pesticide takes 11 years and can cost manufacturers between $50 and $70 million (Ollinger and Fernandez-Cornejo, 1995). Results of a study of the impact of pesticide product regulation on innovation and the market structure in the U.S. pesticide industry indicate that regulation encourages the development of less toxic pesticide materials but discourages new chemical registrations, encourages firms to abandon pesticide registrations for minor crops, and favors large firms over smaller ones. Pesticide regulation also encourages firms to develop biological pesticides as an alternative to chemical pesticides (Ollinger and Fernandez-Cornejo, 1995). States are also active in regulating pesticide use. In 1996, most States had some regulations related to pesticide use in agriculture and/or lawn care, and over half have groundwater laws, posting requirements, and pesticide reporting regulations (Meister Publishing, 1996). Over a third of the States had health advisory levels, containment regulations, and bulk chemical regulations, and 13 States had requirements for reporting pesticide illnesses. The majority of States also have pesticide registration fees, many of which have increased in the last several years. Nine States tax pesticide products or have other special taxes (Meister Publishing, 1996) that have been used to fund research on pesticide alternatives. For example, the Leopold Center for Sustainable Agriculture, which conducts research on environmentally friendly alternatives, is partially supported from a tax on pesticide and fertilizer sales. Pesticide Registrations The EPA registration process requires manufacturers to provide scientific data to substantiate that a proposed product is safe and poses no unreasonable adverse effects to human health or the environment. Tests pertaining to toxicology, reproduction disorders and abnormalities, and potential for tumors from exposure to the pesticide are required. Other required tests evaluate the effect of pesticides on aquatic systems and wildlife, farm worker health, and the environment. The registration process can require up to 70 different types of tests to substantiate the safety of the product. Since 1989, the number of pesticide active ingredients for sale in the United States has decreased by 50 percent and further declines are expected due to reregistration requirements and costs (Pease and others, 1996). The recently enacted Food Quality Protection Act of 1996 requires periodic re-evaluation of pesticide registrations to ensure that the scientific data supporting registrations remain current. The new law mandates a screening program for estrogenic and other endocrine or synergistic effects and sets a goal for all pesticides to be reviewed and updated on a 15-year cycle. The registration and re-registration process also prescribes those commodities on which the pesticides can be used, at what concentration they can be applied, when and how they are to be applied, and what safety precautions are to be used during and after application. Table 3.2.7 identifies some of the key regulatory action taken against agricultural pesticides and gives the status of special reviews being conducted for reregistration. The EPA is currently conducting a special review of triazine herbicides (atrazine, cyanazine, and simazine). In 1995, the manufacturers of cyanazine voluntarily withdrew its registration rather than proceed with the special review. Cyanazine, which is identified as a carcinogenic material, is the third most used herbicide on corn and cotton and is also commonly used on sorghum and other crops to control grasses and broadleaf weeds. The manufacturer has agreed to stop selling products containing cyanazine by 1999. Mevinphos and propargite are insecticides that have been voluntarily canceled by their manufacturers. Mevinphos was canceled for all uses in 1994 due to concerns about acute toxicity and farmworker safety. Because this pesticide degrades quickly after application, it requires only a short interval before harvesting. It was used for aphid control on many fresh fruits and vegetables late in the growing season when other agents could not be applied. Propargite was withdrawn in early 1996 due to concern about residues on fresh market produce and possible exposure to infants and children. It was canceled for use on apples, apricots, cranberries, figs, green beans, lima beans, peaches, pears, plums, and strawberries. In 1993, regulatory action was taken for methyl bromide under the Clean Air Act because of its adverse affect on the ozone layer in the upper atmosphere. Production and use will be terminated in 2001 and annual production until that date is limited to the 1991 level. Pesticide Resistance Pesticide resistance is most likely to develop when a pesticide with a single mode of action is used over and over in the absence of any other management measures to control a specific pest. If a weed, insect, or fungi species contains an extremely low number of biotypes resistant to the killing mode of the pesticide, Table 3.2.7-EPA regulatory actions and special review status on selected pesticides used in field crops production, 1972 - June 1995 Pesticide Alachlor Aldicarb Aldrin Captafol Chlordimeform Cyanazine DDT Diazinon Dimethoate Dinoseb EBDC (Mancozeb, Maneb, Metiram, Nabam, Zineb) Endrin ΕΡΝ Ethalfluralin Heptachlor Linuron Methyl Bromide Mevinphos Monocrotophos Parathion Propargite Toxaphene Trifluralin 2,4-D (2,4-DB, 2,4-DP) Regulatory action and date Uses restricted and label warning, 1987; under EPA review for groundwater contamination Use canceled on bananas, posing dietary risk, 1992 All uses canceled except for termite control, 1972 All uses canceled, 1987 All uses canceled, 1988. Use of existing inventory until 1989 Manufacturers voluntarily phasing out