entom 558 pesticide topics fall 2005 october 31, 2005 lecturer: … · 2007-05-10 · regulatory...

ENTOM 558 Pesticide Topics Fall 2005

ENTOM558 Lect 103105 Benefits Regs.doc of 29

October 31, 2005 Lecturer: Allan Felsot, Department of Entomology, Food & Environmental Quality Lab, WSU-

TriCities Campus, [email protected] Pesticide Benefits & Costs; Pesticide Regulation—Evolution of Laws; Food Quality Protection Act Overview Part 1: A Consideration of Pesticide Benefits and Utility I. Introduction

A. Any consideration of pesticide regulations will be better informed by first considering the question, “Why Use Pesticides?” 1. Indeed, listening and reading to certain advocacy groups, one would think that crop

protection was a simple matter for which there was already available an “off-the-shelf” non-pesticide technology. a. However, such a simplistic, black-or-white notion belies the complexity of any

agroecosystem. b. Furthermore, the goal of crop protection seems to have moved from ecological

management (i.e., reduce competition between pests and humans) to “eliminate pesticide use.”

2. In developed countries, the focus is on agricultural pests and pesticides, perhaps because they seemed to have public health pests tamed. Yet, in many countries, public health pests are the major threat, and the context of “why use a pesticide” takes on a different meaning.

II. Definitions A. Before considering why pesticide use may or may not be indispensable, consider the

regulatory definition of a pesticide and how it differs from fertilizers. B. Fertilizer

1. Macro and trace nutrients added to soil, or in some cases to plant foliage, to maximize the production of plants (crop, ornamentals, lawns, etc.)

2. Not regulated by EPA with regards to labeling requirements or application rates; requires no permits or licenses to make an application; a. However, consequences of use of any fertilizer as it pertains to effects on water

quality will be under the jurisdiction of the EPA through both the Safe Drinking Water Act and the Clean Water Act.

3. States may regulate labeling of fertilizers to protect against adulteration, which can include putting in too much or too little of a nutrient; a. Canada regulates the heavy metal content of fertilizers in addition to the essential

elements. b. WA State now has regulations for maximum permissible heavy metal content,

modeled after the Canadian standards C. Pesticide (defined by law--the Federal Insecticide, Fungicide, and Rodenticide Act

(FIFRA), passed 1947, Title 40 CFR (Code of Federal Regulations, Section 162.3): 1. Any substance or mixture of substances intended for preventing, destroying,

repelling, or mitigating any pest (insect, rodent, plant or animal life or viruses,



bacteria, or other microorganisms, except viruses, bacteria, or other microorganisms, on or in living man or other animals, which the Administrator declares to be a pest); in other words, a pest is: a. Any insect, rodent, nematode, fungus, weed, or b. Any other form of terrestrial plant or animal life or virus, bacteria or other

microorganism (except viruses, bacteria, or other micro-organisms on or in living man or other living animals), which the [EPA] administrator declares to be a pest.

2. Any substance or mixture of substances intended for use as a plant regulator, defoliant, or desiccant;

3. Definition in (1), therefore does include disinfectants; a. Indeed, if you look on a can of Lysol, you will see the active ingredient (the older

cans contained orthophenylphenol) with an EPA Registration No. (which must accompany all approved pesticide active ingredients).

4. The major groups thus include herbicides, insecticides (also acaricides & nematicides), fungicides, plant growth regulators, rodenticides, molluscicides, piscicides, and disinfectants. a. Note that pesticides generally have several nomenclatural designations;

1. Common chemical name (the technical active ingredient) a. endosulfan (MW = 406.9)

2. Formulation names containing the active ingredient (commercial product) a. Thiodan, Thiofur, and others

3. Official” chemical nomenclature (i.e., approved by the IUPAC--International Union of Pure and Applied Chemistry)

1. a. 6,7,8,910,10-hexachloro-1,5,5a,6,9,9a-hexahydro-6,9-methano-2,4,3-benzodioxathiepin 3 oxide (HOLY COW!!)

III. The Rationale for Use of Agrichemical Technology Lies in the Nature of

Agroecosystems and Associated Pests A. Natural ecosystems are self-sustaining by virtue of their biotic diversity, naturally

adapted to the physical environment; such diversity allows the system to respond to perturbations. Furthermore, the soil stores plant nutrients, which are continually recycled throughout the ecosystem. 1. For example, the ecosystems around Mt. St. Helen have been re-establishing because

of the inherent genetic diversity that was present in the system. B. Agroecosystems have significantly less diversity, therefore they cannot adapt easily (i.e.,

economically) to perturbations in the system. 1. Keep in mind that agroecosystems are designed to maximize profit for the grower,

thus many systems are monocultures or bicultures (for example, strip farming, where crops are grown in alternating rows of variable number). Thus, agroecosystems are designed to have less diversity. a. Row crops and vegetable crops are disturbed at least annually; b. Fruit crops are disturbed very infrequently, unless the areas between

trees/bushes/vines are cultivated. 2. It is easier for one species to become dominant and overwhelm other organisms in the

system.



3. Modern cropping systems tend to be monocultures with very limited genetic diversity; therefore, they are very susceptible to perturbations by organisms that use the crop as a food source.

4. Nutrients are continually removed from the system by the annual harvesting of plant material.

C. Pests can be native to ecosystems that have been altered to grow crops or they can be incidentally imported from other continents 1. In the first case, the pest has a readily abundant food supply and its population will

grow quite readily, especially if mortality factors do not adequately suppress its population. a. Mortality factors include natural enemies (predators and parasitoids), diseases,

adverse meteorological conditions, starvation) b. An example of a native pest is the northern corn rootworm, which feeds on the

roots of corn grown in the northern tier of the Corn Belt. 2. In the second case, natural mortality factors, especially that related to natural

enemies, may not be present or operational in the new ecosystems to which the immigrant organism has arrived; thus immigrant (or exotic) organisms easily become established (for example, the Gypsy moth attacking forests of the northeast; the Colorado potato beetle, attacking potatoes grown just about everywhere in the U.S.)

IV. The Nature of Agroecosystems (and Human Objectives) Demand Some Form of

Management (Intervention) A. The conflict between the economic value of a crop and its susceptibility to damage from

a burgeoning pest population demands the need for management of both the crop and the pest.

B. The continual removal of nutrients from the soil by harvesting a crop (i.e.) and the comparatively short time interval between successive cropping needs demands the addition of readily available nutrients to grow succeeding crops.

