Ten Reasons why farmers should think twice before growing GE crops
E. Ann Clark, Plant Agriculture, University of Guelph (firstname.lastname@example.org)
The tide appears to be turning against GE crops, but farmers may well be the last ones to know. Many citizen and professional groups are now on record, urging everything from an outright moratorium to a slower, more reasoned approach. For example, on 2 June 99, the National Federation of Women's Institutes voted 7055 in favor vs. 368 against a 5-year ban on the growing of GE crops in the UK.
My goal today is to give you some of the agronomic reasons why farmers should think twice about growing genetically engineered crops.
1. Do you really need what they offer in the first place? For example,
Are European cornborers (Ostrinia nubilalis (Hubner) sufficiently predictable on your farm as to justify the extra expense of growing Bt hybrids as insurance? Sears and Schaafsma (1998) reported that infestations had to be high enough to cut yields by at least 5-8 bu/ac before Bt-corn was economically competitive. They further noted that conventionally-bred cornborer-resistant hybrids performed as well as Bt-hybrids under low-to-moderate cornborer infestations. Thus, unless cornborer infestation is high, you have other, less costly, options besides Bt-corn.
Table 1. When does it pay to grow Bt-corn? (adapted from Sears and Schaafsma, 1998)
|Cornborer Infestation||Yield Protection by Bt-Corn||Bt-Corn Economically Justified?||Conventionally-Bred Cornborer Resistance Sufficient?|
Transgenic solutions come with a price tag that is high, both in terms of dollars and in indirect costs (see below). Whether Bt or herbicide-resistance, be sure you can justify it economically before trying it out.
2. How much of a yield loss can you experience and still make enough money to justify growing GE crops? And keep in mind, that if cornborer risk is high enough to justify using a Bt hybrid, then you'll also need to factor in yield loss on the 20% or more of unsprayed "refugia" set-aside that you are expected to plant to a non-Bt hybrid - without insecticidal protection..
Contrary to what has been promised, GE crops often do not yield more and not infrequently yield less than the best available conventionally bred cultivars and hybrids. Why? Because not all genetic backgrounds within a given crop will tolerate a transgene1, and those that will are not necessarily the highest yielding ones. Further, there is a metabolic cost to expressing herbicide-resistance or the Bt-endotoxin. So, if you were expecting a yield gain - as promised, if we are going to "feed the world" - then you may well have been disappointed. And the fault was not necessarily yours, no matter what they told you.
A recent review of 40 soybean varietal trials in the north central region of the US by Oplinger et al. (1999) found a mean 4% yield drag in RR soybeans. Even comparing the top 5 varieties from each, RR still yielded 5% less than conventional soybeans. In Ontario, most recent data show a 1-3% mean yield drag in RR soybeans (Table 2), and keep in mind that this is relative to the trial mean - not to the highest yielding cultivars. However, the soybean breeder advises that the yield gap is closing. Nonetheless, there is a cost to the crop from expressing the genes for Roundup resistance, and it manifests itself in lower yields.
Table 2. Two-year mean yields of Roundup Ready soybean cultivars (n=8) (% of trial mean yield, n=57 cultivars) adapted to the 2900-3300 heat unit zone (from 1999 Report Ontario Soybean Variety Trials, Table 4)
|Variety Designation||Clay Soil||Loam Soil||Proprietor|
3. When are they going to get it right? The evolution of pest resistance to Bt is a foregone conclusion, as virtually everybody will admit. Pesticidal plants like Bt-corn are no different than DDT or atrazine - insects and diseases, and to a lesser extent weeds, are extremely well adapted to evolve resistance whenever faced with a powerful and efficient "screen" - like tens of millions of hectares of cropland all expressing the same toxin.
The only source of contention among scientists is "when" and how to delay resistance. The high dose/refugia model which has been widely promoted by both industry and government proponents was supposed to be the best available strategy to forestall resistance, but you may have noticed that the size of the recommended set-aside has increased just about every year. When Bt hybrids first came out, producers were told to hold back a 5% refugia (to plant to a non-Bt hybrid). Then it was 10%, and now it is most commonly recommended as 20% (plan submitted to the US EPA by Monsanto, Mycogen, Dow Agrosciences, Novartis, and Pioneer Hi-Bred; AgNews, 23 Apr 99; also by the Bt Corn Coalition to the Plant Biotechnology Office of the CFIA in October 1998), although some are calling for 40%. Why the confusion? Why is the figure changing - and always upwards?
The confusion is caused because those promoting refugia as the best solution have not done their homework. This is a clear example of a general and pervasive problem with agricultural biotechnology - namely, technology has preceded science. Ag biotech has been released prematurely, for reasons of profit, before the scientific evidence has been developed. Proponents, and the researchers in their employ, did not take the time to answer some of the key questions regarding the effectiveness of refugia in restricting evolution of cornborer resistance.