production by 2000 but stock can be used until 2003 All uses canceled except control of vector diseases, health quarantine, and body lice, 1972 Dust formulation denied and label changed, 1981 All uses canceled, 1989 Protective clothing and wildlife hazard warning, 1982 All uses canceled, 1985 All uses canceled, 1987 Benefits exceeded risks, additional data required, 1985 All uses canceled except homeowner termite product, 1988 No regulatory action needed, 1989 Annual production and use limited to 1991 levels with use to be terminated in 2001, 1993 Voluntary cancellation of all uses, 1994 All uses canceled, 1988 Use on field crops only, 1991; under EPA review with toxicological data requested Registered use for 10 crops canceled, 1996. Use for other crops remains legal Most uses canceled except emergency use for corn, cotton, and small grains for specific insect infestation, 1982 Industry agreed to reduce exposure through label change and user education, 1992 Source: USDA, ERS, based on information in EPA, 1995. then those species that survive the pesticide treatment reproduce future generations containing the pesticide resistant trait. As this process repeats, the resistance trait multiplies and begins to account for a significant share of the species' population. Although herbicide-resistant weeds have been documented since the early 1950's, their prominence in the last two decades has increased, resulting in management strategies that seek to minimize development of pesticide-resistant species. Rotating pesticides with different modes of action, applying mixtures of-herbicides, reducing application rates, and combining mechanical or nonchemical control practices are some management strategies to reduce pesticide resistance (Meister Publishing, 1966). Resistance to triazine herbicides (atrazine, cyanazine, and simazine) is one of the more common weed-resistant problems in corn and sorghum. Farmers responding to USDA's Cropping Practices Survey in 1994 reported that 16 percent of the corn acreage had triazine-resistant weeds. To deter these and other weed resistance problems, producers reported that they alternated herbicides on the majority of corn, soybean, and cotton acreage. In recent years, producers also have reported using different active ingredients on each treated acre and lowering the application rates, both practices prescribed to deter herbicide resistance. Similar to the development of weeds resistant to herbicides, the incidence of insects, mites, and disease-causing fungi species resistant to pesticides also causes producers to switch to different chemicals or pest controls (NRC, 1986). Once insect or fungi species develop resistance to one ingredient, the time required to develop resistance to other ingredients of the same chemical family is often much less. Over a short period of time, species resistant to an entire family of ingredients can develop and require a different mode of treatment. At least partially due to development of insecticide resistance, cotton insecticide families shifted from mostly organochlorines prior to the 1970's to organophosphates and carbamates and more recently to synthetic pyrethroids (Benbrook, 1996). Scouting to determine economic thresholds for treatments, alternating the use of pesticide families, and several other management strategies to combat resistance are now in use (see chapter 4.4, Pest Management). New Pest Control Products and Technology Each year, the EPA registers several new pesticides which producers may adopt if they offer improved pest control and are profitable. Acetachlor was granted conditional registration in 1994 as an herbicide for use on corn that would help reduce overall herbicide usage. The registration allows automatic cancellation if the use of other herbicide products is not reduced or if acetachlor is found in ground water. In 1995, about 23 million pounds of the new product were applied to 20 percent of U.S. corn acreage (table 3.2.3). The reduced pounds of alternative herbicides (alachlor, metolachlor, atrazine, EPTC, butylate, and 2,4-D) more than offset the pounds of acetachlor. Other pesticide products have significantly affected the quantity of total use. For example, Imazethapyr, first registered for use on soybeans in 1989, has become the most widely used soybean herbicide in the United States. This herbicide, applied at less than 1 ounce per acre, often replaced trifluralin and other older products, applied at rates many times higher than imazethapyr. Transgenic corn and cotton seeds have been marketed recently in the hope of reducing the need to apply insecticides. These seeds were bioengineered to produce Bt, a bacterial insecticide that can control cotton bollworms, European corn borer, and other insects when they eat plant tissues containing the Bt bacteria. Some scientists are concerned that the plants do not produce sufficient levels of pesticides and that the pest survival rates will speed up the evolution of pest resistance to Bt, including Bt sprays. Resistance management plans are often prescribed when these products are adopted (Science, 1996). About 13 percent of the U.S. cotton acreage was reported planted with this transgenic cotton seed in 1996. Bt, as a spray insecticide, was applied to 9 percent of the 1995 cotton acres, but only 1 percent of the corn acres. Author: Merritt Padgitt, (202) 219-0433 References Aspelin, A. (1994). Pesticide Industry Sales and Usage: 1992 and 1993 Market Estimates. Biological and Economic Analysis Division, Office of Pesticide Programs, US EPA, 733-K-94-001. Benbrook, C.M. (1996). Pest Management at the Cross roads. Consumers Union, Yonkers, New York. p. 51. Callahan, R. (1994). "The ABCs of Industry Regulations," Farm Chemicals. pp. 113-118. DiTomaso, J.M., and D.L. Linscott. (1991). "The