C. The intentional addition of fertilizers and pesticides to cropping systems has been occurring for hundreds of years, suggesting that ecosystem management is not a recent cultural attribute. 1. History of Pesticides (reference: G. W. Ware (1983), Pesticides: Theory &

Application, W. H. Freeman & Co., San Francisco, pp. 11-13)--some notable highlights: a. 1200 BC: biblical armies salt and ash the fields of the conquered; first reported

use of nonselective herbicides? b. 1000 BC: Homer refers to sulfur used in fumigation and other forms of pest

control; c. 100 BC: The Romans apply hellebore (lily family, contains alkaloids) for the

control of rats, mice, and insects; d. 70 AD: Pliny the Elder reports pest control practices from Greek literature of the

preceding three centuries; for ex.: 1. Touch the top of an apple tree with the gall of a green lizard for protection

against caterpillars and rot! e. 900 AD: Chinese use arsenic to control garden insects; f. 1690 AD: Tobacco extracts used as contact insecticide



g. 1787 AD: Soap mentioned as insecticide; turpentine emulsion recommended to kill and repel insects;

h. 1800 AD: Persian louse powder (actually pyrethrum) known to the Caucasus; sprays of lime and sulfur recommended in insect control; whale oil recommended for scale insect control;

i. 1848 AD: Derris (rotenone) reported being used in insect control in Asia; j. 1867 AD: Paris green (aceto-meta-arsenite of copper)

1. First used as a green pigment in paints, fabric and wall paper; 2. Used in Colorado potato beetle control and mosquito control.

k. 1892 AD: Lead arsenate first prepared and used to control gypsy moth; first use of a dinitrophenol compound as an insecticide (dinitrophenols are uncouplers of oxidative phosphorylation).

2. Thus, fertilizers and pesticides are intentionally added (and always have been added) to agroecosystems (or urban environments) to replace elements or processes that would function in natural ecosystems but are absent from agroecosystems.

V. Role of Agricultural Chemicals in Crop Production & Protection

A. Prior to considering the specific benefits of pesticides and fertilizers, consider farmland utilization and production changes relative to population changes after World War II (Figure 1).

Figure 1. Trends through 1960 in crop production, acreage for production, and population

growth.

crop

productionindex

crop acresharvested

farm acres

population



B. Consider the estimated amounts of crop losses despite the use of pesticides. 1. Estimates of losses due to plant diseases in North and Central America combined in

1987 were 11.3% of crop production at a cost of $14 billion (James et al. 1991). a. The total cost of fungicides for controlling diseases was estimated as 3% of the

total loss due to disease. 2. An annual economic loss due to weeds was estimated as $9 billion during 1975-1979

(Chandler 1991). C. Benefits of Pesticides & Fertilizers

1. Until August 1996, the benefits of pesticides were permitted consideration. FIFRA (Federal Insecticide & Fungicide Act), the main statute governing pesticide technology (along with the Federal Food, Drug, and Cosmetic Act, FFDCA) had been the only environmental law governing chemical technology allowing an assessment or balancing of the benefits and risks; a. During August 1996, FIFRA and FFDCA were amended by the Food Quality

Protection Act (FQPA). The FQPA severely restricted consideration of benefits when registering a pesticide (discussed below).

2. The use of pesticides and fertilizers can be empirically be shown to be correlated with yield increases a. During 1951-1960, insects caused an estimated annual loss worth $6.8 billion

(cited in Hayes and Laws 1991, Handbook of Pesticide Toxicology, vol. 1, General Principles, Academic Press, Inc.) 1. Note in the graph below (Figure 2) that corn yield jumped with the use of

hybrid seed, but really took off once fertilizer and later insecticide use increased (graph copied from Hayes & Laws 1991).

corn yield

Hybrid

Seed Use

fertilizer

insecticide



Figure 2. Trend in corn yield in relationship to hybrid seed, fertilizer, and insecticide use.

b. Weeds caused average losses of 22-44% of production of soybeans, corn, small

grain, flax, and forage compared with weed-free or weed-controlled fields of the same crops (MN Agric. Extension Service 1964 as cited in Hayes & Laws 1991)

(see Figure 3) Figure 3. Yield of corn and soybeans are affected by weed density.

3. Pesticides also play a major role in protection of human health; for example, the

control of malaria or other insect-vectored diseases (Figure 4). a. In India during 1933-35, there were 100 million cases of malaria; in 1966 (long

after the use of DDT began), there were 150 thousand cases (translated to dollars, this was a change from a 1.3 billion dollar economic loss to a $2 million dollar loss) (from Hayes & Laws 1991).

Effect of Weeds on

the Production of Corn and Soybeans

Corn

Soybeans



Figure 4. Effect of the DDT spraying campaign in India on Anopheline mosquito population and incidence of malaria.

4. More recent economic analyses for crops grown in California show significant income losses when pesticides are banned (Zilberman et al. 1991) a. For example, the yearly cost to growers and consumers in banning use of

parathion on lettuce in California was calculated to be 48.4 million dollars (note: nonusers of parathion who grow lettuce actually gained because of higher prices, but consumers still lose).

5. An economic analysis based partly on stakeholder surveys and modeling predicted significant losses in vegetable and fruit production if pesticide use was reduced either by 50% or completely eliminated (Knutson et al., 1993) (Figure 5).

6. Another economic analysis (Taylor 1995) estimated per acre-yield decreases of 25% and 60% for respectively, 50% and 100% pesticide use reduction. The corresponding costs of production were estimated to increase by 30% and 75%, for 50% and 100% pesticide elimination, respectively. The wholesale price increase estimates varied by

Anophelinemosquitoes/month

from capturing

stations

Malaria cases/1000

inhabitants

DDT Spraying Post 1945



commodity, ranging from 9-19% for a 50% pesticide reduction scenario and from 29-65% for a 100% elimination. Also, domestic use of fruit and vegetables were estimated to decline by 4%-7% (50% reduction) or 7%-23% (for 100% elimination). With a total ban on pesticides, acreage required for production of fruit and vegetables was estimated to increase by 2.5 million acres.

Figure 5. Estimated loss in yield for two pesticide use scenarios, 50% reduction and

zero use.

D. Pesticides have certain advantages in crop protection that make their use very convenient, efficient, and cost-effective (i.e., the number one tool in crop protection) (from Metcalf & Luckmann, 1975) 1. For most cropping systems and in some cases insect-vectored diseases, pesticides are

the only practical technology (i.e., other technologies are not available, unproved, or do not work efficiently)

2. Pesticides have rapid curative action in preventing loss of crop yield or protecting human/animal health a. Thus, they can be used in an emergency; b. Furthermore modern pesticides are biodegradable; thus, they disappear from the

agroecosystem (at least the residues become toxicologically insignificant--a point of some controversy)

3. Pesticides offer a wide range of properties, uses, and methods of application to pest situations a. Many different types of products (chemistry); some selective, some broad

spectrum; b. Many modes of application and formulations available

4. Economic return-cost ratio for pesticide use is generally favorable



a. Depending on the crop, this ratio can range from $4-$29 returned for every $1 spent.

