Bt Cotton -- Another Magic Bullet?

Jane Rissler / Global Pesticide Campaigner v.7, n.1 Mar97

The U.S. Cotton Belt has been abuzz this past year--with talk of Bt cotton. Last spring, farmers planted Monsanto's new genetically engineered (transgenic) cotton at an unprecedented rate--the biggest first-year adoption of a new product in the history of U.S. cotton production. Bt cotton was heralded for its environmental and human health benefits and as a step towards sustainable agriculture since, according to Monsanto, farmers could significantly reduce insecticide use. As they calculated costs and yields at the end of the season, some Bt cotton farmers were pleased with the results; others were angry that Bt cotton had not lived up to Monsanto's claims and they had been forced to spray chemical insecticides. Environmentalists and organic growers were skeptical and worried that they were facing the loss of Bt as a safe, effective pest management tool.

From a short-term perspective, Bt cotton appears to have been a success for Monsanto and for many growers despite an unexpected mid-season outbreak of cotton bollworm. Environmentalists and organic growers, looking at Bt cotton from a different perspective, found the first season disturbing. The failure of the new cotton to control the bollworm confirmed concerns about the adequacy of Bt resistance management plans. In the final analysis, Bt cotton appears to be another short-term, quick-fix product that perpetuates U.S. agriculture's industrial-style farming.

What is Bt cotton?

To create cotton with built-in protection against insects, genetic engineers spliced a Bt toxin gene into cotton. The new gene that enabled the transgenic cotton to produce insecticidal toxin throughout the plant was obtained from a soil bacterium, Bacillus thuringiensis (Bt), an organism well known to many organic and sustainable growers as a valuable tool for pest management. For years these farmers have used Bt in sprays to control insects. Monsanto put the Bt gene in cotton to protect against three pests: tobacco budworm, cotton bollworm and pink bollworm. In the mid-South and Southeast of the U.S., the tobacco budworm and cotton bollworm are major threats while pink bollworm is a problem in Southwest cotton. The Bt cotton is not effective against a number of other pests,including the boll weevil and whitefly.

Last year, through licensing agreements with Delta and Pine Land Company, Monsanto sold two cotton varieties containing the Bt gene, charging farmers a $32-per-acre technology fee in addition to the cost of the seed. The two companies' all-out promotion of the new Bt varieties combined with memories of 1995 losses to budworms prompted thousands of farmers to buy the new cotton seeds. Over 5,700 growers planted Bt cotton on nearly 1.8 million acres--about 13% of the total U.S. cotton acreage[1]. Alabama had the highest adoption rate--77% of its cotton acres[2].

Until midsummer, Bt cotton's first year was fairly uneventful. But in July, alarm bells began to ring. First in Texas and then all the way to the Atlantic coast, farmers began reporting cotton bollworm damage. By the end of the summer, 40% of Bt cotton growers had to spray chemicals to control the cotton bollworm, some more than once[3]. Many farmers were irate, insisting that Monsanto had led them to believe that sprays would be unnecessary. Growers did the best they could with the unexpected outbreak and then began to look toward harvest and the season's final tally of yields and costs.

End-of-the-season assessment

Now that the season is over, how does Bt cotton's first year look? Monsanto and Delta and Pine Land are lauding the product, and conventional farmers are generally pleased, even though some unexpected problems arose[4]. However, a small number of farmers are sufficiently displeased that they are not likely to plant Bt cotton next year. And environmentalists and organic and other sustainable growers who rely on Bt sprays are troubled.

Overall, Bt cotton worked.

In general, conventional growers are enthusiastic about Bt cotton--though individual opinions range from excited to pleased to angry[5]. Eighty percent of 2,200 Bt cotton growers surveyed by Monsanto were "satisfied or very satisfied with the product's overall performance..."[6] Farmers were delighted with budworm and pink bollworm control. Another Monsanto survey of 89 growers reported average yield increases of 7% for Bt cotton and equal insect control costs for Bt and traditional varieties[7].

Some farmers had problems

Farmers reported a number of problems -- some with insect control and others with the cotton plants expressing unexpected agronomic traits. Having to spray pesticides to control the cotton bollworm was probably the biggest disappointment. Many growers now consider Bt cotton to be a one-pest control--against the tobacco budworm in the Southeast and the pink bollworm in the Southwest. Some Texas farmers are so angry that they are suing Monsanto and Delta and Pine Land for falsely representing Bt cotton's ability to control the bollworm.

