David M. Stark, NatureMark, Monsanto, Chesterfield, USA
Thanks for having me come here to share what it is we're doing. Let me start by saying Monsanto is not an entity that sits someplace in Missouri. It really is just a bunch of people that work together in a common area. So when you say, Monsanto says this or Monsanto does that, that's not really true. It's people and that's why I'm here. And it's hard for me to understand what it is you're really thinking when I'm sitting in my office in St. Louis. So I really do want to know what's on your mind what your concerns are. Then lets talk them through and find out what we need to change and also help you understand what it is we've really done.
We're actually very proud of the products that we're making from genetic engineering. We think that it's really the breakthrough we need in agriculture. If we look at the need in terms of changing how food is grown, even in places like the USA and Western Europe where there's not a food shortage, where agriculture the way it's done today does feed us and food is very affordable. But then we look at places like the Gulf of Mexico, where one third of the USA run-off water enters into the Mississippi River and then that goes into the Gulf, down by New Orleans and Louisiana. We see huge dead zones in the Gulf because of the alga blooms. It's basically ruining the shrimp and fishing industry, because of the way we produce food, because of all the nitrogen runoff. We look at agriculture and we participated in the agriculture industry for a number of years, but it's just not sustainable, especially when you think that every month the world adds the population of New York City, every year we add the population of Mexico, every decade we add the population of China. I have a six week old daughter at home. By the time she's my age the world population's going to be doubled. It's not going to double in Switzerland. It's not going to double in the USA. But the point is, the way we produce food, the way we produce raw materials for industrial use that are not renewable, is just not sustainable and we have to change the way we do things. By the way, no one should believe that biotechnology is the solution. It will be one tool that will lead to a solution. But we have to move forward. I'm glad I was born when I was, because I'd hate to be born when my daughter is. The world will be very different if we don't change and that's just a fact.
I want to go through some of the thought processes that we take when we want to launch a product that is genetically engineered in agriculture. And we'll use as a case study Monsanto's first transgenic crop plant and its what we call the New Leaf Potato. NatureMark is the business that I run for Monsanto. It's the potato business, but it's part of Monsanto. The NewLeaf potato is a trade mark that we use for the potato that expresses a Bt protein that provides year-long resistance to Colorado potato beetle. So I'll tell you a little bit about this product, why we think it's a great product and then go through briefly what we did in terms of safety assessment. We also have a couple of people in the audience from Monsanto's regulatory affairs area and they can certainly help me answer the questions as well.
Now in the Spring, we will launch two new crops: we call them NewLeaf Plus and NewLeaf Y. They combine the Colorado potato beetle resistance we have today with resistance to either potato leaf roll virus and that's NewLeaf Plus or potato virus Y which is NewLeaf Y. And I'd like to share our experiences in terms of why these are good products, why they're safe, how they respond in the environment, really to open the dialogue to what we saw earlier, which I believe are of course valid results. But how does all this fit in with how we're going to release and handle transgenic plants which have viral derived transgenes to give high levels of resistance to these plant viruses.
Download 86kb image: "NewLeaf Plus 1998 Commercialisation"
NewLeaf Potato - this is the Colorado potato beetle. It didn't develop in the state of Colorado that's a name for the colour by the way. It isthe number one insect pest on potato in the world. It's unfortunate that you don't have a lot of them here in Switzerland because we then can't sell potatoes here to growers. But it is a huge problem in North America and an even bigger problem in central and eastern Europe. If left unchecked the beetle can actually totally decimate the crop. And the beetle, like a lot of insects, does adapt to the environment and it also adapts to different insecticides, so the tools available to a grower to control the beetle are limited. Or we can do like they do on the Dacha plots in Russia and spend our weekends pulling off up to 200 larvae per plant and squashing them by hand. You have to control this insect. Potato leaves are like ice cream to them - they just love it. Also tomato, eggplants, so they eat more than just potatoes.