b. The economic return-cost ratio goes down when 1. Price of crop decreases but pesticide cost is fixed; 2. A product is used and pest populations are not at a level that will cause

economic damage 3. Development costs for a new product are high

E. Given the benefits and advantages of pesticides, have we been suckered into some kind of treadmill? 1. Costs of Pesticide Development and Registration

a. R&D costs have been estimated to be over $70 million. 1. Furthermore, once the pesticide has been discovered and the required tests

conducted, EPA may require 24-38 months to review the request for registration (Racke 2003)

b. Reregistration Fee estimated at $150,000 per product (i.e., not active ingredient but formulated product); does not include cost of any new studies that may be required

c. Product maintenance fee estimated at $35,000 d. Economics of pesticide development and marketing (Leng 1991)

1. It may take 15 years from discovery for a pesticide product to attain a positive cash flow; by year 20 after discovery, the patent would have expired (the patent is usually obtained around 3 years after discovery of a new product)

2. Has pesticide use shot up (as one might predict if we were on a treadmill)? a. Generalizations are dangerous!!

1. There is a tendency to equate the amount of pesticide use with hazard, but these are not evenly remotely related if once considers basic toxicological and risk assessment principles. a. For example, the most heavily used pesticide in orchard crops are

petroleum oils, largely used as a dormant spray for insect control. These same compounds are certified for organic agriculture, and they are even used for post bloom control of pests in organic orchards.

b. Amounts of pesticides used will vary depending on acreage cropped, weather, and pest outbreaks.

c. For trends in pesticide use over the last decade, specifically for field crops (corn, cotton, potatoes, rice, soybeans, and wheat) and various fruit and vegetable crops, see the NASS (National Agricultural Statistical Service) web site (http://usda.mannlib.cornell.edu/reports/nassr/other/pcu-bb/). (see Table 1 for selected statistics)

d. The impact of transgenic characters for pest control, for example, Bt toxin containing corn and cotton and Round-Ready crops, remains to be seen, but preliminary data indicate that less insecticides are being used in cotton. Overall use of herbicides may be down in soybeans, but the trend was going down owing to the use of low-rate herbicides.



Table 1. Change in acreage and pesticide use for corn, potato, and apple (1991 vs. 2003) (Data are taken from the USDA National Agricultural Statistical Service Reports, URL: http://usda.mannlib.cornell.edu/reports/nassr/other/pcu-bb/

Corn 1991 2003 Change Acres Planted X 106 76.2 72.7 -3.51 % Acres Treated with Herbicides 94 95 1 Pounds X 106 211 149 -62 % Acres Treated with Insecticides 30 29 -1 Pounds X 106 23.3 7.47 -15.83 Potato 1991 2003 Change Acres Planted X 106 1.20 1.02 -0.18 % Acres Treated with Herbicides 79 91 12 Pounds X 106 2.2 1.58 -0.62 % Acres Treated with Insecticides 91 84 -7 Pounds X 106 3.1 1.57 -1.53 % Acres Treated with Fungicide 69 91 22 Pounds x 106 2.7 6.54 3.84 % Acres Treated with Others (Fumigants, Defoliants) 45 47 2 Pounds x 106 39 75.4 36.4 Apple 1991 2003 Change Acres Planted X 106 0.35 0.305 -0.045 % Acres Treated with Herbicides 42 42 0 Pounds X 106 0.31 0.386 0.076 % Acres Treated with Insecticides 99 94 5 Pounds X 106 12.7 9.3 -3.4 % Acres Treated with Fungicide 83 90 7 Pounds x 106 4.7 4.86 0.16 % Acres Treated with Others (Plant Growth Regulators, Pheromones) 57 20 -37 Pounds x 106 0.07 0.134 0.064

VI. The Down Side of Pesticide Use

A. Despite their benefits, pesticides have limitations that make their indiscriminate use unwise 1. Noted Problems With Pesticides (note: the first three listings are considered by many

scientists to be the most important problems; the change in pesticide chemistry over the last two decades has demoted the importance of the last two listings, although these are still very controversial with regard to their significance)



a. Worker exposure and poisoning (especially acute toxicity) 1. Pesticide Incident Reporting and Tracking panel in WA State

b. Development of pest resistance; limits the available control technologies c. Reduction of natural enemies and resurgence of pest problems; elevation of

importance of damage by “secondary” pests d. Adverse effects on environmental health

1. Fish/bird kills 2. Bioaccumulation in food chain 3. Endocrine disruptive effects

e. Human health (general population) 1. Chronic toxicity (cancer) 2. Accidental or intentional acute poisoning

B. Calculating An Economic Cost (Environmental and Social Costs) to Pesticide Use 1. Total estimated environmental and social costs from pesticide in the U.S. (according

to Pimental et al. 1993) (Table 2).

Table 2. Estimated health, environmental, and social costs of pesticide use. Costs Million $ per Year Public health impacts 787 Domestic animals deaths and contamination 30 Loss of natural enemies 520 Cost of pesticide resistance 1400 Honeybee and pollination losses 320 Crop losses 942 fishery losses 24 Bird losses 2100 Groundwater contamination 1800 Government regulations to prevent damage 200 TOTAL 8123

VII. Reconciling Pesticide Use with Environmental Stewardship--The Advent of

Integrated Pest Management (IPM) and Sustainable Agriculture A. Not long after the widespread (and frequent) use of DDT, agricultural scientists realized

it was not the miracle cure for insect problems; this recognition led to the development of the concept of integrated control (now known as IPM). 1. Integrated control recognized that pest control was most efficient when biological

control (i.e., natural enemies) and cultural practices were integrated with chemical control; however, chemical control had to have certain characteristics to make it effective over the long-term and environmentally safe (Stern et al., 1959); a. Use of selective insecticides (i.e., high toxicity to pests, low toxicity to nontarget

organisms); 1. The ideal insecticide “is one that shifts the balance back in favor of the natural

enemies.” b. Treating only areas where the pest-natural enemy ratio is unfavorable (to

effectively managing the pest population);



c. Proper timing of insecticide application (apply only when pest population can cause economic loss; apply only when beneficial insects (like honeybees) are not foraging;

d. Use of rapidly degradable chemicals; e. Development of insect pathogens as insecticides.

B. One of the key aspects of the development of integrated control and the evolution of IPM was the acquisition of the fundamental knowledge of the ecology of the agroecosystem and a detailed analysis of the population dynamics and behaviors of the pests and the natural enemies. 1. Such knowledge leads to the development of economic injury levels and economic

thresholds. 2. In brief, for any population in an ecosystem, there are dynamic fluctuations in

population density over time, but there is a general equilibrium position about which these populations fluctuate (Figure 6). a. The economic injury level (EIL) is the pest population density causing sufficient

crop damage to prevent economic return from exceeding costs of production. b. The economic threshold (ET) is the pest population level at which control

measures would be implemented to prevent the population from reaching the economic injury level. Theoretically, at the ET the cost of control would equal the return from implementing the control.

Economic Injury Level (EIL)

Economic Threshold (ET)

Popula

toin

Density

Time

Insect Populations are Controlled by

Biotic and Environmental Factors

General

Equilibrium

Position (GEP)

Figure 6. Pest population dynamics in relation to the economic threshold and economic

injury level.