To the surprise of growers and consultants alike, Bt cotton required more intensive and more expensive scouting than traditional varieties. Long a part of integrated pest management (IPM), scouting fields for insect pests appears to be even more critical with Bt cotton. In some situations, reducing pesticides allowed other insects to thrive, and farmers encountered pests not normally seen in cotton that had been sprayed with broad-spectrum insecticides. Bollworms were also more difficult to scout because in some cases the Bt cotton canopy was denser, the first fruit-set stage was more compressed, or the behavior of the pests changed.

According to many farmers, an additional challenge was Monsanto's failure to provide the information they needed to manage the new crop. For example, growers did not know how to respond to the bollworm outbreak. Many lost money because they waited too long to spray or sprayed when it was not needed. Some farmers incurred additional expense when they had to spray for secondary pests like armyworms and tarnished plant bugs which are typically controlled by budworm and bollworm insecticides.

In addition to insect control troubles, growers were confronted with a number of other unexpected problems. In some areas, the Bt varieties were inappropriate for local growing conditions and failed to produce satisfactory yields. In northeast Arkansas, for example, many farmers are not likely to plant Bt cotton again until the gene is placed in varieties that thrive there. In Arizona under high night temperatures and in Mississippi under hot dry conditions, bolls dropped off the plants. Some farmers reported that bolls set erratically or in irregular patterns. In other situations, growers did not anticipate the need for supplemental fertilizer to support an unexpectedly rapid establishment of bolls.

Many growers had unanticipated difficulties managing the growth of Bt cotton; they often had to apply more chemical growth regulators than on standard varieties. To facilitate picking, farmers typically use chemicals to control the height and shape of the plants and to open bolls all at the same time. Even with additional growth regulators, Bt plants often became too tall and bolls opened erratically. In some cases, Bt cotton required more preharvest chemical defoliants than standard varieties. A second picking in Bt fields was not uncommon. As a result of these problems, some growers incurred higher production costs than for standard varieties--some paid nearly $50 an acre more for inputs[8].

Environmentalists and organic farmers are troubled at the potential loss of Bt

Environmentalists and growers who use Bt sprays are far less sanguine about Bt cotton's first year than Monsanto and conventional growers. Those who rely on Bt sprays worry that widespread use of Bt cotton will accelerate the development of resistance to Bt in cotton pests. If resistance develops, then Bt toxin, whether in cotton or sprays, would be ineffective against the pests, and the environmental benefit of Bt cotton--reduced insecticide sprays--would be lost. Farmers would likely return to chemical spray regimes.

A more troubling consequence would be the loss to organic and sustainable farmers of Bt sprays, one of their most valuable pesticides. If the bollworm does develop resistance, the repercussions will extend well beyond organic cotton growers. Farmers who raise vegetables and other crops will be affected because the bollworm lives on a number of other plants. For example, it feeds on ears of corn, where it is known as the corn earworm, and on grain sorghum, peanuts, beans, peas, alfalfa, tomatoes and other crops. In effect, a bollworm resistant to Bt in cotton will be resistant to Bt sprays that are used against it as it feeds on any crop.

Since Bt toxin is found throughout the cotton plant during the whole growing season, pests are exposed to high levels of the toxin continuously, a situation likely to elicit resistance faster than the intermittent exposure typical of Bt sprays. Scientists agree that it is only a matter of time before cotton pests evolve resistance.

But they also agree that it is possible to delay resistance if farmers incorporate resistance management strategies into their cotton production systems. Without effective management plans, Bt could be lost in just a few growing seasons. Unfortunately, however, scientists do not have enough information to develop management plans that they know will work. A number of theoretical strategies have been proposed; none have been validated in the field.

The failure to control bollworms this past summer confirmed fears that current resistance management plans may not be adequate to retard the evolution of insect resistance to Bt. With the bollworm outbreak, it appeared that one element of Monsanto's resistance management plan for Bt cotton--a high Bt dose--had not been achieved for that pest.

