culture makes it resistant to change. Headley cites Department of Agriculture data indicating that about half, or more than 1 million, of all farmers apply chemical pesticides. This, in turn, means that more than 1 million decisions are made annually about use of chemicals. Farmers see pest problems and can act on them quickly and unilaterally. This sort of decision-making frame work, Headley explains, doesn't lend itself necessarily to either consideration of technical spillover on parties not directly involved or to consideration of the broader long-term agro-ecosystem effect. Nor is it likely that farmers will consider the effect of a particular decision on pest resistance in the future or on the devel opment of secondary pests. In this commercial-agricultural con text, biological and culturaLcontrols are faced with two major problems. To apply biological and many cultural methods requires an understanding of the basic biology of the pest, including its life cycle and its natural enemies. This, Headley points out, is a time-consuming and ex pensive capital investment process. Also, marketing and distribution offer problems. It is possible, for example, to rear and sell natural enemies—and in fact, Headley notes, this is already being Headley notes four problems with pest done. But much of what is involved in Much has been said in recent years about the need to modify the pest-control control in modern agriculture: test resis biological and cultural methods is devel strategy of agriculture based principally tance developed in response to previously opment of information. And the eco on the use of chemicals. But not much is used chemicals, secondary pests that have nomics of commercial information is likely to happen in the near future with risen with reductions in beneficial species complicated by problems of maintaining out a change in the institutional frame as a result of using wide-spectrum pesti proprietary control so that the developer cides, hazards to farm workers and others can get the economic return necessary for work of agriculture, according to agricul tural economist J. C. Headley of the arising from acute or chronic toxicity of its generation. some chemical pesticides, and hazards to University of Missouri, Columbia. Consequently, Headley says, there Because of imperfections of markets, nontarget species such as fish and birds. won't be any rapid change in current Alternatives to complete reliance on pest-control strategy. To gauge the out individualistic competition in production chemical pesticides include biological and look, Headley surveyed a group of agri agriculture will not produce a socially acceptable level or kind of pest control, cultural controls. The concept of inte cultural experts in extension and research. grated pest control came along about 10 Their conclusions were that chemicals will Headley told the American Association years ago. This approach would use a mix continue to be of major importance, with for the Advancement of Science meeting in Houston. Some method must be found, of chemical, biological, and cultural con use of insecticides declining and use of he says, to adjust for the external effects trols. Chemicals, Headley points out, are herbicides increasing. A technology as most effective in quickly reducing soaring sessment by Midwest Research Institute of chemical pesticides use and to adjust has come to the same general conclusions, pest populations. for short-term planning goals inherent in making pest-control decisions. But the institutional structure of agri Headley says. Headley believes there is a need for expanding the role that the public at large plays in development and application of Chemicals to continue major role in pest control pest control to agriculture. More R&D in pest control needs to be done, he says, Probable use to 1992 Trend in use Pest control technique particularly by the agricultural colleges, Chemical methods which are close to the farmer. Also, in Declining Insecticides Major developing selective chemicals necessary Increasing Major Herbicides for use in biological methods, policies are Minor Declining Mechanical methods needed to provide for franchising private concerns to produce and market chemi Biological methods cals developed with public funds. Minor No change Parasites & predators At the farm level, Headley suggests increasing Minor Bacteria establishing pest control districts, perhaps Increasing Not significant Viruses conforming to counties. Coupling these Not significant No change Pheromones with a scheme of crop insurance, he says, increasing Major Resistant varieties could provide a setting in which pestMinor Declining Pest genetics control decisions could be made that Cultural methods consider both external effects and Declining Minor Crop rotations longer-term concern for ecological sta Minor No change Trap crops bility. At the same time, individual farmers would be protected from any Note: Estimates of importance of pest control methods i grain crops and soybeans In U.S. agriculture 1978-92 by adverse effect the decisions might have on 39 U.S. agricultural extension and research workers. them. Π
disadvantage is that some key factor other than those used for comparison may be different in the compared areas. In fact, Gehman says, success or failure of analog methods probably depends more on dif ferences than on similarities. Another method is the Delphi ap proach, which takes the average of several expert opinions of the probability distri bution of potential resources. Still other methods involve areal and volumetric yields, geochemical yields, field numbers and sizes, summations of assessments of smaller areas, and extrapolation of dis covery rates. Analyzing the various geologic controls of hydrocarbon existence, Parker em phasizes the difficulties in making quan titative predrill estimates. Paradoxically, he notes, the more dry holes drilled, the better the chances of finding more of the oil that remains to be found, since addi tions are being made* to the data base. An example of the difficulty, Parker says, is the experience in the overthrust belt of Montana, Idaho, Wyoming, and Utah, where a spectacular series of dis coveries has been made. Four and a half
years ago, he notes, the U.S. Geological Survey estimated that the amount of oil and gas that might be found in the overthrust area would be minimal. There would be less than 1 billion bbl of oil and less than 1 trillion cu ft of gas. A year and a half ago, the Geological Survey's probability mean estimate of undiscovered recoverable oil and gas re sources in the central part of the IdahoWyoming thrust belt was 1.5 billion bbl of oil and 2.3 trillion cu ft of gas. There was a 5% probability that there would be 3 billion bbl of oil and 12 trillion cu ft of gas undiscovered and recoverable. Three months ago, Parker notes, industry geol ogists estimated a probability mean po tential for the entire Montana, Idaho, Wyoming, and Utah overthrust area of 17 billion bbl of oil and condensate and 95 trillion cu ft of gas. Thus, he says, the addition of data points and discoveries for geologists to work with has resulted, in 15 months, in a much larger area considered highly productive, an 11-fold increase in a "most likely" number for oil and condensate, and a 13-fold rise in gas potential. G
Chemicals remain strong in pest control
26
C&ENJan. 15, 1979