C. Essential Elements of Integrated Pest Management (defined as the practical manipulation of pest populations using sound ecological principles to keep the populations below the levels causing economic injury). 1. Insect bionomics

a. Must correctly identify (classify) the pest; such classification leads to a plethora of information about biology

2. Characterization of population dynamics



a. Development of life tables (identification of all the factors affecting mortality and the magnitude of the effects)

3. Development of scouting and sampling plans 4. Development of economic injury level and economic threshold 5. Development of alternative control options

a. Pesticides are only one tool, although for the vast majority of crops the most convenient and efficient; others include: 1. Biological control (introduction or encouragement of natural enemies) 2. Cultural control (for ex., crop rotation) 3. Mechanical control (for ex., powerful vacuum systems to suck up aphids;

weed cultivation) 4. Host plant resistance (physiological traits bred into plants that resist pest

damage) D. Ecologically Based Pest Management (EBPM)

1. A National Academy of Sciences report published in 1996 discussed the next evolution of IPM to EBPM;

2. The report argued that IPM systems were largely centered around synthetic pesticide use, but pest management needed to become more biologically centered.

E. The “Coming” of Sustainable Agriculture 1. Unfortunately, the term sustainable, especially as applied to agriculture, has become

confused with “no pesticide use”, but this is not even close to the intended meaning. It has also been misperceived as “big brotherism”--i.e., the government is going to tell farmers (who have been quite successful thus far) on how to farm or not farm. a. The term “sustainable” has become somewhat cliché; unfortunately there are no

models for sustainable systems; if past civilization were sustainable, they would still be here!! 1. Thus, we are engaged in a grand experiment. All we can do is continue to

learn how our universe works and develop technologies that seem consistent with long-term survival (not subsistence survival but survival with a high quality of life).

2. The best definition of sustainable agriculture is not a single definition at all but an operational definition (i.e., a set of circumstances or processes) (National Academy of Sciences 1993; preference for use of term alternative agriculture); thus alternative agriculture is any system of food or fiber production that systematically pursues the following goals: a. More thorough incorporation of natural processes such as nutrient cycles,

nitrogen fixation, and pest-predator relationships into the agricultural production process;

b. Reduction in the use of off-farm inputs with the greatest potential to harm the environment or the health of farmers and consumers;

c. Greater productive use of the biological and genetic potential of plant and animal species;

d. Improvement of the match between cropping patterns and the productive potential and physical limitations of agricultural lands to ensure long-term sustainability of current production levels;



e. Profitable and efficient production with emphasis on improved farm management and conservation of soil, water, energy, and biological resources

3. Some examples of practices and principles emphasized in alternative systems include: a. Crop rotations that mitigate weed, disease, insect, and other pest problems;

increase available soil nitrogen and reduce the need for purchased fertilizers; and in conjunction with conservation tillage practices, reduce soil erosion;

b. IPM, which reduces the need for pesticides by crop rotations, scouting, weather monitoring, use of resistant cultivars, timing of planting, and biological pest controls

c. Management systems to control weeds and improve plant health and the abilities of crops to resist insect pests and diseases;

d. Soil- and water-conserving tillage; e. Animal production systems that emphasize disease prevention through

health maintenance, thereby reducing the need for antibiotics; f. Genetic improvement of crops to resist insect pests and diseases and to use

nutrients more effectively. 4. Note most importantly that alternative systems are diversified; also it is not a

single system of farming practices; “it includes a spectrum of farming systems, ranging from organic systems that attempt to use no purchased synthetic chemical inputs, to those involving the prudent use of pesticides or antibiotics to control specific pest or diseases.”

F. To determine the potential role of an alternative system and whether or not it is sustainable, especially in an economic sense, it is helpful to analyze the whole system in terms of its energy costs and its yields per labor input costs; Pimental (1984) has done this for corn, wheat, and potatoes (comparing conventional with types of “organic systems) (Table 3).

Table 3. An energy analysis of conventional and organic agricultural production. System

Energy Efficiency (kcal output/kcal input)

Yield Per Labor Input (Mg output/labor hour)

Corn Conventional 4.47 0.834 Organic (manure fertilization)

7.34 0.535

Spring Wheat Conventional 2.38 0.422 Organic (manure fertilization)

3.49 0.314

Potato Conventional 1.28 0.943 Organic (manure fertilization)

1.20 0.367



1. Conventional systems were assumed to use pesticides and synthetic sources of

nutrients; equal fuel usage (i.e. gasoline, diesel, electricity) was assigned to each system

G. In conclusion, pesticide technology is here to stay, even with the coming of sustainable systems. But to be compatible, pesticides and fertilizer use must have certain environmental characteristics. Thus, we must study in detail the environmental chemistry and toxicology of these tools so that we can make improvements and allow their safe use over the long term.

VIII. References

Chandler, J. M. 1991. Estimated losses of crops to weeds. Estimated losses of crops from plant

pathogens. CRC Handbook of Pest Management in Agriculture, 2nd ed., vol. I. Pimentel, D., Ed. CRC Press, Inc., Boca Raton. Pp. 53-68..

Hayes, W. J., Jr., and E. R. Laws, Jr. 1991. Handbook of Pesticide Toxicology, vol. 1. Academic Press, Inc.

James, W. C., P. S. Teng, and F. W. Nutter. 1991. Estimated losses of crops from plant pathogens. CRC Handbook of Pest Management in Agriculture, 2nd ed., vol. I. Pimentel, D., Ed. CRC Press, Inc., Boca Raton. Pp. 15-51.

Knutson, R. D., C. R. Hall, E. G. Smith, S. D. Cotner, J. W. Miller. 1993. Economic impacts of reduced pesticide use on fruits and vegetables. American Farm Bureau Research Foundation. 123 pp.

Leng, M. L. 1991. Consequences of re-registration on existing pesticides. pp. 27-44 in “Regulation of Agrochemicals: A Driving Force in their Evolution, G. J. Marco, R. M. Hollingworth, and J. R. Plimmer, eds., Am. Chem. Soc., Washington, D.C.

Metcalf, R. L., and W. H. Luckmann. 1975. Introduction to insect pest management. John Wiley & Sons, N.Y.

National Research Council. 1989. Alternative Agriculture. National Academy Press, Washington, D. C.

Pimentel, D., G. Berardi, and S. Fast. 1984. Energy efficiencies of farming wheat, corn, and potatoes, organically. Organic Farming: Current Technology and its Role in a Sustainable Agriculture. American Society of Agronomy, Special Publication Number 46. pp. 151-161.

Pimentel, D., et al. 1993. Assessment of environmental and economic impacts of pesticide use. pp. 47-84 in “The Pesticide Question: Environment, Economics, and Ethics., Pimentel D. and H. Lehman, ed., Chapman & Hall, NY.