Although concern over resistance management had been raised for many years, the U.S. Environmental Protection Agency (EPA) responded to industry pressure and approved registration and commercialization of Bt cotton and other Bt crops in 1995. Organic growers and environmentalists were successful, however, in gaining a requirement that Monsanto implement a resistance management plan in Bt cotton as a condition of registration. That plan was based on the two strategies that seem to have the best chance of working: a high Bt dose and refuges. Theoretically, a high dose of Bt would kill virtually all targeted pests allowing only rare highly resistant ones to survive. Nearby refuges planted in non-Bt cotton would supply susceptible insects that would mate with the highly resistant ones, thereby diluting the resistance. Under the plan, Monsanto was to provide the high Bt dose while farmers were to plant and maintain refuges.

While we have no independent surveys on how well growers executed the refuge strategy, we do know that the bollworm outbreak indicates that the high-dose part of the plan was apparently not achieved for the bollworm.

Bt cotton in 1997

Reports from the Cotton Belt suggest a mixed reception from farmers for the 1997 season, although overall there appears to be continued enthusiasm for Bt cotton. With nine varieties for sale, compared with two last year, adoption may be broader in 1997 as more farmers find varieties suitable to their climate.

Predictions about adoption are complicated by the possible debut in the 1997 season of Tracer, a new insecticide by DowElanco[9], targeted at the same pests as Bt cotton. Rather than pay the technology fee and take a chance on Bt cotton's uncertain capacity to control the bollworm, some farmers may forgo the transgenic cotton and use Tracer on conventional varieties.

In terms of resistance management, 1997 will be an important year. The cotton bollworm problem is the first major test of EPA's resolve to follow through on the resistance management requirements of conditional registrations for Bt crops. Environmentalists and others have called on EPA to re-evaluate the cotton resistance management plan in light of the bollworm problem. As a result, the Agency is planning to hold hearings this spring on the cotton plan. However, it is unlikely that the Agency will re-evaluate the plan in time to recommend any changes before spring planting begins in March in the southern U.S.

A short-term, quick fix

Looked at superficially, Bt cotton and other Bt crops with their promise of lower insecticide use, appear to be a boon to U.S. agriculture, the environment, and human health. Many claim that Bt crops are a path to a sustainable agriculture. Who would not welcome their widespread adoption?

The story is, however, not so simple. The promised benefits, welcome as they are, are likely to be short lived. Without validated resistance management plans for the new crops, U.S. agriculture is taking a big gamble with Bt. To obtain the advantages of Bt crops for a few years, we may well trade away a valuable public resource, perhaps forever.

Moreover, we probably cannot expect that new insecticidal genes will replace the Bt genes when resistance does develop. Based on what we see coming through the research and development pipeline, it does not appear that genetic engineers will be able to offer a stream of new genes to control cotton or other pests in lieu of chemicals. In just a few years, U.S. cotton production will likely be back to its reliance on synthetic pesticides.

To some, Bt cotton in its first year may have looked like a promising product for sustainable agriculture. In reality, the new cotton is just another in a long line of short-lived, magic-bullet solutions that have dominated U.S. agriculture for the last fifty years--an expensive off-farm input that allows farmers to continue cotton monoculture, the hallmark of today's industrial-style conventional agriculture. A truly sustainable Southern U.S. agriculture will have to look elsewhere for new tools.

Jane Rissler, PhD, is Senior Staff Scientist at the Agriculture and Biotechnology Program, Union of Concerned Scientists, 1616 P Street NW, Suite 310, Washington, DC 20036.

Further reading: Cotton Farming, January 1997, Vance Publishing Corporation; Fiber, January 1997, U.S. Publications, Inc., Memphis, TN; Office of Pesticide Programs, U.S. EPA, EPA Pesticide Fact Sheet on Bt cotton, October 31, 1995; Monsanto resistance management plan for Bt cotton, submission to EPA, January 31, 1995.

References

1. Monsanto, "Bollgard Cotton Update," January 6, 1997.

2. Cotton Inc., Crop Management Seminar, 1997. Fiber, January 1997, page31.

3. Monsanto, op.cit.

4. I have tried to piece together a picture of farmers' reactions to Bt cotton from a number of different sources, including news media accounts, cotton trade magazines, and Monsanto. One of the best sources was the recent Beltwide Cotton Conference in New Orleans, a large annual meeting of cotton producers. Bt cotton was the hottest topic in the hallways and informal sessions.

5. Some farmers are especially angry about Monsanto's technology fee. It appears that nearly all farmers consider the fee to be excessive. The company plans to charge the same amount in 1997.

