PESTICIDES IN AGRICULTURE AND THE ENVIRONMENT - CHAPTER 3 ppsx

Synthetic organic pesticide use grew rapidly from the late 1940s to the early1980s as the percentage of crop acreage treated with pesticides increased.. in 1964 to 572 million * Estimate

Economic Issues of Agricultural Pesticide Use and Policy in the United States

Craig D Osteen and Merritt Padgitt*

Economic Research Service

U.S Department of Agriculture

Washington, D.C., U.S.A

The development and growing use of synthetic organic pesticides have been anintegral part of a technological revolution in U.S agriculture that increased pro-ductivity by 2.5-fold between 1948 and 1994 [1] Synthetic organic pesticide usegrew dramatically from the late 1940s to the early 1980s before stabilizing andincreased at a much slower rate through the 1990s.† Major factors affecting thetrend since 1980 have been the development and use of new pesticides withreduced application rates and of genetically modified crops that reduce or modifythe use of conventional pesticides

Growth in pesticide use has created many controversies about potentialeffects of pesticide use on food safety, water quality, worker safety, wildlife

* The authors are agricultural economists with the Resource Economics Division, Economic Research Service, U.S Department of Agriculture The views presented are those of the authors and do not represent the official views of any agency or organization.

† The discussion of pesticide use trends is based on data collected through 1997, which were available when this chapter was written.

mortality, and pest control These controversies reflect two major themes thathave influenced the evolution of pesticide and pest management policy [2,3]:

1 Increasing pesticide use may be counterproductive for pest control,resulting in higher pest damages or control costs

2 Undesirable health or environmental effects of the use of some cides may outweigh production benefits

pesti-Increased public concern about the dietary risks of pesticides during the 1980sand 1990s led to a major change in pesticide law New public concerns aboutthe potential effects of genetically modified crops on pest control, human health,and the environment are emerging The current focus of pesticide policy is onreducing dietary and other pesticide risks to meet safety standards rather thanweighing risks and benefits and on mitigating adverse impacts by finding “safer”alternatives Integrated pest management (IPM) has become a policy tool forreducing the risks of pesticide use as well as an approach for improving theeffectiveness of pest control This chapter discusses major pesticide use trends

in the United States; the effects of such factors as pesticide productivity, farmprograms, and pesticide regulations on use; and changing law and policy

Effective chemical control of agricultural pests became prevalent in the 1800s[4] Paris green (copper acetoarsenite) was developed in the United States in the1870s to combat the potato beetle, and Bordeaux mixture (quicklime and coppersulfate) was developed in France in the 1880s to control disease in grape culture.Prior to World War II, arsenicals, sulfur compounds, and oils were commonlyused However, the development of synthetic organic materials, such as 2,4-Dand DDT, during World War II heralded the modern age of chemical pesticides.Pesticide expenses as a portion of farm production expenses (excluding operatordwellings) rose from 0.2% in 1920 to 4.8% in 1997 [5]

Synthetic organic pesticide use grew rapidly from the late 1940s to the early1980s as the percentage of crop acreage treated with pesticides increased By thelate 1970s, growth of pesticide use had slowed, because high proportions of cropacreages were being treated annually Trends in pesticide use since 1980 havebeen heavily influenced by changes in crop acreage and the replacement of oldercompounds with new ones applied at lower per-acre rates Synthetic organic pes-ticide use increased during the 1990s, but more slowly than before 1980 The U.S.Environmental Protection Agency (USEPA) published estimates that agriculturalpesticide use grew from 366 million lb of active ingredient (a.i.) in 1964 to 843

F IGURE 1 Quantity of agricultural pesticides used in the United States (Datafrom Ref 6.)

million lb in 1979, fell to 658 million lb in 1987, but rose to 770 million lb in

1997 (Fig 1) [6] (Estimates exclude sulfur, petroleum oil, wood preservatives,biocides, and other nonconventional chemicals.)