Racke, K. D. 2003. Development and registration of pesticides with reduced risk characteristics. Pp. 322-333 in “Chemistry of Crop Protection—Progress and Prospects in Science and Regulation”, G Voss, and G. Ramos, Ed. Wiley-VCH, Germany.

Stern, V. M., R. F. Smith, R. van den Bosch, and K. S. Hagen. 1959. The integrate control concept. Hilgardia 29:81-101.

Taylor, C. R. 1995. Economic impacts and environmental and food safety tradeoffs of pesticide use reduction on fruit and vegetables. The Department of Agricultural Economics and Rural Sociology, Auburn University, AL. 21 pp.



Ware, G. W. 1983. Pesticides: Theory & Application, W. H. Freeman & Co., San Francisco, pp. 11-13.

Zilberman, D., A. Schmitz, G. Casterline, E. Lichtenberg, J. B. Siebert. 1991. The economics of pesticide use and regulation. Science 253:518-522

Part 2. Pesticide Regulations IX. History of Pesticide Regulations (reference: Johnson, J. M., and G. W. Ware.

Pesticide Litigation manual. Clark Boardman Company, Ltd., New York.) A. Regulation of chemicals to protect the public from exposure has been traced back to the

mid-1800’s (~1863, “An Act for the More Effectual Condensation of Muriatic Acid in Alkali Works”) in England. In the U.S., the Pure Food & Drug Act (1906), the Meat Inspections Act (1906) and the Insecticide Act (1910) were early statutes aimed at chemicals and health concerns. 1. However, these acts really prevented consumer fraud and protected the legitimate

manufacturers of pesticides (originally called economic poisons) and drugs. 2. The Acts prevented the manufacture or transportation of adulterated or misbranded

pesticides and drugs within the United States or its territories. a. They did not provide for registration of products, nor testing requirements.

However, the Pure Food and Drug Act was intentioned to protect health. b. The Acts did require specific labeling information, namely it prohibited false or

misleading information on labels; The Insecticide act required specific label information for some categories of pesticides, i.e., those that contained arsenic (the amount had to be stated); furthermore, inert ingredients had to be stated. 1. Some recognition of environmental effects was contained in a provision that

stated a product was considered adulterated if it was intended for use on vegetables and yet proved to be injurious to those vegetables.

3. The Insecticide Act was little used; there were hardly any commercial pesticides available.

4. These acts were forerunners of respectively, the Federal, Food, Drug, and Cosmetic Act (FFDCA--1938), and the Federal Insecticide, Rodenticide, and Fungicide Act (FIFRA--1947)

B. The Pure Food and Drug Act and the Insecticide Act functioned in parallel to regulate pesticide products and in a rudimentary way protect human health from adulterated foods. 1. Both the Pure Food and Drug Act and the Insecticide Act had relied on designation of

products as misbranded or adulterated to keep inefficacious or undesirable products out of the market. a. An unanticipated issue raised by the Pure Food Act was determining when, or at

what level, treatment with a pesticide rendered a food product adulterated. b. There was an early recognition that pesticides could render a food unsafe, but

there was no mechanism for removing that food from the marketplace. 1. The Secretary of Agriculture, in order to prove that a food treated with a

pesticide was adulterated, had to prove the food was injurious to health. However, pesticide residues did not cause acute injury at the time.



a. Even today, residues that are above the so called tolerance or standards for legal sale are extremely unlikely to cause an acute, adverse response;

b. Furthermore, pesticides were recognized as being necessary to the production of crops.

2. Thus, the two acts were actually in conflict.

Pure Food & Drug Insecticide Act

Health Protection

Prohibit Misbranding and Adulteration

Ensure Efficacious Product

Adulteration Standard Placed the Laws in Conflict

Figure 7. Conflicting objective of the two original laws covering pesticide use.

c. To remedy the dilemma, the FFDCA (1938) provided that a food was adulterated if any amount of poisonous material (including pesticides) were present. However, a food was not considered adulterated by a pesticide if the pesticide was required for its production--thus was born the concept of benefit versus risk. In such a case, the Administrator of the Food and Drug Administration (FDA) was authorized to establish tolerances or legal (permissible) levels of pesticide residues. 1. Consider whether the state of the art of analytical chemistry would have even

been able to detect residues at this time. 2. The tolerances were supposed to be maximum legal residues; although they

were supposed to be developed to ensure safety, we will discuss how they are not really safety standards when we talk about how tolerances are developed in the lecture on food residues and dietary exposure.

d. The FFDCA was impractical and never worked well. Between 1939 and 1947 (the year FIFRA was passed) only one tolerance was established (for fluoride-based pesticides on apples and pears) and was challenged in court. However, in the 1920’s, concern about lead arsenate residues on apples led to the establishment of a “tolerance” for export to markets in Great Britain.

1. Although the numbers of pesticides began exploding during WWII, too little was known about them to even set tolerances for safe levels.

C. The growing number of new pesticides, which were very effective but whose risks were unknown presented a dilemma. In this atmosphere, Congress began work on FIFRA, which was passed in 1947 with great support from the manufacturers and users (Figure 8). 1. FIFRA repealed the Insecticide Act.



2. Rodenticides and herbicides were also covered (as well as insecticides and fungicides).

3. Pesticides had to be registered with the Secretary of Agriculture. 4. Each pesticide sold must include specific label or package information.

a. This is the heart of the law, requiring name and address of manufacturer, an ingredient statement, and directions for use which were “adequate for protection of the public”

b. Assumption that an adequate label would allow safe use 5. Did not impose testing requirements, neither for efficacy or safety; however, the

Secretary could request a full description of all tests if he felt they were needed; a. Secretary could register a product “under protest” b. Secretary could cancel a product if he felt it was necessary to protect the public

6. The main effect of the law was to allow USDA to track pesticides, i.e., keep an adequate inventory.

7. Governed pesticide regulation until 1972, when the law was significantly overhauled.

Historically Parallel Regulations

Pure Food & Drug Act(1906)

Insecticide Act(1910)

Federal Food, Drug &Cosmetic Act (FFDCA,1938) Federal Insecticide,

Fungicide & RodenticideAct (FIFRA,1947)

registration

labelling

residue tolerances

Figure 8. The parallel nature of pesticide laws and their main objectives.

D. Note that health concerns were left under the jurisdiction of the FFDCA (thus FDA rather than USDA); following FIFRA, the FDA began to develop tolerances for pesticides on food crops (Figure 8). 1. Evidence for establishing tolerances were taken at public hearings. 2. Unworkable system; (the first tolerances were not actually established until 1955); 3. New law was being drafted to improve process; first draft required manufacturers to

prove safety, which brought great protest; 4. Law finally amended in 1954 (Miller Amendment)--essentially required health and

safety data to be analyzed before a pesticide could be used on a food crop; such data would be used to develop the tolerance (Figure 9). a. The intent of the law was to withhold registration until the tolerance was

established--thus, although the Miller Amendment did not modify FIFRA, its effect was to tie together two laws for regulation of pesticides. 1. A manufacturer who had registered or sought to register a pesticide under

FIFRA for use on food crops was required to obtain a certificate of usefulness from the Secretary of Agriculture and then to petition the Secretary of Health ,



Education, and Welfare to establish a tolerance for pesticide residue, or to exempt the substance from compliance.