And unfortunately for proponents of this model, many of these untested assumptions have now been challenged by recent research published in the most prestigious journals. What we now know is that the high dose/refugia model is unlikely to work, at least for cornborer.
Table 3. Key assumptions of the "high dose-refugia" model of resistance management.
|No.||Assumption||Evidence to the Contrary|
|1||Major resistance genes must be very rare||In diamondback moth, one of eight species that have already evolved resistance to Bt, Tabashnik et al. (1997) showed that resistance is not rare - its actually 10X higher than the highest previous estimate|
|2.||Resistance genes must be nearly recessive||According to Huang et al. (1999), resistance in ECB is dominant, while in other pest lepidopteran species, resistance varies from recessive to incompletely dominant. Furthermore, resistance varies not only among species, but also among types of Bt endotoxins, e.g. CryIAc, CryIAb, CryIIA|
|3.||Non-Bt refuges must provide susceptible pests to mate with resistant ones; requires random mating and suitable dispersal distances||Cornborers consuming Bt (and living) typically suffer delayed development, which causes them to reach reproductive maturity out of phase with their neighbors in the refugia. They won't be able to mate anyway.|
4. Do the GE crops, in fact, do what is promised? Reduce production costs? Reduce pesticide applications? Increase yield? Increase profit?
Costs and profits are a hard issue to address in the abstract, as much varies with weed and insect pest pressure and other farm-specific issues. Yield is already known to be lower - or at best, no better - than conventionally bred crops. But what about insecticide use? If you use Bt, then you don't need to use insecticides, right? And that protects both you and the environment, and that's good, right?
Indeed, Monsanto made just such a claim in a press release dated 21 May 99, in response to recent research showing an adverse effect of Bt pollen on Monarch butterflies (see below). Monsanto stated:
"In 1998 use of Bt insect-protected corn reduced or eliminated the use of broad spectrum chemical insecticides on some 15 million acres of US farmland".
Now, that would be a pretty impressive achievement, if it were true. So, let's see - some 71.4 million acres of corn were grown in the US in 1998, and data from the USDA National Agricultural Statistics Service (http://www.usda.gov/nass/pubs/rptscal.htm, courtesy Chuck Benbrook, personal communication) shows
|Insecticide||% of 71.4 million ac treated in the US||Target Pest|
|bifenthrin||2||rootworms, soil insects|
|dimethoate||1||possibly European cornborer (ECB)|
|fipronil||1||rootworms, soil insects|
|lamba-cyhalothrin||2||some for ECB; mostly soil insects|
|methyl parathion||1||rootworms, soil insects|
|permethrin||2||possibly partly for ECB|
|tebupirimiphos||3||rootworms, soil insects|
Further detracting from Monsanto's claims, insecticide usage in the US agriculture has not diminished despite the increasingly prominent role of Bt-crops in the last several years. Allocating 30-50% of US crop acreage to Bt crops has not reduced use of insecticides.
So, if GE crops don't increase yield, lower costs, increase profits, or reduce risks of insecticide use - just what is it that GE crops DO do?!
5. How will genetic pollution, from your fields and from your neighbors' fields, compromise your ability to control weeds on your own land? The term "genetic pollution" refers to the fact that pollen moves - sometimes great distances. And when transgenic pollen moves, it carries with it transgenic traits - like herbicide resistance. Pollen of canola can move 8 km, while that of both corn and potato can move about 1 km. Gary Stringam, a professor at the University of Alberta has found that canola could out cross and produce 5-6% contaminated plants up to 400 m from the original source (MacArthur, 1998b). All of this makes it difficult to imagine how Monsanto and others can hold onto their precious genes - or for you as a farmer to avoid genetic pollution of unwanted genes - either moving to your fields from your neighbors, or to your neighbors fields from your land.
Consider the case of Tony Huethers, who farms near Sexsmith, Alberta. In 1997, he planted two fields, separated by 30 m, to canola. On the west side, he planted Quest, a Roundup(glyphosate)-resistant cultivar, while on the east side, he planted 20 acres of Innovator, a Liberty (glufosinate)-resistant cultivar, and the rest of his 140 ac field to 45A71, a cultivar that is resistant to Pursuit (imazethapyr, an ALS inhibitor) and Odyssey.
In spring of 1998, two applications of Roundup to the east field - the one sown in 97 to Innovator and 45A71 - killed all his weeds, except for a healthy population of blooming canola! It was apparently, and predictably, Roundup resistant canola, and was thickest near the road.
The biotech manager for Monsanto in Saskatoon - Aaron Mitchell - said "We always expected a level of natural out cross would occur within the species", and that the source was likely native pollinators. He stated that the potential for cross pollination was already well known to seed companies and researchers, and that "farmers need to talk to their neighbors about the canola they grow" (MacArthur, 1998a).