They're controlled either by the big boom irrigation systems mixing insecticides in. There are some insecticides that you can plant with the seed, but they don't last the whole season. The common way to apply insecticides to a potato crop is broadcast by airplane. What you don't see on this slide when you talk to the potato grower standing here is that over here is his house with his kids playing in the yard. These are organophosphate insecticides which even our own government's Environmental Protection Agency (EPA) has said, hey this is too much - we have to cut back the use of this especially on potato, because they are toxic. So growers are looking for an alternative to using airplanes to spray chemicals all over to get a good crop.
This is an alternative that's been in commercial use in different plants since the early 1960's. We all know about Bt I assume. It's a common soil bacterium - Bacillus thuringiensis - and it makes high levels of a certain protein. They are really amazing - God's perfect insecticide - because they are highly toxic, but extremely specific for certain insects. So the Bt protein that we took from this particular strain from the soil kills Colorado potato beetle. It doesn't even kill other coleopteran insects, with a few exceptions. With other insects, earthworms, birds, mice etc it has absolutely no activity whatsoever. So it is extremely specific, extremely toxic only to certain insects. So when we take the gene out of bacteria and put it in the potato plant, we get basically complete control of the beetle. They have to take a bite, and when they take a bite they stop feeding and basically starve to death. The point is using Bt in the potato replaces insecticides. (Slide illustrating regular potatoes that were not sprayed with an insecticide showing what damage the beetles will do and the Bt potato - NewLeaf - with absolutely no damage at all)
On average across North America when a grower uses NewLeaf potato, they reduce insecticide use by 42%. Beetles are not the only thing, at least in North America, that a grower has to spray for. The other common insect problem is the green peach aphid. It transmits potato virus Y, potato leaf roll virus and some of the other viruses. So they have to spray to control the aphids. Also in certain states like Wisconsin and Minnesota there are certain leaf hoppers that have to be sprayed for as well. Our gene doesn't control any of them it only controls Colorado potato beetle. But what happens, because the grower doesn't use these systemic insecticides early in the season, in a normal potato field that's treated with a normal regimen of insecticides, it's basically sterile. You can walk the field. We've done it with growers. You don't find anything alive, but the potato plants. You go in a NewLeaf field that has not been sprayed with insecticides and what you find there is that the predatory population of insects thrives, so spiders, ladybugs (ladybirds), praying mantis and assassin bugs can now survive. What they do is they help control the other insect pests, like the green peach aphid. So depending on where the grower is and what the natural insect pressure is for his location, they can actually reduce sprays or in some cases even eliminate sprays for the other insects, because now the predatory insect population can survive and control them. So you get a more natural situation.
What growers have also found is that they get a better crop. They get actually about $230 more an acre when they grow NewLeaf versus a regularpotato. This is because it's a better potato. It yields better, it has better size, the growers get paid for a certain size of potato that people want to eat and it also makes good French fries and potato chips. And the potato also stores better. It is more dormant enabling growers to get away from using sprout inhibitors, which in places like Japan and UK - and really all over the world once we get an alternative - are becoming banned because they are known carcinogens. So it's a better potato and they get a better crop by using the transgene.
Potato is people-food - obviously. Corn, at least in the US, is basically grown as animal food. Soya bean is a food ingredient and basically that's what corn is too. When you eat a potato, you know it. So, as a company in North America, our public acceptance issues with potato were a lot different than they were for corn and soya. And it was because of the quick service restaurants like McDonalds, Burger King and Wendy's. McDonalds sells 5 billion dollars of French fries a year. We process into French fries, 20 billion pounds of potatoes a year in North America. So its a huge deal and its a big industry - 28 billion dollars of retail. We needed to show people like McDonalds, and people in the grocery stores that now have potatoes, that their stores are not going to be burned down or picketed when people get word that they're eating these genetically modified potatoes. So what we did was we basically told people, like Zeneca did with their California puree. We labelled it 'genetically modified food' and on the back of the bag we put the story. These potatoes have a gene that enables them naturally to protect themselves against the most damaging insect pest in potato. So instead of using tractors and fuel and labour etc you can use sunlight, water and fresh air. And when we told people the story we actually outsold the competitor set three to one. And we could charge more. So that's how people react once you communicate what it is you're doing. We had basically no negative response. Now I'm not saying that we're going to launch a potato and charge more for it. That wasn't the objective. The objective was to make the potato industry comfortable with the idea of having the genetically modified potato in their system and it's worked. That's what I'd love to do here.
