Farmers best at gauging value of biotech crops


I agree that it is farmers who are the best measure of whether biotech is a good thing or not. I have spent many hours sitting at the kitchen tables of Midwest farmers who are still family farms even though they tend 2-12 thousand acres. I have talked with the major sweet corn producers to see if they would prefer to be growing Bt corn instead of spraying every two days to control worms. I've talked to Ph.D. personnel at wineries like Fetzer who cannot rationally defend their position in support of the Mendocino GMO ban.

I'm a consultant to the biotech industry as you can see from our Web site (www.cirruspartners.com) but over my career I've worked on everything from chemical to cultural to biological to chemical to “organic” control of pests. I've seen the good and the bad of all of these things.

I'm as frustrated as I sense you are about how this is playing out. I've taken to writing to every reporter and industry person I can to offer help in getting a realistic perspective on what is happening. I asked a reporter in Arcada to think about what percent of their food is produced locally. I ask Fetzer to explain how genetic contamination could occur versus the reality that they have grown different varieties of grapes 8-12 feet apart for decades without issue. I send e-mails to the president of Humboldt State offering information because from what I've heard, he is the only even marginally pro-GMO spokesman in the region.

Sentiment blocks benefits

At one level one could minimize the importance of the anti-GMO initiatives in these marginal agricultural regions. Unfortunately, the reality is that anti-GMO sentiment has already effectively blocked many very beneficial traits from becoming mainstream (Bt sweet corn, herbicide tolerant sugar beets, virus resistant swash, longer shelf life bananas, Bt and virus resistant potatoes along with bruise resistance, higher solids, and the ability to store at lower temperatures to prevent soft rot without accumulation of sugars that cause browning).

I'm not sure whether there is a way to head off this insanity. As Mark Twain said, a lie is half way around the world before the truth gets it's shoes on. I'm working on the shoes and hoping for a comeback.

Steve Savage
San Diego, Calif.

Bt corn as best strategy needs additional context


The claim made by Bruce Chassy and Drew Kershen that Bt corn presents the best strategy for preventing neural tube defects (NTD) [http://westernfarmpress.com/news/10-27-04-Bt-corn-birth-defects] needs some additional context.

The interplay between fumonisin levels, pest damage, and the action of fumonisin to block folate-uptake, coupled with the data showing fumonisin levels to be considerably lower for Bt corn than for conventional or organic corn (both in the field and in dry-milled corn products) is provocative and compelling. However, the authors fail to discuss some of the areas where more research is necessary before any conclusions are possible concerning the prospect of reducing NTD rates with this agricultural technology.

Reducing the rate of NTD among women of Mexican descent living in the U.S. to that of non-Hispanic white women would result in the prevention of between 188 and 628 cases of NTD each year, representing a decrease of between 5 percent and 20 percent in total cases (CDC National Center for Health Statistics and Suarez, et al. 2000. American Journal of Epidemiology 152: 1017-1023).

The degree to which lowering intake of fumonisin alone among Mexican-American women would reduce NTD rates is unknown and needs to be investigated further. Evidence that folic acid fortification does not reduce NTD incidence among women of Hispanic descent (Shaw et al. 1995 Epidemiology 6:219-26) provides corroboration to the idea that reducing fumonisin intake would also reduce incidence of NTD. The problem comes when the authors attempt to fit Bt corn into this picture.

Fumonisin contamination comes, in part, as a result of pest damage, which is reduced in the case of Bt corn. Contamination also results from “environmental factors such as temperature, humidity, drought stress, and rainfall during pre-harvest and harvest periods… (and) optimal growth of fumonisin-producing mold that leads to increased levels of fumonisin in the raw corn can occur when the moisture content of harvested raw corn during storage is 18-23 percent,” according to the FDA Center for Food Safety and Applied Nutrition.

Further, the levels of fumonisin found in different dry-milled corn products can vary significantly, from 0.15 parts per million (ppm) in degermed are produced from Bt, conventional, or organic corn is also unknown.

Since prevention of pest damage is behind lower fumonisin levels in Bt corn, it would behoove the authors to describe the degree to which this sort of damage is actively avoided in convention and organic cultural methods, and provide the reader with information on the potential of each of these methods to reduce pest damage. In other words, if conventional and organic corn farmers are simply not making as much of an effort to control pest damage as is represented by Bt corn technology, it stands to reason that fumonisin levels would be higher for those methods. That does not necessarily mean that Bt corn is an inherently better method for reducing fumonisin levels.

Resistance development

Development of resistance among pests is also a major issue of concern with Bt corn, requiring that farmers plant significant acreage as ‘refuges’. The authors fail to point out that, the development of Bt-resistant pests presents the very real possibility that fumonisin levels might actually become higher in Bt corn products than in those made from conventional or organic corn. This possibility, added to the lack of knowledge linking levels of dietary fumonisin intake to increased risk of NTD, it seems to be at the very best an exaggeration to say that Bt corn presents the best strategy for preventing NTD. We really don't even know whether it is the best strategy for reducing fumonisin levels in a field or refined product context. Given the history of capital- and technologically-intensive applications as failing to meet the needs of farmers in developing nations, it seems especially problematic to refer to Bt corn as a promising strategy “in the African context.”