6. Will genetic pollution expose you to lawsuits or other legal actions by neighbors, analogous to spray drift? The Royal Institution of Chartered Surveyors (RICS; with a membership of 100,000) surveyed 100 chartered surveyors out of the 6,000 who specialize in rural properties (Table 5).
Rural land managers in the UK are uneasy about the implications of growing GMO's, in such areas as land value (74%) and risk of future lawsuit (71%). More than 70% of the chartered surveyors would advise neither land owners nor tenants to grow GMO's. Almost 60% believe that growing GMO's on land would lessen its future value, and 64% think it would make it harder to sell the land in the future. A whopping 76% support a register of all land where GM crops have been grown, with 68% concluding that the register should be open to the public.
Have we in Canada even begun to think in these terms?
Table 5. Survey of Royal Institution of Chartered Surveyors specializing in rural practice, regarding attitudes toward GMO's and land valuation (June 1999)
|Issues Concerning Clients...............||YES||NO||Undecided|
|Neighbors growing GM products?||77||6||17|
|Effects on land values?||74||12||14|
|Should there be a clause obliging tenants to notify landlords if they intend to grow GM crops?||90||4||6|
|Would you advise landlords to allow tenants to grow GM crops on their land?||11||75||14|
|Would you advise tenants to grow GM crops on their land?||11||73||17|
|In your opinion would the growing of GM crops affect the value of land?||58||16||26|
|In your opinion would the growing of GM crops on neighboring land affect the value of client land?||43||32||24|
|In your opinion would the previous or present growing of GM crops make land more difficult to sell?||64||24||11|
|Would you support the maintenance of a register of all land where GM crops have been grown?||76||19||5|
|Do you think such a register should be publicly available?||68||27||5|
|Will you ask about the GM history of a site when carrying out a valuation?||89||7||4|
An article in the UK Farming News (18 June 99) notes that farmers are increasingly unwilling to grow GMO trials on their farms, specifically because of fears of legal damage claims from neighbors. One underwriting manager, Sid Gibson, reportedly advised that
"The big unknown is where there is a risk of cross-contamination. Farmers considering growing GM crops should get their legal advisers to look at the contract very carefully. Responsibility should be with the biotech company or institution carrying out the trials."
7. Who is responsible/liable for GE risks? In Spain, those who produce or plant GMO's are being obliged to contribute to a US $100 million insurance fund to cover environmental accidents. In other countries, disaster plans are being drawn up, complete with sterilization of large tracts of land in the event something gets out of hand.
Did you know that the life science companies are reportedly running without catastrophic or long-term disaster insurance - partly because it cannot be calculated, but mostly because no one will insure them?
So, where does that leave you?
8. How will you control mosquitos when the bats are gone? The balance of nature is more than just a teaching tool for grade school students. It is reality - even in today's highly artificial agricultural environment. It has been said that the only really effective control of insects is that provided by nature, by the competition, predation, and parasitism of one organism on another. Just as killing off the wolves unleashes deer populations and allows them to skyrocket beyond the carrying capacity of their environment, so too our efforts at pest control can often have unintended side effects on other insects or microbes.
For example, bats are an important vehicle for mosquito control in our area, but when they can't get mosquitos, they eat moths and butterflies. Now, moths and butterflies are important because they are the class or insects targeted by Bt corn - so, one unsavory side effect of Bt corn could be fewer moths and butterflies, including Monarch butterflies (Losey et al., 1999), fewer bats, and........... more mosquitos?
Another example of an adverse effect of Bt radiating out into the wider environmental community has been reported from Switzerland and Scotland. One of the insects which normally feeds on cornborer is a beneficial called the green lacewing, which favors soft-bodied insects such as cornborer and aphids. Unfortunately, green lacewings are harmed (killed or suffer delayed development) by Bt, whether they ate it directly or after eating cornborers which had been reared on Bt corn. The same thing happened with ladybugs eating aphids which had been raised on transgenic (snowdrop lectin) potatoes.
So - the adverse effect of these plant pesticides affects not just the target organism but beneficials, such as ladybugs and green lacewings too. And of course, this could have additional effects on natural pest control for other crop and garden pests.
9. Is it safe to eat GE foodstuffs? The government says so, but is that enough? Consider what professionals working in the field have to say:
a. On 17 May 99, the mainstream British Medical Association, representing 115,000 doctors, published a statement calling for an open-ended moratorium on the planting of GM crops, a ban on releasing GMOs into the environment, and a review of the World Trade Agreement to ensure that human health and safety take precedence over global trade in foodstuffs and seed (Frith and Murphy, 1999). Their specific concerns included the use of antibiotic resistant marker genes, which were regarded as posing a slight but "completely unacceptable risk" of enhancing drug-resistant bacteria. Their general call was for much greater scientific certainty about risks of GMOs.
b. A survey of Canadian dieticians shows a pronounced unwillingness to trust biotech proponents to provide unbiased information on food safety issues (Sheeshka, 1999)
c. Transgenic DNA can survive long enough in the gut to transfer genes into intestinal microflora. Because almost all commercial GE crops are bred using antibiotic resistance genes as a marker (this is unrelated to the agricultural use, just part of the breeding process), this means that consuming GE foodstuffs can allow genes for antibiotic resistance to move into the E. coli and other microbes that are naturally present in your stomach, or that of your child.
