk through that cycle...

Organic is a lot more complicated because it takes longer, and it’s more pro-active and anticipatory rather than reactive. 

So starting back at the beginning: if I am going to replant a vineyard, we’re going to take that ground out of production for two years, hopefully--sometimes three--but at least two years in an opportunity to break the disease and nematode cycle. 

During that time, we are going to plant cover crops which are designed to kill off the pathogens and increase the organic matter in the soil--which stimulates the beneficial microbes. 

We are going to put compost into the soil to increase the soil biology and water holding capacity and the nutrient supply. 

We’re going to balance the fertility if there’s a particular element that’s out of whack. Around Napa, there’s excess magnesium--which limits the amount of available elements like potassium and calcium--so we would try to balance that out before putting the grape vines in. 

When the grapes are ready to be planted, we till the ground rather than spray an herbicide prior to planting. 

The holes would be dug--typically compost is added to the hole when you plant, and also a lot of growers add in mycorrhizal fungi, which is a microscopic fungi which stimulates root development and nutrient uptake. 

We plant the grapes--hopefully in adequately prepared soil with enough fertility--and then, as needed, we would supplement that fertility during the first season with either dry, organic slow release fertilizers placed under the drip emitter or liquid fertilizers--organic liquid fertilizers--that are applied maybe monthly or so during the growing season to stimulate new growth.

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Then we would cultivate the weeds around the plants, typically by hand, when they’re young. The rows would be done with tractor work, but, in the actual vines themselves, it’s typically done by hand the first couple years because there isn’t any equipment that will handle small weeds. 

As the vines get established, they get on the stake and you change over to mechanical weed control, and there’s numerous versions of equipment being used for that. 

Some growers, once the vines get established, actually plant a low-growing competitive cover underneath the vine that doesn’t require cultivation and will compete with the weeds. 

But most commonly, people cultivate. Some people graze animals--and that’s probably true with the sustainable group, too--sheep or goats--in the spring before bud break. So that’s a weed control technique. 

Then the organic growers are going to plant a cover crop in between every row when the vines are young. And then again, you might find some of that now in the conventional and sustainable growers as well. 

Those cover crops are going to be managed different ways, depending on the county’s restrictions. 

If you’re on a hillside, you can’t till them. 

If you’re on flatter ground, then typically those are tilled up for at least the first couple or three years to incorporate the organic material and the nitrogen to produce the competition against the grapevine. ???

And then perhaps depending on how vigorous the vines are, they might do some version of a non-tilled cover crop system, or some version of mowing or grazing.

Then there’s rodent control. Rodents are typically controlled mechanically by traps, or with the placing of owl boxes or hop perches to increase the amount of predators of rodents. We use traps of different kinds for the different kinds of rodents; they’re not all the same trap because there are different kinds of rodents. 

Generally speaking, once a grapevine’s established, or even after a couple years of growth, we almost never apply any extra nutrients through the water system, although occasionally, I think most organic growers do a pre-bloom foliar spray to stimulate fruit set by increasing the amount of nutrients for the flowers and their fertility so they set more. That’s pretty common. 

Then there’s a lot of preventative actions done for pest management. 

Often organic growers will plant the riparian areas with beneficial insectiary plants to increase the amount of predators and parasites that feed on the sharp shooter or the leaf hopper or the white fly or whatever bug you might be coming up against. 

There are also traps used to prevent the migration of the sharpshooter out of the riparian area--yellow sticky traps are the most common and they catch the adult before it migrates into the vineyard. 

Also we use some clay--a sprayable clay--that turns the vines white and repels those bugs early on, so they don’t come in and feed on the grapes. 

We also work on plant nutrition to make sure the plant’s not super lush and vigorous, because that attracts more problems with diseases and insects. We want a plant that’s hardy. That’s why many of these growers are also using limited irrigation, because that makes a hardier plant with less disease problems and fewer insect problems. 

Depending on what kind of bug it is, there’s a wide range of tactics that are used to control them. 

So with mealy bugs, we use everything from biological control releases to pheromone confusion to ant baits to plant derived insecticides.

For example, the European Grapevine Moth--people used a combination of pheromones, confusion, mating, and applications to kill the larva when they’re fed in the grape cluster. [It was eradicated in 2016.]

For leafhoppers, we manage the plants by nutrition--as early as possible is important. If you get super vigorous, leafhoppers do better. 

We release a wide spectrum of beneficial insects. We plant habitat--beneficial insect habitat--things that eat leafhoppers, including prune plums--some growers are still doing that. There’s a species of wasp that attacks leafhopper. 

And then if all else fails, then we’ll apply either a soap-based or a plant-derived insecticide against the mite fly, but we do that only when the populations are threatening the grape vine. Usually plants grow out of it just fine. Same thing with mites. We release predatory mites. We manage the habitat to encourage predatory mites. We plant things under the vines to keep predators around--alyssium is planted by some growers as a beneficial insectiary plant. Predatory mites. We also do monitoring so we know when the problem is developing and if there’s enough predators, we leave them alone. 

If there’s not enough predators, we do some intervention. Typically, early in the season, we use oil spray, which smothers the mite eggs and also acts as an organic mildew fungicide--kind of two things at once. 

With white flies,there are two different management techniques. One is to remove the host plant that grows in the wild around grapevines, that allows the white fly to overwinter. It’s called coffeeberry. And you’d go in and take those out--selectively, mechanically, saw it out. That reduces the amount of overwintering white fly. 

There’s a parasitoid and a predator that you release to attack the white fly, once it’s in the vineyard. And we plant habitat--plants to seed those predators and parasites--so they can multiply and eat the little bastard. 

Those are the main bugs. 

DISEASES

Diseases. That is prophylactically done. 

In grapevines, you do not wait for a problem with mildew. You prevent it by keeping the foliage from getting the mildew. 

That’s done with a mixture of oil sprays, minerals like sulfur, and biological materials which essentially flood the leaf with some other species of non pathogenic bacteria or fungi or yeast that keeps the mildew from growing. 

Then if we have a problem with mildew, we do have a couple of materials that will kill it. 

One’s based on a sodium bicarbonate, which is more like baking soda, and another is based on an oil. So depending on...that’s not a very common situation but you could get control with mildew.

We also do cultural practices to control mites, with mildew--keeping the vigor down--opening up the plant, so there’s light penetration and air penetration and excess shoots, so there are not great places for the mildew to grow. 

Bunch rot is typically dealt with on a reaction basis as opposed to prophylactically. If we see bunch rot developing, there are a couple of organic biological materials that will inhibit its growth, but normally that’s not done unless we see a problem with it. 

I think a common thing with the organic farmers is they spend more time monitoring and decision making and less time spraying. 

So you might wait it out with an organic field. In fact I commonly do. Whereas if you were farming conventionally, you would bring in the heavy duty hammer and nail it right away. 

We try to let nature take its course and see if we can get enough beneficial insects on their own to do the job, or add extra ones to build up the population, or provide a habitat so that more of the beneficials are in the neighborhood. 

But sometimes you have to do intervention. We now have reasonably good tools for doing that. 

I think that’s most of the differences.includes what they do, how long they’ve been at it, and what got them to where they are.