2. Petition had to contain: a. Name and chemical composition of pesticide; b. Application procedures; c. Data from investigations on safety; d. Results of residue testing; e. Methods for removing excess residue; f. A proposed tolerance and other grounds in support of the tolerance.

3. Any food sold containing residue in excess of tolerance was deemed adulterated.

b. Both FIFRA and Miller Amendments passed with consensus of manufacturers, agricultural interests, and the public.

5. In 1958, FFDCA was amended again by the Food Additive Act containing a provision known as the Delaney Amendment (Figure 9). The law’s intent was to regulate food additives purposefully added to foods (i.e., processed foods). Pesticides were exempted as long as they did not concentrate during processing (i.e., to levels above the tolerance for the raw agricultural commodity, which was established under the provisions of the Miller Amendment). If the pesticide residues did concentrate, a processed food tolerance would be required under the provisions of the Food Additive Act. a. However, the Delaney Amendment in the Food Additive Act stated that an

additive cannot cause cancer in laboratory animal testing, in which case it would not be permitted. If a pesticide was deemed oncogenic, then it also could be regulated under the Delaney clause. In other words, as the law was written, an “oncogenic” pesticide could not have a processed food tolerance, if one was needed as a result of residues concentrating to levels above the raw food tolerance.

b. So a paradox was created (called by the National Academy of Sciences the Delaney Paradox); an oncogenic pesticide could obtain a raw agricultural commodity tolerance and be used widely, but the residues could not legally be present in processed food. 1. To get around this paradox, the EPA had chosen to use “de minimis” risk,

which is a negligible risk defined as no more than 1 in a million excess cancers in the population.



Historically Parallel Regulations

Pure Food & Drug Act(1906)

Insecticide Act(1910)

Federal Food, Drug &Cosmetic Act (FFDCA,1938)

Federal Insecticide,Fungicide & RodenticideAct (FIFRA,1947)

Miller Amendment(1954)

Food Additives Amendment(Delaney Clause) 1958

Figure 9. Important amendments that overhauled the FFDCA.

6. The Delaney Amendment was rescinded recently with the passage of the Food Quality Protection Act during August, 1996 (discussed below)

E. After passage of FIFRA, many state legislatures enacted their own pesticide laws; mostly regulated use rather than manufacture and sale.

F. The regulation of pesticides tool place by the overlapping of responsibilities of two federal agencies. Opinion in the early 1960’s held that the laws were ineffectively administered; President Kennedy had appointed a commission to study the need for revisions to the laws prior to public interest stirred by Silent Spring. Concern over environmental effects also began to be voiced prior to publication of the latter book.

G. By 1969, Congress commissioned a study of the effect of pesticides on the environment; the study group was known as the Mrak Commission. 1. One of the first results from the study was the removal of pesticide regulation

responsibility from the USDA to the new EPA (created in 1970 under the Nixon administration).

H. DDT had really been the center of the storm of controversy over pesticide use during the 1960’s; this controversy probably spawned the major overhaul of FIFRA known as the Federal Environmental Pesticide Control Act of 1972 (FEPCA). 1. FIFRA became an environmental statute: manufacturers were required to

demonstrate that a product could be used without “unreasonable adverse effects on the environment.”



FFDCA Amended

(Food & Drug Admin.-FDA)

FIFRA

(USDA)

EPA(1970)

Federal Environmental Pesticide

Control Act (FEPCA, 1972)FDA

(food residues)

Shared Responsibilities

Figure 10. Creation of the EPA to oversee pesticide law and major overhaul of

FIFRA to address environmental concerns of pesticide use.

I. Provisions of FEPCA 1. New requirement for registration and reregistration of all products within four years

(this deadline never met; law amended again in 1978 to set new deadlines, and several times thereafter); a. An applicant for registration had to show that the pesticide would “perform its

intended function without unreasonable adverse effects on the environment...” 2. Use of any registered pesticide in a manner inconsistent with its labeling became a

crime; 3. New system of classifying pesticides--restricted vs. general use;

a. Restricted use pesticides designated as one which could cause “unreasonable adverse effects on the environment, including injury to the applicator...”, if additional regulatory restrictions were not imposed. 1. Under this system, only certified applicators could apply restricted use

pesticides 2. This provision necessitated implementation of training and certification

programs by the states; largely accomplished through universities in programs known as Pesticide Applicator Training (PAT).

b. General use pesticide could be sold to the general public (for ex., in supermarkets, nurseries, etc.) without a requirement for licensing or certification.

J. The re-registration process was observed to be a failure; by 1988, over 600 active ingredients required reregistration. In 1988, FIFRA amended again (under Reagan) requiring completion of reregistrations by 1997. Products included in the process were those registered prior to 1984. 1. Reregistration rationale

a. Historically required but never carried out by USDA; b. Pesticides registered prior to 1984 met different set of safety standards and

testing; c. Need for institution of GLPs (Good Laboratory Practices) for tracking data

validity



1. This provision of testing raises the costs significantly. It is essentially a sophisticated book keeping system requiring documentation of literally every facet of a lab and field testing operation

2. The need for GLPs grew out of a testing scandal in the late 1970’s when Industrial Biotest, a Chicago testing company that conducted many of the animal toxicity tests for manufacturers’ products, was found to have committed very serious fraud in reporting of test results, as well as mistreatment of lab animals and assorted “bad” practices.

2. Components of re-registration a. Updating of the database--EPA was to prioritize information needs.

Consideration was given to pesticide use on food or feed crops, whether use could result in contamination of groundwater, fish or shellfish; whether there were missing data; or whether farm worker exposure was likely. 1. Thus, EPA had to determine the current data requirements and ensure data

were available b. The data available had to be re-evaluated against current safety and testing criteria

and then EPA had to make determination of need for registration changes. c. After the evaluation process, EPA could require a modification in label or

cancellation of product. 1. Note that when a pesticide is granted a tolerance and prior to registration, a

label is drafted to accompany the product. 2. The pesticide label has information about the active ingredient, legal uses

(crops, sometimes specific pests), rates of application, personal protective equipment (worker protection), restrictions on use (no drift, no application near water) and proper disposal.

3. Violation of provisions on the label is a crime. d. Companies had to submit new data as required by EPA; they had 4 years with an

extension possible to conduct new studies if needed. K. Note that other environmental laws like the Clean Water Act and the Safe Drinking

Water Act affect pesticides, but these have a different legislative history and could be invoked when pesticide residues in water exceed certain standards or if an industry manufacturing or using pesticides needed to discharge wastewater.