Plasmids, which are a special kind of vector commonly used to insert transgenes into chromosomes, have been tracked not just in the stomach of rats, but across the intestinal wall and into the nuclei of rat cells. Even more alarming, these same plasmids have been followed across the placental barrier and into the nuclei of embryonic rats in utero. This gives new meaning to the phrase that "you are what you eat"!
Do we actually know enough to be able to state with confidence that the food is safe? Are we asking the right questions?
10. Who is going to buy your grain, and how confident are you of demand for GE grains(or meat or milk) this fall?
Even locally, concern is growing among consumers about the implications of growing GE foodstuffs. For example, in an 18 June 1999 Corner Post commentary, Elbert van Donkersgoed questioned the use of some kinds of biotechnology on the farm. While noting the potentials, he emphasized also the risks, even going so far as to state that "disaster is possible".
He contrasted Integrated Pest Management with biotechnology, noting that IPM requires monitoring of pest populations before deciding to spray - essentially, "knowing what we are doing" before we do it. Conversely, the biotech equivalent is Bt-crops which synthesize a plant pesticide in every cell of every plant, throughout the season, irregardless of pest populations. He states that IPM is "essential to the overall credibility of the use of pesticides in agriculture. Some biotechnology is eroding that credibility."
And then, there is the export risk. Did you know that Canadian canola growers lost $30 million in export sales to Europe in 1998 alone, because consumers refused to accept GE canola oil? Japan is not far behind.
This spring (Reuters, 20 April99), Cargill and ADM announced that they would not buy unapproved GMO corn, that is corn hybrids that are acceptable to European buyers. Roundup Ready and Liberty Link corn hybrids are disallowed. I'm told that some elevators in Ontario are already declining to accept any GMO grain, because they won't be able to sell it in Europe.
Just this week, major supermarket chains in the UK have begun to pull off the shelves meat products that could have been produced from GMO grains.
In short, demand for GMO grain and products, or livestock produced from GMO grains, is rapidly drying up. The high-handed behavior of the US, Canada, Australia, and three South American nations in refusing to sign the Biosafety Protocol at Cartagena, Colombia this winter is beginning to look short-sighted. As acknowledged even by Glickman, Secretary of Agriculture in the US, you cannot force people to eat something they don't want to eat.
So, when deciding whether or not to grow GE crops next year, I'd encourage you to consider:
1. Do you really need what they offer, and is GE the best way to deal with it, given the likelihood of higher costs and lower yields?
2. Be very aware of insurance/liability risks from neighboring farmers (for genetic pollution), environmentalists (for Monarch butterflies and other issues), and consumers (for food safety).
3. Don't assume that because it is in the marketplace, that it is "safe", has been tested for "environmental risk" (a la Monarch butterflies), or is necessarily in your best interests. Government is not asking the right questions. Trade interests are taking precedence over the interests of producers, consumers, or the environment. The world doesn't want our grain. Don't get caught in the middle.
4. Only industry data stands between you and potential risks from genetically engineered crops. Are you willing to entrust these companies with this responsibility?
Frith, M. And E. Murphy. 1999. BMA Calls for ban on GM crops and food. PA News 17 May 99
Huang, F., L.L. Buschman, R.A. Higgins, and W.H. McGaughey. 1999. Inheritance of resistance to Bacillus thuringiensis toxin (Dipel ES) in the european corn borer. Science284:965-967.
Losey, J.E., L.S. Rayor, and M.E. Carter. 1999. Transgenic pollen harms monarch larvae. Nature 399:214.
MacArthur, M. 1998a. Canola crossbreeds create tough weed problem. Western Producer, 15 October 98.
MacArthur, M. 1998b. Resistant canola expected. Western Producer, 15 October 98.
Sears, M. and A. Schaafsma. 1998. Responsible deployment of Bt corn technology in Ontario. http://www.cfia-acia.agr.ca/english/plant/pbo/btweb2e.html
Tabashnik, B.E., Y-B Liu, N. Finson, L.
Masoson, and D.G. Heckel. 1997. One gene in diamondback
moth confers resistance to four Bacillus thuringiensis
toxins. Proc. NationalAcad. Sciences 94:1640-1644.
1Particularly in corn; in soybeans, only some constructs are able to regenerate from tissue culture