Actually the best environmental story we have on all our products is on Roundup-ready soya bean. But we've done a bad job of actually communicating why it's such a great product for the environment - at least if you're a soya bean grower in Iowa or Illinois and if that's also important to people here. It's certainly important to them because they're drinking atrazine in their drinking water. They're losing three tons of top soil a year because of tillage and eight hundred pounds of carbon. One third of their nitrogen goes into the water. All of that is saved by using no-till Roundup-ready soya. Its a huge environmental story.
You probably know Idaho as the potato state. It's actually called the Gem state. There they grow the most potatoes of any state in North America. The people at the University of Idaho know far more about potatoes than certainly I do. They looked at NewLeaf potato and did an environmental impact study. Now this was only looking at the input used to control Colorado potato beetle, so its not looking at everything else. I know there are a lot of different ways of looking at this story, but - just in terms of using a genetically engineered potato to control Colorado potato beetle - already we see that basically it takes sunlight, water and fresh air to produce a crop. And we've already documented that you produce a better more valuable crop for the grower. The alternative with the usual spraying insecticide method involves 2,700,000 pounds of raw material, 1,200 barrels of oil for energy, 3,000,000 pounds of formulated products. It creates 1,600,000 pounds of manufacturing waste. It's shipped in 116,000 containers. It uses 27,000 gallons of fuel to distribute and apply. And after all that, less than 5% actually kills the bug. The rest goes into the air, water and soil. So when we present this, growers and consumers have a choice. We don't force anyone to use one or the other, but for growers it's an easy choice. They know what saves them time and lets them manage the crop ina way that's better. And it is safer for the land that they live on. So that's the story of NewLeaf potato.
How do we know this product is really safe - safe for people to eat and safe for the environment? This is a very brief outline of the very thorough safety assessment thinking that went into this product before it was released. It really focused on two big areas: one is safety of the newly expressed proteins and these express a Bt gene, and a marker that confers resistance to kanamycin. Again that's no surprise as it's something that's been approved in a number of different products. So what we looked at is allergenicity and to me that's really important to focus on. You've all probably heard of the company that tried to improve the nutritional content of corn and what they did is they took a protein from Brazil nuts which is methionine rich and they expressed that in corn and it worked. It made a more nutritious corn. The problem is people who are allergic to Brazil nut now would be allergic to the corn. So what they could have done is launch their corn and keep it separate and labelled, which they'd have to do as it is absolutely the right thing to do. But instead they just dropped the product and I can tell you we would too. We don't want any unexpected allergic reactions coming up. We too have dropped projects, because of a hint that maybe what we're making is an allergen. We look at this very seriously and I think it's very important.
We also look at the environmental fate of the proteins, for example what happens when the plant outcrosses, what happens when the leaves fall into the soil, does it kill earthworms etc? So we did a very thorough study there. Metabolic fate - what happens when it's ingested - not just by people but by insects and other beneficials that actually live off the potato leaves in the field. We've found it's quickly digested and of course we did rodent feeding studies to make sure that the protein has no surprising toxic effects. And then we spent a lot of time on the compositional nutritional properties of the potato to make sure that it is as nutritious as the one that doesn't have the transgene. In case you didn't know, potato is actually extremely nutritious. It has more vitamin C than oranges, more potassium than banana. It's a great source of complex carbohydrates, has a pretty balanced protein content. Potato is an important food crop. We obtained of course a thorough understanding of the introduced DNA and looked at nutrient composition and proximate analysis by measuring protein, fat, fibre, carbohydrate, vitamins, minerals and natural toxicants.
