In the NYT article I just blogged about, there is a toxic aside:
The strength of the disease has shocked hardened farmers: topical copper sprays, a convenient organic preventive, have been much less effective than in past years.
Convenient organic preventive?
Organic farming has a few dirty secrets. This is one of the worst. For some reason, it is ok to spray inorganic copper, a toxic heavy metal, on organic crops. A farmer who cares about the environment, health, or whatever good thing organic farming stands for should not use it. Buyers of organic tomatoes in the northwest of the USA are being duped.
There may be a misunderstanding here. Copper is an essential nutrient, one of many minerals needed for life. Plants can’t use organic nutrients, they require mineralized nutrients. Organic materials must be processed by microorganisms which break them down into their mineral states before plants can use them.
Copper is also an EPA approved anti-microbial. That’s one of the reasons that copper cookware is good hygiene, and why some hospitals are changing their metal fixtures, such as door handles, from stainless steel to copper or brass plated versions. It’s more effective and less environmentally harmful than current anti-microbials used for sanitization, and may contribute less to evolved resistance.
Copper is no more “inorganic” or “unnatural” than nitrate. Yes, they are both minerals but that’s what plants eat and what microorganisms make. However, it is well to remember that it’s the dose that makes the poison. So long as they are not present in high concentrations they are food rather than poison.
Thanks for the clarification; I probably was too harsh. Organic tomato farmers probably do not spray as much as some wine producers on their grapes (I believe there is quite a bit of copper toxicity in the French terroirs, or I am wrong there too?).
But if you advocate agriculture without biocides, why then make exceptions? And if you do, are copper based products really the best choice? The alternatives such as cholorthalonil are not great either, but is the choice for copper rational?
Why are liberals illiberal? Why are conservatives often cavalier about conservation? It is well not to get too literal. The words do not define the practices and systems, it’s the other way. Organic is short hand terminology for an evolving set of practices that don’t actually hang together as a coherent agronomic system so much as a set of marketing and trade poses designed to maximize income for practitioners and exclude competition by raising the cost of entry into the market. A wide variety of agronomic systems shelter inside that tent.
I understood that the use of copper fungicides had been deprecated and (probably by now) prohibited by the Soil Association for UK based organic growers. I’m surprised that the US aren’t in accord with this.
It is a problem, there are very few methods available to the amateur organic grower to combat blight and it continues to be a serious problem for potato and tomato growers. No matter how much we’d like to avoid using it, what else can we do?
However, despite what I said about SA I can’t actually find any clear guidance by googling…
@back40. Yes, the real world is complex and evolving. The organic vs inorganic was tongue in cheek but I like the idea of organic agriculture as a big tent with evolving practices (but it is too bad that it is hard to get in). As the long as the main point is to be distinct and in some ways preferable to conventional agriculture (a much bigger tent at that) it is fine with me. Perhaps one day nitrate (applied in its inorganic form) will be used in organic farming too.
Isn’t toxicity about how much of a certain chemical substance we get into our stomachs? I don’t think copper cookware will contribute as much as copper spraying in “organic” agriculture.
Another question: How do (different) organic farmers think about micronutrient supply in mineral form?
@Catofstripes. “No matter how much we’d like to avoid using it, what else can we do?”. I can live with that. But, from my armchair, not having to worry about paying off the debt on my farm, I propose that, if, by an act of God, fungicides would no longer be available, alternative solutions would be found, sooner or later. For one, the search for and use of resistance would increase. In the short run tomatoes would get harder to grow in some places and dearer, but, perhaps, on the long run, we would figure out how to grow them without biocides. Or choose to eat something else (God forbid, they are my favorite vegetable).
@Jacob. Our stomachs, the soil, the water…. I do not use copper pots or aluminum espresso makers, I go for steel. You would perhaps make the same the argument — that there are bigger worries — for many other biocides, organic or inorganic.
I would certainly hope that big-tent-organic agriculture would be cool with micro-nutrient fertilization; but I am obviously out of touch.
Copper fungicides are also widely used in coffee production, and allowed in organic coffee. In areas with high incidence of coffee rust, Hemileia vastatrix, such as Kenya, copper fungicides are heavily used. Unfortunately, I’ve read some papers documenting over- and long-term use has contaminated soils and waterways.