6. Monsanto, op.cit.

7. Ibid.

8. Presentation by Chuck Farr, Beltwide Cotton Conference, New Orleans, LA, January 9, 1997.

9. Tracer is not registered for use in the U.S., but DowElanco anticipates receiving federal registration for use in cotton in time for the 1997 season.

Bt Crop Basics

What are Bt crops?

An insecticidal toxin gene from Bacillus thuringiensis (Bt), a naturally occuring soil bacterium used as a biological pesticide since the early 1960s, is cloned and inserted into a crop plant. The plant then produces its own toxin in most, if not all, parts of the plant.

Why develop Bt crops?

To allow crops to ward off insect pests without applying synthetic insecticides. Amidst growing concerns about the human and environmental risks of chemical pesticides, genetic engineers are giving crops the ability to defend themselves against pests by producing their own insecticidal toxins.

What crops have been genetically engineered to produce Bt?

In 1996, three Bt crops-corn, cotton and potato - were grown at commercial scale for the first time in the United States. The three crops were planted on an estimated two million acres with Bt cotton accounting for the vast majority of the acreage. Additional varieties of these crops will be planted in the 1997 season.

Since 1987, other Bt-producing crops have been field tested in the United States, including apple, canola (rapeseed), cranberry, eggplant, poplar, rice, spruce, tomato and walnut. Some of these will move into the food supply in the next few years. Still other Bt crops are under development in company and university laboratories.

Who is developing Bt crops?

Chemical, seed and biotechnology companies. Examples include Novartis (Ciba-Geigy and Sandoz), Monsanto, Delta and Pine Land (partly owned by Monsanto), Pioneer Hi-Bred (licensing agreements with Monsanto), DeKalb (partly owned by Monsanto), Calgene (controlled by Monsanto) and Mycogen.

What are potential environmental problems associated with Bt crops?

The two major worries about Bt crops are that pests will develop resistance to Bt toxin and that the Bt gene will become established in wild relatives of Bt crops.

Insect resistance to Bt. Because insect pests feeding on Bt crops are exposed to toxins continuously, they are likely to evolve resistance. Development of resistance would render ineffective both the Bt genes in transgenic crops and Bt toxins in sprays. Because of the resistance problem, scientists have estimated that the useful life of Bt in major crops like corn, cotton and potato could be as short as two to three years unless effective resistance management plans are implemented. Otherwise, the environmental benefit of Bt crops would be short-lived as many conventional farmers would likely return to chemical pesticides. Moreover, Bt resistance would also mean the loss of Bt sprays important to organic and other sustainable farmers.

Bt gene flow to wild relatives. Where Bt crops are grown near wild relatives, it is highly likely that the Bt gene will transfer to the wild populations-as a result of movement of pollen from the crop to the relatives. Some of the resultant wild plants may produce enough Bt to ward off insects that normally feed on them. What this may mean in natural ecosystems we don't yet know-there has been little research in this area. In some cases, the new gene may strengthen the wild plant allowing it to become a weed in farmers' fields. With the Bt advantage, some plant populations may be able to displace other populations in natural ecosystems, altering local biological diversity. Such an outcome could be particularly troublesome in centers of crop diversity, areas of the world that contain substantial populations of wild relatives. Plant breeders often rely on genes from these wild relatives to enhance crops.

How are Bt crops regulated in the United States?

Three federal agencies oversee the commercialization of Bt crops. Before the Bt crop can be sold, the U.S. Department of Agriculture must determine that it will not become a plant pest. Companies must register Bt crops as pesticides with the Environmental Protection Agency (EPA), which evaluates human health and environmental risks. As it has for Bt corn and Bt cotton, EPA may also require companies to develop and implement Bt resistance management plans as a condition of registration. Finally, the Food and Drug Administration, through a largely voluntary program, consults informally with companies on the safety of transgenic crops as food.

For further reading:

F. Gould. 1988. Genetic engineering, integrated pest management and the evolution of pests. Trends in Biotechnology 6: S15-S18.

B. Lambert and M. Peferoen. 1992. Insecticidal promise of Bacillus thuringiensis. BioScience 42:112-21.

W. McGaughey and M. Whalon. 1992. Managing insect resistance to Bacillus thuringiensis toxins. Science 258:1451-55.

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