X. The Food Quality Protection Act of 1996 (FQPA) (access the law at

http://www.epa.gov/oppfead1/fqpa/) A. In 1993, the National Academy of Sciences released a report commissioned by Congress

in the late 1980’s. The report, Pesticides in the Diet of Infants and Children, became the blueprint for amendments to FIFRA and the FFDCA. 1. The NAS report concluded that infants and children were not as well protected as

adults by the current pesticide regulations; 2. Thus, the Academy recommended changes in exposure analysis and more focus on

the types of foods eaten by kids. It also recommended that other exposures besides food be aggregated.

B. The FQPA was supported by both industry and environmental advocacy groups because its provisions were designed to eliminate balancing of risks and benefits and make pesticide regulation entirely risk based, as were other laws regulating environmental



contaminants. Furthermore, protection of children and infants would take center stage. In return, industry wanted the repeal of the Delaney amendment. 1. With elimination the Delaney amendment, all food tolerances would be unified. In

other words, no distinction would be made between raw and processed commodities. 2. Also, residues of putative carcinogenic pesticides would be permitted as long as they

met the standard of negligible risk. As a matter of fact, the negligible risk standard applied regardless of the perceived health and environmental effects.

C. Although the FQPA really amends both FFDCA and FIFRA simultaneously, the most important provisions from our perspective is how risk will be determined. How risk is determined is directed by new definitions in the law. (See Figure 11 for summary graphic of the interaction of the FQPA with FIFRA and FFDCA). 1. Before the FQPA, the law dictated that tolerances would be set to “protect public

health”. The FQPA says that tolerances will be “safe,” i.e., “a reasonable certainty that no harm will result from aggregate exposure.” Thus all pathways of exposure, food, water, residential home, garden, and lawn use would be aggregated together. a. Aggregate exposure includes exposure of a specific pesticide to all media: air,

water, soil, as well as food; 2. A “safe” tolerance considers the following factors in addition to aggregate

exposure a. Exposure of infants & children and whether they are more susceptible to the

effects of a pesticide b. Threshold vs. non-threshold effects (i.e., is the pesticide a carcinogen;

carcinogens according to EPA logic have no thresholds) c. The potential for disruption of the endocrine system; d. Cumulative exposure;

1. Requires that food containing residues of multiple pesticides with the same mechanism of toxicity be added together in considering the amount of exposure.

D. When we discuss dietary exposure of pesticide residues, we will discuss how EPA ensures safety for pesticide residue exposures.

FIFRA(1947)

FFDCA(1938)

Tolerance (“MRL”)

FEPCA(1972)

Labelling Registration

Risk Assessment

FQPA(1996)

Miller (1954)Delaney (1958)

Figure 11. Relationship of FQPA to FIFRA and FFDCA. FQPA has a profound effect on risk

assessment policy that in turn affects tolerance setting and labeling.



1. Briefly, safety is determined from the various mammalian toxicology tests for acute and chronic toxicity (see testing requirements below).

2. In these tests, the most sensitive toxicological endpoint (i.e., the adverse biochemical or physiological effect occurring at the lowest tested dose) is chosen. For this endpoint the dose causing no effect (No Observable Adverse Effect Level, NOAEL) is determined.

3. The NOAEL is divided by an uncertainty factor (100 if no extraordinary child sensitivity noted, or 1000 if child sensitivity noted) to obtain a reference dose (RfD, given in units of mg/kg/day). Any exposure s due to residues from food, water, or residential use must not exceed the RfD).

E. Consequences of the FQPA 1. The FQPA mandated that all pesticide tolerances be reassessed under the new

requirements for children’s sensitivity, endocrine disruption, aggregate exposure, and cumulative exposure. a. In 1996, there were about 10,000 pesticide tolerances ; EPA was given until 2006

to complete the assessments. b. After EPA completes a draft re-assessment (i.e., risk assessment to determine

whether exposure exceeds the RfD), then the agency issues a Re-registration Eligibility Decision document (RED). 1. REDs are available on the WEB at

(http://www.epa.gov/pesticides/reregistration/status.htm) 2. EPA chose to examine organophosphate (OP) insecticides first, and then to tackle

sol-called carcinogenic pesticides. 3. OPs were surmised to have the greatest potential for exhibiting differential effects on

children (i.e., children more sensitive at a given dosage (mg/kg body weight) than adults).

4. As a result of the reassessments, uses have been cancelled or restricted. For example, a. Chlorpyrifos in the urban use formulation of Dursban will be completely off the

market by ~2003. b. Diazinon will no longer have urban uses. c. Methyl parathion uses was cancelled for orchard fruits.

F. Secrets of the FQPA 1. The FQPA was written as a consumer protection law with no attention to worker

exposure and risk nor ecological effects and risk. 2. However, during the re-registration process (i.e., the process of reassessing the safety

of the tolerance and development of the RED), EPA does examine worker exposure and ecological effects.

3. Thus, EPA during the reassessment process can require changes in pesticide use characteristics to protect worker and ecological health.

4. Indeed, late during 2000, EPA was sued by a coalition of advocacy groups headed by National Resources Defense Council (NRDC) for failure to fully implement the FQPA, especially the provisions for cumulative exposure and risk assessment. a. In the court sanctioned consent decree, the EPA is directed to specifically tend to

worker exposure and ecological effects issues in addition to the statutory requirements of the FQPA.



XI. A New Twist Affecting Pesticide Regulation—The Coming of Age of the Lawsuit A. Over the last 25 years, EPA has been a frequent target of lawsuits over a perception that it

has failed to live up to the statutes imposed by Congress. B. Indeed, one the major impetus behind the FQPA and industry’s support of it grew out of

a lawsuit that would have likely forced EPA to suspend registration of any earmarked “carcinogenic” pesticides on raw agricultural commodities if these compounds were also subject to tolerance suspension by virtue of Section 409 of the FFDCA regarding the Delaney Amendment prohibition against carcinogenic pesticide residues in processed food.

C. Two sets of lawsuits have impacted pesticide use 1. The Federal Court for District 9 (based in San Francisco) ruled that aquatic

applications of pesticides were subject to jurisdiction as point source contaminants under the Clean Water Act. a. Thus, aquatic pesticide applications, for example, for irrigation canal weed

control, need to obtain a National Pollution Discharge Elimination System Permit. 2. A lawsuit in 2001 by the WA Toxics Coalition accused EPA of violating the

Endangered Species Act by not consulting with the National Marine Fisheries Service with regard to listed threatened and endangered runs of salmon in the Pacific Northwest (see Felsot, A. S. 2003. Salmon-stimulated lawsuits: Swimming in circles or shouldered on sound science? Agrichemical & Environmental News (February), issue no. 202. 14 pp. http://aenews.wsu.edu). a. Although EPA lost the lawsuit in Western WA District Federal Court, the agency

is now defending itself against a motion for injunction to force it to mandate specific, fixed no-spray buffer zones around aquatic habitats.