Some economists developed quality-adjusted indices that show larger term increases in pesticide use than the USEPA quantity estimates, because thematerials used and their properties, such as toxicity and persistence, have changedover time In particular, pesticides applied at rates of a fraction of a pound peracre have replaced pesticides applied at rates of several pounds per acre to controlthe same pests Ball et al [1] and Fernandez-Cornejo and Jans [7] developedquality-adjusted indices that showed that use increased by about threefold from

long-1968 to 1992, while unadjusted USEPA quantity estimates increased by 1.6 times.Padgitt and others [8,9] developed aggregate use estimates for major cropsfrom 1964 to 1997 from U.S Department of Agriculture (USDA) pesticide sur-veys.* Use on these crops grew from 215 million lb a.i in 1964 to 572 million

* Estimates in Table 1 and Figure 2 were constructed for corn, soybeans, wheat, cotton, potatoes, other vegetables, citrus fruit, apples, and other fruits and berries from USDA surveys conducted between 1964 and 1997 In years when the surveys did not include all states producing the crop, the estimates assume use rates similar to those of surveyed states These estimates account for 52–56%

of cropland acres for the 1964, 1966, and 1971 estimates and 67–70% of cropland acres for the 1982–1997 estimates These estimates exclude use on such major crops as peanuts, rice, sorghum, barley, oats, rye, other grains, tobacco, alfalfa, hay, pasture, and nuts, because they were not surveyed

or were surveyed only in a few years after 1982, making estimation of use after that date difficult The excluded crop uses contribute to the differences between these estimates and the USEPA estimates [6] These estimates also exclude sulfur, oils, and other nonconventional pesticides as well as postharvest pesticide use.

F IGURE 2 Pesticide use on major crops (Data from Refs 8 and 9.)

lb in 1982, fell to 478 million lb in 1991, and rose to a high of 588 million lb

in 1997 (Fig 2 andTable 1).Major components in that trend were:

1 An increase in pesticide use on corn and soybeans from 50 million lba.i in 1964 to 421 million lb a.i in 1982, and then a decline to 312million lb a.i in 1997

2 An increase in pesticide use on potatoes and other vegetables from 27million lb a.i in 1964 to 139 million lb in 1997

3 An increase in pesticide use on cotton from 95 million lb a.i in 1964

to 112 million lb a.i in 1971 and then a decline to 68 million lb a.i in1997—a trend heavily influenced by changes in insecticide ingredientsapplied

4 An increase in herbicide use on major crops from 48 million lb a.i in

1964 to 430 million lb a.i in 1982 and then a decline to 366 million

lb a.i in 1997

5 An increase in insecticide use from 123 million lb a.i in 1964 to 132million lb a.i in 1976, a dramatic fall to 83 million lb a.i in 1982, and

a continuing decline to 50–60 million lb in the 1990s

6 An increase in fungicide use from 22 million lb a.i in 1964 to 51million lb a.i in 1997

7 An increase in use of “other pesticides” from 21 million lb a.i in 1964

to 110 million lb a.i in 1997

8 A change in the mix of pesticides used over time, which reduced age application rates per acre, especially for herbicides and insecti-

aver-cides Also, during the 1990s, the number of pesticide treatments andingredients applied per acre increased and an increasing proportion oftreatments were made after planting rather than before or at planting.

2.2 Insecticides

In the 1950s, insecticides were widely used on a variety of high value cropsincluding cotton, tobacco, fruits, potatoes, and other vegetables(Table 2)[10–15] Somewhat later, insecticide use on other major field crops, particularly corn,increased rapidly Insecticides were applied to less than 10% of corn acreageduring the mid-1950s but to 35–40% by 1976 Since the mid-1980s, the propor-tion of corn acres treated fell from 45% to 25–30% in the 1990s The proportion

of cotton, potatoes, and many fruit and vegetable acres treated with insecticidesremained high in the 1990s (Tables 2–4)[16,17]