I hope this doesn't surprise anybody. You hear people talk about pesticide residues and transgenes, but the stuff that's in the plant that it makes to defend itself so that it can survive in the environment can be pretty toxic too. In a lot of cases these toxins can be present in high levels and they can present even bigger problem. So we check them. And we also, of course, check the plant's environmental safety which involves a lot of what we heard this morning in terms of effects on outcrossing etc. What I want to point out is every value I show here, except for the level of natural toxicants, is unique to the process of testing in genetic engineering. So a potato breeder in the Netherlands who finds a wild species of potato somewhere in the Andes that has a disease resistant trait will cross thousands of genes together and will eventually come up with a new commercial cultivar. The only thing he is checking is the natural toxicants. All these other things they don't check. The breeder's potato may not even have the same nutritional composition. Testing it is not required. And we heard earlier how that could cause problems. But you know we've been breeding plants it for 8,000 years and I'd say I'm sure there are examples where that has caused problems, but for the most part we've been okay. We've improved productivity. So I'm not sure that there really needs to be all of this analysis. Maybe they need to do some. The point is this: by orders and orders of magnitude this is the most thoroughly studied potato in history - by far.
We have checked to see if the protein or proteins that we're introducing into the plant are allergens. The first question is: is thesource of the gene, like Brazil nut, a known allergen? If so, is the protein that we've planned on expressing an allergen? I've already mentioned the importance of making sure that things are not going to cause an unexpected allergic reaction. We go through a lot of tests to ensure this. When I tell the teams to check whether a product is an allergen or not, the project is dead until they show me all the data. This is important because, unless it is safe, I am not going to take it home to my kids. I'll eat it first before you ever will! So its important. But I think it's something that we can monitor and I don't want to scare. I think that we have learned a lot and there are a number of criteria and we take it seriously.
I'm sure most people here are familiar with the Bt genes and the kanamycin selectable marker in terms of their safety, how they've been used, mode of action etc. This is an acute gavage study in mice, where we gave them massive doses of Bt. You would have to eat the equivalent of 170,000 kg of the transgenic potato in a day to equal the dosage we were giving the mice. There was moderate weight gain and actually we have a lot more data besides. The bottom line is that there's no difference. The mice don't perform worse when they're fed a high diet of Bt or NPT II protein. It's a nutritious protein we know its broken down within fifteen to thirty seconds in the stomach and in the intestine and its like every other protein they eat. Its nutritional to everything but a Colorado potato beetle.
The compositional analyses show that these potatoes are no different from the normal potatoes of these varieties that we've been breeding before and match ranges given in the literature. The different transgenic lines are always identical: protein, fats, fibre, ash, carbohydrates, micronutrients, folic acid etc. Potato is a great source of folic acid and a major vitamin, vitamin C.
The expressed proteins do not cause environmental safety concern. This is not just judged by us - and you'll never believe me that we are the hardest critics in terms of what is safe - but it has also been judged by three different US agencies, by the Government of Canada, by the Government of Mexico, the Government of Japan. Japan is a rigorous one even by US standards. NewLeaf Plus Burbank potatoes are compositionally and nutritionally equivalent to the variety that we derive them from.
(The presentation was interrupted here with a question): The Japanese and Mexican submission packages are basically the same with all this data that went through the review of all their different regulatory agencies. I am sure that these were reviewed in these countries by academic experts connected with Japan's own Ministry of Health and Welfare and similarly in other countries such as Canada and so on. Keith Reding here knows more about the actual review process in Japan and Canada and so on. I do not think there is any data on this which we would not share.
Okay I'm going to change gear unless there's a question on NewLeaf potato and the process it goes through. This is really abbreviated, this work actually took years of study to get through.