nature, modes of action, and toxicity of herbicides," in The Handbook of Pest Management in Agriculture, Vol II, ed. David Pimentel (2nd edition) CRC Press: Boca Raton, 523-569. pp. Dyer, W.E., F.D. Hess, J.S. Holt, and S.O. Duke. (1993). "Potential Benefits and Risks of Herbicide-Resistant Crops Produced by Biotechnology," Horticultural Reviews, Vol 15, pp 367-399. Fernandez-Cornejo, J. (1992). "Short- and Long-run Demand and Substitution of Agricultural Inputs," Northeastern Journal of Agriculture and Resource Economics, 21:36-49. Gianessi, L.P., and J.E. Anderson (Feb. 1995). "Pesticide Use in U.S. Crop Production: A National Summary," National Center for Food and Agricultural Policy, Washington, D.C. Gianessi, L.P., and J.E. Anderson (1995). "Potential Impacts of Delaney Clause Implementation on U.S Agriculture." National Center for Food and Agricultural Policy, Washington, D.C., TR-95-1. June. Kovach, J., C. Petzoldt, J. Degni, and J.Tette (1992). "A Method to Measure the Environmental Impact of Pesticides," New York's Food and Life Sciences Bulletin, No. 139. Kuchler, F., K. Ralson, L. Unnevehr, and R. Chandran (1996). Pesticide Residues, Reducing Dietary Risk. AER-728. U.S. Dept. Agr., Econ. Res. Serv. Levitan, L., I. Merwin, and J. Kovack (1995). "Assessing the Relative Environmental Impacts of Agricultural Pesticides: The Quest for a Holistic Method," Agriculture, Ecosystems, and Environment, 55, pp. 153-168. Lin, B., M. Padgitt, L. Bull, H. Delvo, D. Shank, and H. Tay- McIntosh, C.S., and A.A. Williams (1992). "Multiproduct Production Choices and Pesticide Regulation in Geor Glossary Acute Risk Indicator—An indicator of the potential human and environmental health risk from an acute exposure to pesticides. An indicator value equal to 1 is the presence of 1 LD50 dose in the environment for 1 day. (See box, "Estimating Pesticide Impact or Risk," p. 124) Amount of pesticide applied is the total pounds of all pesticide active ingredient (excluding carrier materials) applied. Because this sum can include materials applied at very different rates, differences in the amount applied do not necessarily represent differences in the intensity of the treatment or potential health and environmental risks. Chronic Risk Indicator—An indicator of the potential human health risk from a chronic exposure to pesticides. An indicator value equal to 1 is the presence of 1 Reference Dose in the environment for 1 day. LD50 dose-The constructed measure reflects the pesticide dose level (mg/kg of body weight) which results in 50 percent mortality of laboratory test animals. The LD50 values used in constructing the acute risk indicator relate to ingestion of the active ingredient (Oral LD50). Land receiving pesticides represents an area treated one or more times with a pesticide material. Pesticide materials include products used to kill weed, plant, and fungi pests, as well as products used as growth regulators, soil fumigants, desiccants, and harvest aids. Number of acre-treatments applied represents total number of ingredients applications made throughout the growing season. A single treatment containing two ingredients is counted as 2 acre-treatments as is 2 treatments containing a single ingredient. Number of ingredients applied represents the total number of different active ingredients applied throughout the growing season on a field. It does not reflect repeat applications of the same ingredient during the production year. Number of treatments applied represents the number of application passes made over a field to apply pesticides. One or more pesticide materials may be applied with each treatment. This measurement reflects labor and pesticide application equipment usage. Pesticide, according to the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA), is "... any substance or mixture of substances intended for preventing, destroying, repelling or mitigating any insects, rodents, nematodes, fungi, or weeds, or any other forms of life declared to be pests; and any substance or mixture of substances intended for use as a plant regulator, defoliant, or desiccant." Types or classes of pesticides are: Fungicides-Control plant diseases and molds that either kill plants by invading plant tissues or cause rotting and other damage to the fruit before and after it can be harvested. • Herbicides Control weeds which compete for water, nutrients, and sunlight and reduce crop yields. Herbicides that are applied before weeds emerge are referred to preemergence herbicides. Preemergence herbicides have been the foundation of row crop weed control for the past 30 years. Herbicides applied after weeds emerge are referred to as postemergence herbicides. Postemergence herbicides are sometimes considered more environmentally sound than preemergence herbicides because they normally have little or no soil residual activity. Treatments applied prior to any tillage or planting to kill existing vegetation are referred to as burndown applications. Burndown applications are often a part of no-till systems. • Insecticides-Control insects that damage crops. Also include materials used to control mites and nematodes. • Other Pesticides-Include soil fumigants, growth regulators, desiccants, and other pesticide materials not otherwise classified. Reference Dose-The constructed measure reflects the long-term safety/toxicity of pesticides to humans. It is measured as the no-observable-effect level of a pesticide ingredient multiplied by an uncertainty factor, which adds an additional safety factor in translating animal no-observable-effect levels to human no-observable-effect levels. The constructed value represents the "dose" (mg./lb. of body weight) which could be consumed daily over a 70-year life span by a person weighing 70 kg. without having adverse health effects. |