XII. Tests Required Under Current Law (Code of Federal Regulations 40, Part 158) A. Details about the specific testing requirements can be downloaded from the EPA web

site. 1. Human Health: “OPPTS Test Guidelines Series 870, Health Effects”

http://www.epa.gov/docs/OPPTS_Harmonized/870_Health_Effects_Test_Guidelines/Series/

2. Ecological Fate & Effects: OPPTS Test Guidelines Series 850, Ecological Effects, http://www.epa.gov/opptsfrs/OPPTS_Harmonized/850_Ecological_Effects_Test_Guidelines/Drafts/

B. Number & Kind of Studies Required for Registration (classification according to Leng, M. L. 1991. Consequences of reregistration on existing pesticides. pp. 27-44 in “Regulation of Agrochemicals: A Driving Force in their Evolution, G. J. Marco, R. M. Hollingworth, and J. R. Plimmer, eds., Am. Chem. Soc., Washington, D.C. ); 1. Product chemistry (26) 2. Mammalian toxicology (27) 3. Wildlife toxicity (27) 4. Toxicity to nontarget organisms (15) 5. Environmental fate (24) 6. Drift (2) 7. Residue in crops & analytical method (18)



C. Specific provisions of the 1988 amendments to FIFRA requiring data for registration--i.e., data requirements as listed in the Code of Federal Regulations: 1. product chemistry

a. Active ingredient b. Impurities

1. Some impurities may be toxicologically important; for ex. isomalathion (an isomer contaminant) is about 5 times more toxic than malathion a. malathion LD50 = > 2500 mg/kg b. isomalathion LD50 = < 500 mg/kg

P S CH C OC2H5

OS

CH3O

CH3O

CH C OC2H5

O

CH C OC2H5

O

P S CH C OC2H5

O

CH3O

OCH3S

malathion isomalathion

c. Analytical method for active ingredient d. Certifiable concentrations e. Physical & chemical characteristics

1. Useful for defining necessity for other studies a. high partition coefficient could indicate bioconcentration potential; b. vapor pressure is a consideration in setting worker reentry intervals; c. viscosity & miscibility is important to setting acceptable labeling for tank

mix and spray applications f. Production process g. Formulation process h. Dupont has been fined by EPA for a Benlate fungicide formulation contaminated

with the herbicide atrazine, even though it is not clear that the contamination actually caused crop damage or the contaminant even existed in the stocks that were used (Pesticide & Toxic Chemical News, Oct. 5, 1994).

2. Residue chemistry a. Used to estimate exposure of general population to pesticide residues in food b. Used to set and enforce tolerances c. Information required:

1. Chemical identification and composition of product 2. Amounts, frequency, and timing of application 3. Amount of residues remaining on food 4. Analytical method adequate for enforcement

a. Note that the analytical method developed for analyzing active ingredient content in a formulated product may be very different (i.e., simpler) than the analytical method needed to analyze for environmental residues

5. Practical method for removing excess residues 3. 3. Environmental fate

a. a. Generic studies required



1. Degradation 2. Metabolism 3. Mobility 4. Dissipation 5. Accumulation

b. Rationale: 1. Used to assess toxicity to humans through exposure to residues remaining

after application either in treated areas or from consuming contaminated food; 2. Used to assess the presence of widely distributed and persistent pesticides in

the environment which may result in loss of usable land, water, or wildlife resources

3. Used to assess potential exposure of nontarget organisms like fish and wildlife;

4. Used to estimate expected environmental concentrations in specific habitats where threatened or endangered species are found

c. Practical significance 1. Availability of residues to rotational crops 2. Irrigation water might contain residues 3. Setting of realistic field reentry intervals 4. Protection of potable water supplies 5. Workers may be exposed to degradation products

4. Hazards to humans & domestic animals a. Acute toxicity

1. Defines hazard of handling product; can answer questions of how hazardous dermal exposure is in relation to oral or inhalation exposure;

2. LD50 measurements by various routes of exposure b. Subchronic toxicity

1. Helps define doses to be used for chronic toxicity 2. looks at range of effects that might occur from doses that are not acutely toxic

but occur repeatedly over a limited time frame 3. Usually a 90-day study

c. Mutagenicity 1. Assess potential to affect the cell’s genetic material using a battery of different

tests 2. Compounds that damage DNA directly represent true hazards of

carcinogenicity; likely to be dropped from further development 3. Findings of mutagenic potential can be used to assess heritable effects,

oncogenicity, or other health effects; d. Chronic toxicity

1. Life-time feeding studies using maximum tolerated dose 2. Endpoint is usually carcinogenicity (actually tumorigenicity) although other

effects are measured e. Teratogenicity (birth defects) f. Reproductive effects (effects on fertility)



1. These are multigenerational studies; the pregnant rat is fed the pesticide mixed into the diet; effects on offspring are measured; ability of offspring to successfully mate and reproduce are also examined

g. Metabolism 1. Aids extrapolation of data from animals to humans; 2. Development of poisoning antidotes

h. Note that under mammalian toxicology we would now include endocrine disruptor screening studies

5. Field reentry protection studies a. Monitoring data under actual exposure conditions b. Combined with data from studies of toxicity and residue dissipation c. Practical significance: occupational exposure is the highest risk for health

hazards 6. Pesticide spray drift evaluation

a. Measure droplet size spectrum using formulations b. Drift evaluation under field conditions c. Practical significance: precautionary labeling to protect nontarget crops

7. Hazards to nontarget organisms a. Determination of pesticidal effects on birds, mammals, fish, terrestrial and aquatic

invertebrates, and plants; b. Tests include short-term acute, subacute, reproduction, simulated field, and full

field studies; c. Testing is hierarchical or tiered--if tests lower in the tier indicates a problem, then

the next test in the tier will be performed (progression is from basic lab tests on one end to applied field tests on the other end);

d. Toxicity information is compared with measured or estimated pesticide residues in the environment to assess potential impacts and decide whether further studies are warranted;

e. Long-term field studies, which include reproductive, life cycle, and plant field studies may be required if predictions of possible adverse effects in less extensive studies (i.e., lower in the tier) cannot be made, or when the potential for adverse effects is high.

8. Product performance a. Ensures that pesticide products will control the pests listed on the label; b. Unnecessary pesticide exposure to the environment will not occur as a result of

the use of ineffective products; c. Includes specific performance standards to validate the efficacy of pesticides used

in the public health area (e.g., disinfectants, rodenticides) XIII. Costs of Pesticide Development and Registration

A. R&D costs have been estimated to be over $70 million. B. Reregistration Fee estimated at $150, 000 per product (i.e., not active ingredient but

formulated product); does not include cost of any new studies that may be required C. Product maintenance fee estimated at $35,000 D. Economics of pesticide development and marketing (Leng 1991)



1. It may take 15 years from discovery for a pesticide product to attain a positive cash flow; by year 20 after discovery, the patent would have expired (the patent is usually obtained around 3 years after discovery of a new product

entom 558 pesticide topics fall 2005 october 31, 2005 lecturer: … · 2007-05-10 · regulatory...

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