(Question as to natural status of Bt toxin): It is not true at all that the toxin is of a different structure in our transgenics. We actually went through a very thorough analysis called 'equivalence' to make sure that what we were expressing in the plant was equivalent to what's in nature. So it's nature identical. It is the same toxin. We did not isolate enough protein from the potatoes to do crystallographic protein structural analysis - how it folds in the plant etc. We know it has similar bioactivity though.
(Comment from Johannes Wirz that Guenther Stotzky pointed out that Bt toxin in plants is already in soluble form, whereas the natural toxin is in prototoxin crystalline form.) That's probably true in the bacteria. I don't know what they do when they formulate it, but you're right, I cannot say whether they form crystals in the potato or not. I think we've looked at it, but I honestly don't know the result. Differentfirms own different forms of Bt, some truncated, others, like us and Mycogen, claim they own full length Bt toxin genes. Certain truncated Bt genes do have a good efficacy. I cannot say that what I said for potato is true for all Bt crops.
(Responding to a comment from Barbara Weber as to the interpretation of 'equivalence' vis a vis statistically significant differences in Monsanto transgenic soya beans being classed as 'equivalent' in studies where no ranges for non-transgenics were given.) There are published literature ranges for components. Soya bean compositions vary from field to field, especially with oil content where colder climates induce more unsaturated fats. We have to be within a known range and that is what they define as 'equivalent'. If the ranges are omitted, that is a mistake and I am surprised to hear it. You should be able to look at it and come to your own conclusion.
(Question about the claim that the NewLeaf Plus is better than the non-transgenic potato.) Potatoes are produced vegetatively and do not go through a true seed cycle in commercial production. Clonally selecting them has gone on as long as we have been growing them. The Russet Burbank variety, predominant in north America, that is now grown is much better than the one grown 20 years ago - just by line selection. A potato is genetically very heterogeneous. Whatever the changes that naturally take place, we were able to select a clonal line of Russet Burbank that actually performs better than its parents. That is typical in potato. This is nothing to do with the Bt transgene.
(If, as you said, the Colorado beetle adapts very quickly to pesticides. How long you think it will take to adapt to the Bt protein?) A great question! Nowhere in the history of crop protection chemistry introduction has a resistance management plan been attached to the crop protection chemistry. This is the first time. In the potato we do not have to do any resistance management that is mandated by the government. But we proposed our own plan anyhow. We want Bt to have a long life. We are limiting growers to how much they can plant. They have to rotate crops. In other words they have to use smart farm practice. Nothing will substitute for this in terms of productivity and feeding the world. At the same time we have a library of 10,000 different Bacillus thuringiensis strains, all with a different Bt. We can put in different Bts so that the insect would have to have two very different mutations in order to overcome them. We also have non-Bt insecticidal proteins that we are putting in. So we are going to build a resistance management to make sure that the product has a very long life.
(Keith Reding added here that Bt sprays do not have any resistance management regulatory requirement and Klaus Ammann mentioned the use of refuges.) Yes - with the sprays - that is where you get resistance. But others would argue that the risk of Bt resistance development is less with the transgene, because there is complete control. I am not an expert and cannot argue your side, but I tell you what I hear. If you apply Bt as a foliar spray its protein is inactivated by sunlight. The new growth will not be protected and water will wash it off. So it is a situation where the insect and the insecticidal agent can coexist. And that would encourage the resistance to develop. In a Bt transgenic potato field there are none of those insects and the lethal dose is way high. Again, this is the argument I hear from certain people in academia who say that the resistance risk is lower using the transgenic. Only time will tell who is right. I want to make sure that we have a product which lasts a long time.
(Klaus Ammann: There are closed system experiments showing that after about 70 generations a 50% resistance develops.) In terms of beetles they are much less fit than the wild type beetle. They would not survive. I do not want to minimise the risk of this. We are very aware of it. We also work hard to avoid putting in antibiotic resistance markers into our transgenics, other than kanamycin that is generally accepted. We are also very interested in new marker technology. One of the best markers is resistance to Roundup herbicide.