The quantity of insecticide applied to major crops increased from 1964 to

1976 but in 1997 declined to less than 50% of that in 1976 (Table 1) Cottonand corn accounted for most of that decline Cotton insecticide quantity fell from

73 million lb a.i in 1971 to 64 million lb in 1976 and to 19 million lb in 1982,and varied between 10 and 30 million lb from 1982 to the late 1990s Corninsecticide quantity declined from 30 million lb a.i in 1982 to less than 21 million

lb a.i in the 1990s

The decline in insecticide use reflects the changes in the compounds used,with reduced per-acre application rates In the 1960s and 1970s, organophos-phates and carbamates replaced organochlorines (Table 5) [12,18–21].* (Seefootnotes to Table 5 for examples of pesticides in the major classes.) Syntheticpyrethroids were rapidly adopted after their introduction in the late 1970s andaccounted for over 20% of insecticide acre-treatments by 1982.† However, insec-ticide groups used in the 1960s—the organochlorines, organophosphates, andcarbamates—still accounted for over 90% of insecticide quantity, and many ac-tive ingredients used in the 1960s continued to be widely used in the 1990s.The use of other new, low-rate insecticides, including abamectin (an antibiotic),diflubenzuron (a benzoylphenyl urea), and imidacloprid (a chloronicotinyl), in-creased during the 1990s Synthetic pyrethroids and newer insecticide groupsaccounted for less than 5% of insecticide quantity in 1997 but because of their lowrates of application, accounted for about one-third of insecticide acre-treatments.The adoption of genetically modified crops may influence future insecticideuse trends, but emerging concerns about their pest control, environmental, and

* The estimates for insecticide and herbicide families are restricted to use on corn, cotton, soybeans, wheat, and potatoes, which were surveyed in more years than the other major crops.

† Acre-treatments are the number of acres treated with a pesticide multiplied by the average number

of treatments per acre.

T ABLE 1 Estimated Quantity (Millions of Pounds) of Pesticide Active Ingredients Applied to Selected U.S Crops,1964–1997a

Source: Refs 8 and 9.

T ABLE 2 Share of Crop Acres (Percent) Treated with Insecticides

b See Table 3 for more detailed fruit information.

c See Table 4 for more detailed vegetable information.

Source: Refs 10–15.

T ABLE 3 Fruit-Bearing Acreage Treated with Pesticides, Major Producing States, 1993–1997

Percent of planted area receiving applications

a Surveys were conducted in major producing states; the set of minor producing states surveyed was modified slightly between years.

b Insufficient reports to estimate.

Source: Ref 16.

T ABLE 4 Vegetable Acreage Treated with Pesticides, Major Producing States, 1992–1996

Percent of planted area receiving applications

a Surveys were conducted in major producing states; the set of minor producing states surveyed was modified slightly between years.

b Insufficient reports to estimate.

Source: Ref 17.

T ABLE 5 Shares (Percent) of Insecticide Use by Class

Insecticide class 1964 1966 1971 1976 1982 1991 1997Quantity

health effects could limit further adoption Crops that include a gene that produces

the Bacillus thuringiensis (Bt) toxin to control Lepidopteran pests were

intro-duced in the mid-1990s This technology helps to control the European cornborer, a target for insecticides on a small portion of corn acreage, and bollworm,tobacco budworm, and pink bollworm, major targets for cotton insecticide use.USDA surveys showed that Bt-treated seed was planted on 19% of corn acreageand 17% of cotton acreage in the surveyed states in 1998 [22] Bt-treated seedwas planted on 35% of cotton acreage in the Mississippi Delta states, where amajor portion of insecticide treatments is for bollworms and budworms

2.3 Herbicides

Herbicide quantity increased rapidly from the late 1950s before stabilizing in the1980s Approximately 10% of corn and wheat and 5% of cotton acres were treated

with herbicides in 1952(Table 6).Herbicide use on corn, cotton, and soybeans(for which there are no data before 1966) stabilized at 90–97% of acres plantedsince 1980 Winter wheat herbicide use has varied in the range of 30–60% ofplanted acreage since 1986, while spring wheat use has varied between 80% and95% Limited data show similar increases for potatoes, peanuts, rice, and sor-ghum as well as for other fruits and vegetables(Tables 3, 4,and 6).