I’d like to see some transgenic plants that simply resist fungal infection, but that’s not organic – even though it would reduce or eliminate the need for chemical sprays.
I’d like to see those transgenics to. And I reckon that if they would be available they would be allowed in organic farming very soon. But is it likely we will be seeing some of that any time soon? Has anyone made a crop immune to oomycetes (or fungi) with transgenics?
Actually, yeah, there has been work on making transgenic plants that are resistant to fungi. You could just do a google search, or check out this one involving bananas. I don’t know of any that are far along in development, though.
I know there is a lot of work being done. I just have not heard of a real breakthrough, i.e., a transgenic disease resistant crop that could not have (or not easily) been developed with classical breeding. Plenty of interesting research (and optimistic press releases and bloggers), but is there anything big out there that works in the field? I just have not heard of it; which says little. But I am curious. Is Bt-corn going to be the rule or the exception? (And does Bt-corn still work as good as it did?)
This is getting a little off topic, but I think Bt is going to be tough to beat as far as an effective transgene that works in a variety of situations. The yield gained with Bt will be tough to beat as well. I really wonder if the success of Bt isn’t a main reason why we haven’t seen more transgenes being developed. In other words, the return on investment for Bt has been pretty good – it’s proven to work. Why should a company risk spending a ton of money on R&D for something that might not pay as well? There needs to be more public funding for more risky projects.
As for what GM fungal resistance is possible above and beyond what can be done with breeding, see the review PDF Fungus Resistant Transgenic Plants: Strategies, Progress and Lessons Learnt from the Bangladesh Association for Plant Tissue Culture & Biotechnology. Some options not possible with breeding include expressing chitinase that breaks down the cell walls of fungi and RNAi.
You beat me to the punch on mentioning chitinase (to destroy fungal cell walls) as a tool that transgenics can use and breeding cannot!
I don’t think that transgenics vs. breeding is an either-or. Not even the big seed companies believe that. They spend tons of money breeding for beneficial traits, and then tack on a few transgenes to seal the deal. One could take monogenic fungus-resistant potatoes, for instance, and add chitinase or some other transgene to make it a polygenic resistant plant. Pyramiding/stacking isn’t just for transgenes!
I wanted to know whether there is anything big happening, or about to happen, in farmer’s fields. The article that Anastasia cites suggests “not really”: Not much progress has been in made toward fungus resistant transgenic crops. There were only a few reports on field evaluation and commercialisation. One of the reasons for this is the inadequate level of resistance found. Getting transgenes for durable is another challenge.
The article is from 2006, perhaps that is ancient history in this field?
Robert, sorry for the age of the article – it was the best review I could find. 2006 isn’t that old, though, even in a fast moving field. I poked around a bit more and found the 2006 Overexpression of defense response genes in transgenic wheat enhances resistance to Fusarium head blight (neat because it uses cisgenes from wheat or wheat relatives) and the 2008 Antibody-mediated Prevention of Fusarium Mycotoxins in the Field (neat because it solves a problem that, according to the authors, hasn’t been solvable with breeding). Note that neither of these is happening in the US and neither was funded by corporations.
What does transgenics have to do with this?
Public domain plant breeder Tom Wagner has created quite a number of potato lines totally resistant to late blight.
It’s true not a lot has been achieved with traditional breeding of tomatoes for late blight, but people are working on it and solutions will be found. There are a few options available however. Certainly if larger seed companies saw this as a good place for investment, quite a lot could be accomplished in a short time.
Quite aside for the usual debate of if GMOs are good or bad, traditional breeding can accomplish good things too. Indeed, if large seed companies and food producers wanted to use and invest in blight resistant varieties, there’s a lot available right now, it’s just not being used.
Full circle: conventional breeding is what Dan Barber suggested we needed more of — and that has been said on this blog before. It is too bad that modern breeding is associated with loss of quality (e.g. “Los tomates saben a nada” in today’s El Pais).
It obviously does not have to be that way. If there is demand for a diverse set if resistant and tasty varieties, and “there’s a lot available” why don’t breeders and seed companies supply? No demand? Too expensive? All in cahoots with Big Chemicals?
“Tom Wagner has created quite a number of potato lines totally resistant to late blight.”