(A question on labelling) There is a huge distinction between keepingthe crop separate and labelled - for which there is no requirement by law - and what we did. What we did is to brand the potatoes. We contracted with certain growers and packers to keep part of the crop separate and we put it in a bag and put a brand name on the product. But that is not to say that the potatoes in the bag next to it did not have some NewLeaf in them as well. It's a big difference. We are exploring the branding idea. When you communicate the benefit of biotechnology it is a very positive point for differentiation with the consumer. We are looking hard at that. We have to be very up front and honest in terms of what we have done. The reaction of people to the potato was: wow! this is good for the environment, it's good for my family - and they take it home. They vote with their pocket book. What the questioner is saying is that we should launch a branded line of produce that says that this gene modified and we're looking at that. It is very expensive and complicated from an execution and business point of view, but we agree with what the questioner is saying. There is a lot of benefit in branding, but this is very different from the government mandating that you have to keep the product separate and label it. We know from experience from growers that when they have to keep it separate, they cannot take it to people who make French fries for MacDonalds, even though it has all these benefits, they tend not to grow it. So what you get instead, because of mandatory segregation, is what the EPA calls a full risk cup of organophosphate insecticides. That is our experience.
(Klaus Ammann, responding to a questioner's concern that these products, compared to pesticides, are introducing a completely new risk: the current policy involves 'substantial equivalence'. In the next few years I think there will be labelling of transgenic products. There is the matter of allergy. In Switzerland we are not required to label soya. But if all soya is transgenic it will be labelled anyway. That's new for the consumers. There are six allergens in it. The USA is much more pragmatic as regards the real threats and risks.) Even if it weren't substantially equivalent then even in the USA, by law, it would have to be labelled. There is a labelling law but it is based on equivalence.
(Barbara Weber pointed out that potatoes are eaten throughout a person's life and therefore the safety tests should be for a much longer period. Keith Reding responded that the studies lasted 28 days.) The duration is because we are told by experts working in toxicology that proteins will have acute, not chronic, toxicity.
(Klaus Ammann said that he was informed by a top immunologist that allergies cannot be built up. It is all or nothing. Antibodies build up very quickly. Peanut allergy is very dangerous, but rare.
(Keith Reding asked Barbara Weber how she would propose to test for product effects when it is eaten and no longer potato. We would not be testing for protein any more.)
(David Stark resumed his presentation) Now I will move on to virus resistance in plants. From this comparison of normal and transgenic potato plants that have been inoculated with potato virus Y it is clear how seriously PVY can damage the crop, especially with secondary infection. So what of the advantages of putting in virus resistance through genetic engineering? The main one is that it provides superior resistance to the virus compared to the methods of control that are used today. It works out in the field because the plants wont even carry a low level of infection. It gives complete control. It improves overall crop quality and value and again it's safe, it's using a piece of the virus itself. So as long as we've been eating plants we've been eating viral genes and viral proteins. The level that's in the transgenic plant is usually 100 to 200 fold lower than what's in the naturally infected plant. I remember back in graduate school when we put the tomato mosaic virus coat protein gene in the tomato. This was the first field trial to my knowledge of any genetically engineered plant. We went to the grocery store around the corner and we measured virus levels and we measured the coat protein in the transgene. It turned out that we needed to eat 10,000 transgenic tomatoes to get the same level of coat protein in onetomato we got at the grocery store from natural infections. So we took the coat protein gene. We used the O strain instead of the N strain. They're both common strains. O is predominant in north America, but there are tuber necrosis strains there too. We made these plants which were highly resistant to O and we sent them - because we wanted to understand how broad the resistance was against different viruses - to Rudra Singh at Agriculture and Agri-food Canada. He's one of the more renowned virologists in North America probably the leading potyvirus expert. And Rudra really challenged these plants by mechanical inoculation, aphid inoculation and he even did some grafting. So he really tried to infect them. By the way over two different growing seasons he used the O strain, two different tuber necrosis strains, one from California, one from Slovenia and he used potato virus A which is a more distantly related potyvirus. So it's in the same family of viruses. It's not a strain of PVY. It's a totally different potyvirus and PVA is another common problem in potato. And then he checked plants after they were inoculated. He also looked for secondary infections from tuber sprouts with sensitive tests including ELISA and PCR. So he was looking for the actual viral genetic information.