Herbicide quantity on the major crops increased dramatically between 1964and 1982 (by 8.9-fold), but in the 1990s was 15–20% lower than estimated for

1982 (Table 1) The quantity applied to corn and soybeans, which account forthe major portion of herbicide use, grew from 30 million lb a.i in 1964 (62%

of use on the major crops) to 377 million lb a.i in 1982 (88%), before falling

to 296 million lb (81%) in 1997 The quantity of herbicides used on cotton, wheat,vegetables, and fruit generally increased between 1964 and 1997, but these cropsaccounted for a declining share of herbicide use

Much of the decline in quantity since 1982 was due to reduced crop acreage,particularly during the 1980s because the proportion of acreage treated with herbi-cides remained high, and to lower application rates for commonly used herbicidessuch as atrazine But the change in the herbicide compounds used, which alsoreduced average application rates per acre, contributed (Table 7) [12,18–21].Shares of total herbicide quantity declined for phenoxys, phenyl ureas, and benzo-ics between 1964 and 1997 and for carbamates since 1982 (See footnotes forTable 7 for examples of herbicides in each class.) During this time, shares grewsignificantly for amides and anilines The share for triazines increased until 1976,then declined, but still exceeded 20% in the 1990s New families of herbicidesintroduced since the 1970s account for increasing shares of use and include phos-phinic acids, bipyridyls, benzothiadiazoles, benzoxazoles, oximes, pyridazinones,pyridines, sulfonyl ureas, and imidazolinones Herbicide groups reported in the1960s accounted for over 80% of herbicide applied in 1997, but families notreported before 1976 accounted for about 40% of acre-treatments In particular,the shares for phosphinic acids and sulfonyl ureas have grown dramatically since1982

The adoption of genetically modified, herbicide-tolerant crops may ence future herbicide use trends by encouraging the application of specific herbi-cides, which might otherwise kill the crop, to control weeds Emerging concernsabout environmental and health effects and the development of herbicide-resistantweed species could limit further adoption Currently, herbicide-tolerant corn, cot-ton, soybeans, and canola have been developed The most commonly planted areglyphosate-tolerant, but glufosinate ammonium–tolerant corn and bromoxynil-tolerant cotton are also available USDA surveys showed that herbicide-tolerantseed was planted on 18% of corn, 44% of soybean, and 26% of cotton acreage

influ-in surveyed states influ-in 1998 [22] These are large influ-increases from 3% of corn, 7%

of soybeans, and less than 1% of cotton acreage in 1996 The increased acreage

T ABLE 6 Share (Percent) of Crop Acres Treated with Herbicides

b See Table 3 for more detailed fruit information.

c See Table 4 for more detailed vegetable information.

Source: Refs 10–15.

T ABLE 7 Shares (Percent) of Herbicide Use by Class

Herbicide class 1964 1966 1971 1976 1982 1991 1997Quantity

d Diuron, linuron, fluometuron, terbacil.

e Alachlor, acetochlor, metolachlor, propachlor.

f Atrazine, cyanazine, propazine, simazine, metribuzin, ametryne.

g Dinoseb, DNBP.

h Butylate, EPTC, pebulate.

i Oryzalin, pendimethalin, ethalfluralin, trifluralin.

j Chloramben, dicamba, naptalam.

k Glyphosate, glufosinate-ammonium.

l Chlorsulfuron, halosulfuron, metsulfuron, nicosulfuron, primisulfuron.

m Includes bipyridyls (paraquat), benzothiadiazoles (bentazon), benoxazoles prop), imidizolinones (imazaquin, imazethapyr), diphenyl ethers (acifluorfen, diclofop, lactofen, oxyfluorfen), oximes (clethodim, clomazone, sethoxydim), pyridines (clorpyr- alid, fluazifop), pyridazinones (norfluorazon), and others that first appeared in pesticide use surveys since 1976.