That would be spectacular; it is one of the worst crop diseases. Several breeding programs worldwide have tried for decades, but not been able to get that.
Any evidence? Particularly of how wide and long these lines were tested? And of how this wonderful feat was achieved.
I Googled Tom Wagner, found his interesting looking blog, and some places where they also made this statement; but no elaboration.
There definitely is genetic variation in late blight resistance. There is also immunity (total resistance) with “R” genes that are easily overcome by the pathogen and therefore does not last long in the field. What is it that Tom has?
Two comments.
1. I happened to come across this recent article which gives an interesting update on potato breeding and late blight. Since the article is in Dutch, here’s a quick summary.
Varieties with monogenic resistance are now available (Bionica, Toluca), but cultivating these varieties could lead to resistance breakdown. However, the article says we should be patient and go for polygenic resistance. Varieties with several resistance genes in different combinations would be far more difficult to beat. This would decrease the worth of the individual genes, before they can be “stacked”. Biotechnology would speed up the required stacking of genes for durable resistance.
I guess those varieties could avoid a lot of “organic” copper spraying…
2. Commercial sector tomato breeding has focused on taste characteristics since the 1990s. “Los tomates ya no saben a nada,” means, I guess, there is still little market differentiation according to taste in the Spanish/European market?
I have had more and less tasty Spanish tomatoes this summer. The thing is that you can’t “see” taste when you buy (the variety is not indicated).
Combining R genes has failed in the past. But perhaps there weren’t enough genes involved? With the assistance of molecular markers it should now be easier to stack them, in conventional breeding.
But I suspect that it would take more than that; that you would have to have several complex sets of resistance genes that turn-over in time and space. Imagine a seed system producing varieties that have a different set of resistance genes every year. Should be doable with biotech (if you wanted the varieties to stay the same in other respects). But it would take organization, legislation.
Famous spudman John Niederhouser proposed a system like that. He called it RETONA: Return To Nature.
Tom’s blog entry of August 18 explains his late blight resistance work.
Tom’s entry on the 18th concerns tomatoes.
In a much more rigorous way, he basically says what I did below on multi-gene resistance. It’s just not that simple.
I don’t know the details of the resistance Tom has, but I do know he’s been working with it in his fields in Washington state for a few years now.
On the subject of horizontal/multi-gene resistance, I would say I have my doubts. For over a decade now, this has been a popular approach with tomatoes. While blight resistant plants can be created this way, they never produce any tomatoes of any value. As soon as these plants are worked on to the point where they start producing interesting tomatoes, the blight resistance vanishes.
I think approaching the problem expecting horizontal resistance to be the answer is too simplistic. I suspect this is probably true for potatoes as well as tomatoes.
The Dutch article says that stacking genes is a question of time and biotechnology and that it does occur in wild species.
I would like to know what exactly causes the disappearance of resistance when genes are combined, and why some breeders still seem hopeful about polygenic resistance, even to the extent of discouraging the cultivation of monogenically resistant varieties.
I’m not sure I like threaded commenting in posts… It sure causes the discussions to go in different directions!
Anyway, I think if someone could find the answer to you question, they would make a fortune. Unfortunately, no one has figured it out yet.
Being the kind of person I am, I think the root of the problem lies with issues of biodiversity. Instead of trying to create the ultimate multi-gene resistant tomato, the answer is three-fold.
First global warming, changing weather patters and general climate degradation all play major roles in plant diseases. I think we need to address this, and recognize it’s one of the most important underlying problems behind this and many other plant diseases.
Secondly, large mono-culture swaths of diseased potatoes grown without proper rotations appear to be the major hosts of late blight. If we deal with this, we will have considerably less of a problem.
Finally, late blight is not a single plant disease. It’s a very regional problem, resistant plants in the US are not necessarily resistant in Europe, and so on. It’s also a very rapidly evolving disease, and now that different strains appear able to combine it’s DNA (sexual reproduction), it looks set to be even faster evolving. It’s just not going to happen that we find a single totally resistant variety, a solution is only going to come by being able to rapidly produce new varieties on a regional basis. This probably has to come down to the level of individual gardens, and people will need to know how to breed and select their own varieties.
I think this all applies to both tomatoes and potatoes, as well as many other plants.