The bottom line is expression of the PVY O protein gives complete control of the O strain and the two different N strains of PVY. It does not control PVA. It does not control viruses that are not in the potyvirus family. The plants will react normally to these viruses. There is nothing unexpected. And he said - this is now in the new jargon - it was extreme resistance. By the way Shepody has natural resistance to PVA. That's why it shows zero infection. What he didn't do was co-inoculations which I wish he had. So, these plants have now been in the field undergoing seed bulk-up. A potato, because it's vegetatively propagated, takes four field growing seasons to get enough seed before you sell the tubers to a commercial grower. And because they're vegetatively propagated they carry a lot of diseases. And as we saw earlier that if you get viral disease, especially, in the tuber, and replant them, you have a serious problem in terms of productivity. So people in Western Europe and North America and other places only grow what's called certified seed. The certification process that all potatoes go through is designed to eliminate viral diseases and also other diseases from the seed system. They don't go through a true seed which is a cleansing process for things like corn and wheat. Potato doesn't have that advantage. So this is a regulatory process that's administered by the government and its a requirement. Growers have to submit a full history of where their seed came from, the different certification numbers and they provide 200 - 400 tubers per lot to the certification agency. The certification agency inspects the field throughout the growing season. They test plants which come down with what look like viral diseases, inspect storage facilities and shipping points. They'll also conduct post harvest trials. Some of these potatoes will then go to Florida for the winter and they'll be planted back and they'll look for secondary infection, because that's the real acid test for whether there was a virus in the potato. They'll test these sprouts by ELISA for the presence and the identity of a particular virus and then after going through all this, they will certify seed lots if they are free of virus and other diseases and they also make sure that they're varietally pure to ensure it's really Russet Burbank and not Shepody that you're buying for example. Some varieties in terms of seed are more expensive than another. So this is a very rigid system again for monitoring and eliminating viral diseases. This has been going on for more than 80 years at least in North America. What we've learned from this observing viruses in potato for over 80 years is that the virus and the viral diseases are stable. They're stable in their host range and their symptom expression. There aren't a whole lot of strains and the strains are stable. They're vectored by the same insect over 80 years. They have the same impact on productivity and quality and - where there are natural resistance genes - they don't tend to overcome those resistance genes they tend to be durable in a given variety. So theconclusion is that during this 80 year plus history frequently there are multiple viruses in the same plant - that is a common occurrence in a potato field. So your experiments (addressing Pia Malnoë) are very important and valid - mixed infections are common. But in the potato field there's really little change in the virus or the attribute by which the certification agency identifies it. In other words PVY O is the same PVY O that was identified back in 1932. So they're stable and they aren't undergoing a lot of recombination. Recombination occurs but the recombinants obviously don't take over. So that's what we know from certification.
The point of this is we cannot say what's going to happen. We know we have complete resistance. What we saw earlier is that there is a risk of product failure, because that's the consequence of having recombination between viral strains. It's not that a new viral disease will come up and destroy agriculture. It's that the transgenic crop will be overcome and you'll lose that as a product. Then you're back to what you're doing today which is spraying to kill aphids and that's a valid point.
So I'm trying to show you the observations from over 150 different field sites over three years, where our plants that have the coat protein gene have been naturally challenged with all these different viruses. Just to show you that everything is predictable and safe. In a plant-back experiment with the virus resistant and non-resistant variety Shephody grown as a seed, the grower sprayed his crop with insecticide to control aphids, sent some of the tubers to Florida and they planted them back to look for secondary infection. The transgenics were 100% virus free. The regular Shephodys are 100% virus infected. This illustrates my point that the current control methods aren't affective and they really aren't. I'm told that a potato seed grower knows in their mind that spraying for aphids is worthless. But they do it anyhow, they feel they have to do something.
