Here's a question for the environmental activists: "Just what do you folks want? What exactly is your objective?" I've been wondering that as activist groups in Europe and the United States have attempted to generate concern about crops that have been genetically modified to ward off insects. The activists are using the same types of tactics they have used to oppose chemical pesticides. Now, when scientists have developed a non-chemical insect control by inserting a single gene into a plant, the activists oppose that.
The gene comes from a soil organism, Bacillus thuringiensis (Bt), that has been used in spray and powder form for years. Opponents of chemical pesticide have endorsed the sprays and powders because they are effective against target insects and harmless to birds, mammals and beneficial insects.
Through biotechnology, the benefits of Bt can be extended to millions of acres, without the costs of fuel and the time that go with repeated applications of powders or sprays. And any farmer who knows how to plant a seed can have insect protection, whether he is an illiterate subsistence farmer in a developing country or whether he is a university-educated grower.
The importance of using technology to enhance crop production cannot be overstated. My research over the years has shown that there would be tremendous crop losses without the protection of pesticides. The reduction in rice yield would be 57 percent, and 32 percent in corn. We would not have met global food demands during the past 50 years without pesticides. And we will not be able to feed the growing global population in the next 50 years unless we continue to increase crop yields.
Chemicals can be used safely and the risks posed by pesticides are more than offset by the benefits during the post-war years when global population has more than doubled. But I can appreciate that well-intentioned people would want to minimize the potential risks associated with pesticides. I have to admit, though, that I am puzzled when the same people oppose a technology that would help accomplish this goal. They obviously do not know what it takes to produce a crop on a large scale.
In certain regions of the Southern United States, cotton growers have to spray up to seven times a year to control insect species that would destroy crops. Bt cotton controls some but not all of those species, so farmers who plant Bt cotton still use some chemical sprays. If their farm is in a region with high pressure from many species, they may use more insecticide than a non-Bt grower in another region, as a recent USDA report showed. But the key point is that growers who plant Bt cotton, which provides better than 95 percent control of bollworm and budworm, can eliminate the sprays they use for those insects. In 1998, according to the National Agricultural Statistics Service, 2 million fewer pounds of insecticide were used to control bollworm and budworm than in 1995, before Bt cotton was introduced.
Not all of this can be attributed to Bt cotton, but a lot of it can. Just as important as the reduction in gallons sprayed is the reduction in the times a farmer has to spray his fields, with any attendant risk to himself or the environment. A three-year study in North Carolina showed that on average, farmers with Bt fields applied insecticides 0.7 times compared with 2.7 times for conventional fields. Without protection of chemicals or genetics, cotton losses would be 63 percent per year.
The major pest controlled by Bt corn is the European corn borer. This devastating insect bores into cornstalks, interrupting the flow of nutrients to grain, resulting in substantial yield losses. Weakened stalks fall over in the wind. When borers feed on ears, they allow disease to enter the corn.
The pest is a major economic drain on the corn crop, but many farmers do not use chemicals to control the pest because it can tunnel into the corn before insecticide can be applied. Before Bt corn, growers took the loss. However, in some regions where corn-borer pressure is the worst, farmers have paid several dollars per acre to have their fields scouted for the first sign of corn borer. Then they sprayed. Extension service entomologists estimated in 1996 that nearly 1.5 million pounds of an insecticide-active ingredient were used to control the European corn borer. Bt corn, which is nearly 100 percent effective against the pest, gives farmers another option that should be welcomed by people who oppose pesticides.
The Bt technology, and other promising biotechnology developments, have the potential to substantially increase yield, improve economics for farmers and help meet the incredible demand for food that will come as the population nearly doubles. It can accomplish this while offering an alternative to chemical inputs. Such a technology deserves to be embraced -if not with open arms, at least with an open mind.
Ron Knutson is professor of agricultural economics at Texas A&M University and director of the Agriculture and Food Policy Center. Since 1990, he has conducted three studies of the impacts of reduced pesticide use in agriculture.
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Last Updated on 10/5/99
By Karen Lutz