Might not an attempt to change cultural practices around the processing and consumption of corn products in order to reduce exposure to fumonisin be a better public health approach?

More research on the relationship between cultural, storage and processing methods associated with corn, fumonisin levels, and potential health impacts associated with fumonisin in the diet is very much needed. That Bt corn presents a promising strategy for reducing fumomisin levels in corn products should be investigated further and compared to other explicit strategies to reduce fumonisin levels.

Josh Miner
Food System Analyst and Food and Society Policy Fellow
University of California
Cooperative Extension, Alameda County, Calif.

Bt corn effective, simple way to reduce fumonisin

In response to our article — “Bt corn reduces serious birth defects” (28 Oct. 2004) — Josh Miner agrees that reducing consumption of fumonisin-contaminated corn likely reduces birth defects. He contests our assertion that widespread planting of Bt corn would help accomplish this reduction.

Mr. Miner objects to our conclusion that Bt corn is the “best” and “only” way to reduce fumonisin intake and consequently lower the incidence of birth defects. The words “best” and “only” do not appear in our article because we know that the world is too complex to warrant that conclusion. But we know of no other approach to reducing fumonisin exposure that is as effective and simple as Bt corn. Scientific studies from several continents showed that Bt corn typically has 5-20-fold lower level of fumonisin than other corn crops.

Mr. Miner observes that post-harvest mold contamination can cause fumonisin contamination. Obviously to achieve maximal reduction of fumonisin in corn products, farmers and grain-handlers need to avoid post-harvest contamination. The published scientific studies, however, point to insect damage as the major route of fumonisin contamination. No regime of proper post-harvest storage and handling can eliminate fumonisin already in the corn.

We are talking about a relative reduction of exposure to fumonisin. It is unrealistic to think that we will ever achieve absolutely zero fumonisin exposure. Even Bt corn suffers some insect damage — often from insects not sensitive to the specific Bt protein present in the corn. The point remains though that if we reduce the exposure to safe levels, we improve public health.

Mr. Miner asks why conventional and organic farmers produce corn with higher levels of fumonisin and if such levels are inherent in their products. Entomologists tell us that there is essentially nothing that a farmer can do in conventional and organic agriculture to control corn borers. Conventional chemical sprays do not reach corn borers once they have drilled into a plant. Organic farmers face even greater challenges in controlling boring insects because organic production standards prohibit using synthetic pesticides. Inherently Bt corn not only is a better method for controlling boring insects, it is the only effective method thus far developed.

Mr. Miner expresses a fear that insects will develop resistance to Bt corn. Insects have developed resistance to almost every insect control technology used in agriculture. But even if resistance arises, we would be no worse off than we are today — i.e. with no adequate means to control boring insects and mold-produced fumonisin.

Thoughtfully, regulators, developers, and farmers are not passive about resistance. Governmental authorities require developers of Bt crops to have proven resistance management plans in place before the authorities approve the crops. EPA has reviewed the effectiveness of these plans and has concluded that Bt crops perform better than expected. Indeed after 9 years studies show no resistance has emerged in the field. Moreover, developers are not waiting for resistance to appear. They have stacked multiple Bt traits into single crop varieties and developed crop varieties with alternative control mechanisms.

Developers have taken effective, approved measures to thwart resistance. Farmers will respond to any resistance within a particular corn variety by switching to new varieties with stacked traits or alternative control mechanisms. We should take advantage of Bt corn benefits for women and children now rather than worry about when, if ever, resistance will occur in the future.

Mr. Miner states a concern about capital intensive high technologies failing in the developing world. We share his angst. Fortunately, with Bt corn, the technology is built into the seed. The farmer does not need to change his practices and may not need to make new capital investment.

Readers are referred to http://www.agbioforum.org/ Vol. 7 (Nos. 1&2) for a fuller discussion of issues surrounding the development and deployment of biotechnological solutions for agricultural challenges in the developing world. With the technology in the seed, farmers in developing countries are likely to gain greater benefits than farmers in developed countries.

We repeat — not our words — the words of an African speaking about the health value of Bt corn in Africa:

Izelle Theunissen of the Medical Research Council of South Africa has written, “So despite the current discussions surrounding GM foods, it appears that Bt maize hybrids could play a major role in lowering fumonisin levels in maize products, which should ultimately enhance the quality and safety of maize for animal and human consumption, particularly in the African context.”

We close by noting the irony that activists opposed to transgenic crops demand governmental action in accordance with the precautionary principle. They demand that the precautionary principle be used when any hypothetical hazard exists to public health or the environment — in the absence of complete scientific understanding. Yet when we refer to scientific evidence establishing that Bt corn reduces fumonisin exposure, Mr. Miner calls for more research. When we provide evidence of present physical harm to women and their babies, Mr. Miner abandons the precautionary principle.

To be blunt, ignoring real risks but being precautionary about hypothetical hazards damages both human health and the environment.

Sincerely yours,
Bruce M. Chassy, Ph.D.
Executive Associate Director Biotechnology Center
University of Illinois
Drew L. Kershen
Earl Sneed Centennial Professor College of Law
University of Oklahoma

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