(Pia Malnoë: It's forbidden in Switzerland) That's probably just as well because it doesn't do anything. This is Russet Burbank again another plant-back experiment, this is the transgenic. These are the regular Russet Burbank, again 100% infection and zero infection. You get more visual symptoms on the variety Russet Burbank than Shepody.
So what have we learned by taking our seed potatoes through the seed certification system? And now we have a actually a third year of data we can add to this. At least for 1995 and 1996 we had a 141 different lots of three different varieties grown at 45 different places all across the USA and Canada. And we know by the virus infection in the lots in the neighbouring plants that weren't transgenic that all the different potato viruses were there and our plants were challenged. And the bottom line is that we had total freedom from infection from any PVY strain - whether it's O or a different strain. We have normal susceptibility and normal reaction to PVA and to other potato viruses. PVA is distantly related. Like we saw earlier, at least in our plants, we're getting basic immunity from all the different strains. So I don't know if recombination of virus to virus will occur and will overcome this protection. We have three years of data that are promising that that won't happen. It looks like PVY and PVA aren't going to recombine to overcome protection either. I've always wondered about resistance management of viruses. We do it with insects. Again this would be product failure. These are big products for us as a business so we don't want them to fail - obviously. But we feel pretty good about the ones that we have today, that the resistance covers all the different strains, that it's extremely high level resistance and that it seems to be behaving that way for three different field years.
We're also using a replicase gene for controlling potato leaf roll virus. In some virus families, coat protein works better, in others replicase works better. I'm sure that we'll find - as we continue to do experiments - other pieces of the viral genome that actually work even better than these. For example what you showed earlier (addressing Pia Malnoë) is very interesting.
So this is necrosis caused by potato leaf roll virus. This is a hugeproblem especially in North America. So we take the replicase gene - something we have always been eating - and again it gives pretty complete control. Again, spraying the insect vector just isn't effective. A field in the state of Washington was sprayed four times with insecticide to kill aphids and still showed severe PLR virus symptoms. Our transgenic received no insecticide application and yet there's clearly no virus. So again the current control methods just aren't effective and they're very expensive. On a 120 acre field like in this example it means a loss of $350,000. The farmer could have lost his farm.
I told you already about the Food Quality Protection Act in the EPA looking at organophosphate insecticide residues in different crops, measuring the exposure in the diet, particularly in children and teenagers. Potatoes are a high percentage of the diet for children and teenagers and thus at the top of the EPA list. Something needs to be done to lower the residues. This technology is a tool that will allow growers to reduce insecticide use by 80%, the pesticide residue in the crop by 90%, because it controls beetles and the most worrying virus problem which is the PLR virus. This is a product that is in big demand and hopefully will be successful. And it will be safer because it is going to allow the EPA to stop use of Temik on potato any more, you can use it on another crop where you have no alternative. That is going to be the sort of trade-off decision growers will be able to make.
Other products in the pipe-line include Roundup-ready potato. In some places this will be a big product because there are weeds in the potato field that are related to potato. Therefore herbicides against them tend to burn the crop. So growers have been asking us for this. This is not something that we set out to do, but sooner or later where our customers hammer on us enough we actually do respond.
The only way to control potato early dying disease, caused by a Verticillium fungus, is to sterilise the top 6-8 inches of soil by fumigation. It costs about $250 an acre and is not exactly the most environmentally friendly thing a potato grower can do. Even then it does not give complete control. The transgenic inoculated with the fungus is fully protected.
The biggest fungal disease is late blight. It is a huge problem in Europe. Growers spray around 14 times a year. I think we have had a breakthrough on that too.
The aim is to give growers the choice. Are they going to grow the crop in the way they have to use chemicals - things that are not good for their family and the next generation? Or are they going to use tools that give them some alternatives?