(fenaxa-n Sum of acreage treated with a pesticide multiplied by average number of applications per acre.

Source: Refs 12, 18–21.

of herbicide-tolerant crops may be a factor in the dramatic increase of glyphosate(the primary phosphinic acid) use in the 1990s.

2.4 Fungicides

The estimated quantity of fungicides used on the major crops increased by about2.3 times between 1964 and 1997 (Table 1) Fruits and vegetables, includingpotatoes, accounted for over 94% of fungicide use over that time period Most

of the increase occurred on potatoes and vegetables—more than 4.5-fold between

1964 and 1997 Potato acreage treated with fungicides increased steadily from24% in 1966 to 85–98% in the 1990s(Table 8).An estimated 20% of the acres

of “other vegetables” were treated with fungicides in 1966 and 1971, and by the1990s much higher proportions of the acreage of many vegetables, such as celery,tomatoes, lettuce, melons, strawberries, and green peas, were treated(Table 4)

By the early 1970s, a high proportion of fruit acreage was treated with fungicides,including about 70% of apple acreage and over 50% of citrus acreage Duringthe 1990s, somewhat higher proportions of apple, citrus, and other fruit cropacres were treated (Table 3)

As is the case for herbicides and insecticides, the change in fungicide pounds used over time contributed to lower per-acre application rates(Table 9)[12,18–21] (See footnotes to Table 9 for more widely used fungicides in eachclass.) Shares of quantity declined for inorganics (primarily copper compounds)and dithiocarbamates since the 1960s but increased for phthalimides.* However,pthalimides, inorganic materials, and dithiocarbamates together accounted forover 90% of fungicide quantity in the 1960s and still accounted for almost 90%

com-in 1997 The shares of newer groups, such as benzimidazoles, azoles, mides, metal organics, and acyclalanines accounted for about 10% of quantitybut 35% of acre-treatments in 1997

dicarboxi-2.5 Other Pesticides

The estimated quantity of “other pesticides” used on the major crops increased

by over fivefold between 1964 and 1997 (Table 1) This category includes soilfumigants, desiccants, harvest aids, and growth regulators For the crops included,cotton, fruits, and vegetables accounted for virtually all of the quantity in thelate 1990s.† Growth in the use of fumigants on potatoes and other vegetablesand of sulfuric acid (a harvest aid) on potatoes accounts for much of the increased

* Estimates of shares of fungicide families include use on fruits and vegetables as well as corn, soybeans, cotton, wheat, and potatoes.

† Tobacco is a major use of “other pesticides” not included in these totals, but the proportional growth

in use has not been large Estimated use on tobacco was 18 million lb in 1964, 19 million lb in 1976, and 25 million lb in 1996.

T ABLE 8 Share (Percent) of Crop Acres Treated with Fungicides (Excluding Seed Treatments)

b See Table 3 for more detailed fruit information.

c See Table 4 for more detailed vegetable information.

Source: Refs 10–15.

T ABLE 9 Share (Percent) of Fungicide Use by Class

b Includes captan, chlorothalonil.

c Includes maneb, mancozeb, metiram, thiram.

d Primarily copper compounds; excludes sulfur.

e Metalaxyl.

f Includes fenbuconazole, propiconazole, myclobutanil, triadimefon, and others.

g Includes benomyl, thiophanate-methyl, and thiabendazole.

h Includes iprodione, vinclozolin.

i Includes fosetyl-aluminum and triphenlytin hydroxide.

j Total acreage treated with a pesticide multiplied by average number of applications per acre.

T ABLE 10 Share (Percent) of Crop Acres Treated with Other Pesticides

b See Table 3 for more detailed fruit information.

c See Table 4 for more detailed vegetable information.

Source: Refs 10–15.