I didn’t mean to imply that fungus resistant lines couldn’t be developed with breeding. However, if there are lines that work, then why aren’t they used? If they work, then surely farmers would demand and seed companies would supply. Or maybe they are used and I just don’t know about it? Does anyone know of resources that chart what varieties are used for common crops? For example, how many different varieties of tomatoes are planted in what ratios in different regions of the US? I’m curious from a foodie standpoint, and also for reasons of biodiversity, etc.
Thanks for all your comments Anastasia (and for following me into the off-topic). I agree that more info about patterns of varietal use, turn-over, needs, etc. would be very useful.
“However, if there are lines that work, then why aren’t they used? If they work, then surely farmers would demand and seed companies would supply. Or maybe they are used and I just don’t know about it?”
I’m not in a position to say much about how they are currently used, but I can certainly offer some of the reasons why seed companies are not interested in offering them.
Since most seed companies sell both chemicals and seeds, their business model is very much tied to selling these two things together. There is simply less profit is selling varieties that don’t need chemicals. There are sometimes direct or indirect subsidies that offset the costs of these chemicals, meaning farmers often don’t mind using them.
There are different ways in different places seed companies can use to protect their intellectual property, and these methods often aren’t available for existing or order varieties, rather they would need to create something new. In addition, many existing varieties are not suitable for commercial production, would require investments in time and money and for whatever reason they may not think this is worthwhile. Perhaps they are looking at the situation financially now, doing the calculation of the costs of investments and not expecting to see an increase in profit if they did something else.
I don’t know about in the US, but here in Europe, farmers are not generally in a position to demand varieties. Mostly it’s the seed companies that create varieties, and the farmers have to buy them. I suspect this is the case in many places in the world.
“Since most seed companies sell both chemicals and seeds, their business model is very much tied to selling these two things together. There is simply less profit is selling varieties that don’t need chemicals.”
I would like to point out that some of these chemicals, such as insecticides, are being actively undermined by some of their genetic engineering projects. Indeed, I sat in on a presentation by someone from Pioneer Hi-Bred, in which they pointed out that they sell an insecticide for rootworm beetles (I think this was the one), and also developed a rootworm-resistant transgenic, thereby undercutting their sales of the insecticide.
Why would they cut off a revenue stream like this? It seems counterintuitive by your reasoning above. But it makes a lot of sense if you think about the competition between companies that are generating these traits. If Monsanto develops a rootworm-resistant transgenic, (as they have) then their seed sales will undercut Pioneer’s insecticide sales. So it is in Pioneer’s business interests to undercut their own insectide with their own transgenic plants before Monsanto does it first. That’s the motivation. Moreover, if the seed companies can make money off of selling seeds that reduce farmer’s costs (fewer sprayings of herbicide, pesticide, fungicide, fertilizer, etc) then they have a financial motivation to generate crops that reduce or eliminate these farm inputs.
Hi Karl,
I think you’re probably right, there is competition in the way you say.
While health care is being debated in the US, and the issue of a need for a public or non-profit insurer to compete with the existing health insurance companies, it makes me wonder if we need something like that for the seed companies. There are so few seed companies by now supplying mainstream farmers, and I don’t really see a lot of genuine competition between them.
This seems a good article on copper in organic agriculture (tomato and potato).
http://www.extension.org/article/18351
Thanks Jacob, for bringing us back to the subject at hand, and for the good article. Pretty toxic it is, copper. How unfortunate that the spray trial at Oregon State found it to be more effective than composted tea leaves.
I think horizontal resistance (polygenic resistance) was/is at the heart of the work of plant breeder and pathologist Raoul Robinson’s work with potatoes. He and others have also used mass selection to produce lines of disease resistant beans in Mexico. His ebook is available here: http://www.sharebooks.ca/eBooks/ReturnToResistance.pdf. He discusses vertical and horizontal resistance and proposes setting up plant breeding clubs – affiliations of academics, farmers and “resolute amateurs” who grow and evaluate plants from recurrent mass selection breeding programmes. Sounds like fun.
A farmers’ breeding club has been organized to improve taro in Samoa. Seems to be working too.
And that breeding club and programme was based on Raoul’s ideas which are covered in detail in the Return to Resistance book mentioned above.
And so it comes full circle.