Agricultural Resources: Pesticides

Pesticides – herbicide and pesticide prices and consumption



Herbicide and insecticide prices have generally risen over the past 3 years (table 25). Pesticide manufacturers increased expenditures for research and development of new products and to develop additional data to reregister older products. In addition, many pesticide manufacturers have embarked on expensive biotechnology research. Dealer costs also have risen, especially for liability insurance. Average farm-level herbicide prices rose 8.6 percent between 1990 and 1991, after a 4.7 percent hike a year earlier. Trifluralin, a major soybean and cotton herbicide, showed the greatest increase — 11.9 percent. Atrazine, a major corn and grain sorghum herbicide, was second at 10.9 percent. Farm-level insecticide prices jumped 13.0 percent, compared with 2.2 percent last year. The price of methyl parathion (used extensively in cotton production for boll weevil control) was up a whopping 41 percent in 1991, following a decrease of 24 percent a year earlier. The mild winter of 1990-91 indicated an upsurge in boll weevil pressure. Growers therefore stocked up on methyl parathion; tightening supplies and increasing the price.


Total 1991 farm pesticide use on major field crops is projected at 478 million pounds active ingredients (a.i.), up 15 million from 1990 (table 26). June planted acreage for the 10 major field crops declined from 256 million in 1990 to 253 million in 1991. The area planted to row crops, which tend to be pesticide intensive, increased, while that for small grains decreased. Corn and soybeans accounted for 82 percent of herbicide consumption, corn and cotton 73 percent of insecticide consumption, and peanuts 82 percent of fungicide consumption in 1990.

Pesticide Use on Fall Potatoes

Fall potatoes are grown across the northern United States, from Maine to Washington. Herbicides were applied to 81 percent of the fall potato acreage in the 11 surveyed States (table 27). However, in Minnesota and North Dakota, where rainfall is low, only 40 to 50 percent of the acreage is treated with herbicides. Insecticide use was fairly uniform across all States (table 28). The proportion of acreage treated with fungicides was highest in the humid eastern States and lowest in the more arid western States (table 29). Herbicides were applied once on 59 percent of the fall potato acreage, and twice on 20 percent. Insecticide treatments averaged 2.1, ranging from 1.2-1.3 in Colorado and Idaho to 4.5 in Pennsylvania. Fungicide treatments were highest in Maine at 8.9, followed by Pennsylvania and Wisconsin at 4.9. In the Pacific Northwest, average fungicide treatments ranged from 1.4 to 1.7.


Metribuzin was the most commonly used herbicide in fall potato production (table 27). It was either used alone or in combination with other herbicides to broaden the weed control spectrum. Metribuzin requires moisture, shortly after treatment, to be effective. A large share of the fall potatoes in the Pacific Northwest are treated with metribuzin because most of the crop is irrigated. Metribuzin, generally applied after planting but before potatoes emerge, controls such weeds as foxtail, ragweed, pigweed, and mustard. EPTC was the second most commonly used herbicide. It is a selective herbicide that can be applied preplant or after planting prior to weed germination. It controls pigweed, foxtail, and wild oats. EPTC must be incorporated into the soil because it is readily lost by volatization. It is most effective where rainfall is low, and is more often used in arid areas.


Colorado potato beetles, aphids, and leafhoppers constitute the major insect problems in potato production. The Colorado potato beetle has developed some resistance to a number of organophosphorus insecticides, and to some of the newer synthetic pyrethroids. The most commonly used insecticides across all States are esfenvalerate, methamidophos, and phorate (table 28). Carbofuran and phosphamidon are used extensively in Minnesota and North Dakota. Carbofuran, a systemic, is generally applied at planting for flea beetle and early-season Colorado potato beetle control. Phosphamidon, an organophosphate, is still effective against the Colorado potato beetle and is inexpensive to use.


Mancozeb, maneb, and chlorothalonil are the most commonly used fungicides in fall potato production (table 29). Early and late blight are the two most serious diseases. Early blight kills the potato vine, reducing the food supply available for tuber production in the hill. Late blight kills the vine, and can also infect developed tubers, making them vulnerable to decay in storage. The disease organism is harbored in volunteer potato plants and in decaying vines and tubers left in the field. The disease organism contaminates the potato plant when rain splashes infected soil particles onto the foliage. Mancozeb, maneb, and chlorothalonil are protective fungicides in that they must kill the disease organism before it invades the foliage. This explains the large number of fungicide treatments in high rainfall areas.

Herbicides on Winter Wheat

In 1991, herbicides were used on 27 percent of the winter wheat acreage in the surveyed States in 1991 (table 30). In Washington 92 percent of winter wheat acreage was treated, followed by Oregon and Montana at 76 and 73 percent. In the Corn Belt, the proportion treated ranged from 4 to 10 percent. In Washington and Oregon, winter annual broadleaf and grass weeds must be controlled during mild portions of the winter. In Montana, winterkill thins wheat stand and invading weeds must be controlled to prevent additional yield losses. Chlorsulfuron and 2,4-D were the two most commonly used herbicides. Chlorsulfuron, registered in 1982, controls broadleaf and grass weeds and can be applied either pre- or postemergence. In contrast, 2,4-D controls only broadleaf weeds and is applied postemergence. Chlorsulfuron gained rapidly in popularity and by 1988 accounted for 49 percent of the winter wheat herbicide acre-treatments but by 1991 dropped to 23 percent. The reason is that weeds resistant to chlorsulfuron have been identified (kochia and Russian thistle) and farmers have been urged to rotate chlorsulfuron with other herbicides to slow resistance in other weed species.

Regulatory Issues

In October 1990, the Environmental Protection Agency (EPA) proposed cancelling all granular formulations of carbofuran (a soil insecticide and nematicide), because of their association with bird mortality. EPA and the manufacturer have recently reached an agreement to severely restrict the sales of granular carbofuran and phase out many registered uses. Sales of granular carbofuran from September 1, 1991, through 1994 are limited to 4.5 million pounds a.i. with no more than 400,000 pounds a.i. sold in 1994. For the 1993 growing season, all registered uses will be canceled except corn, sorghum (in Texas, Kansas, and Nebraska), rice, spinach grown for seed, cucurbits, cranberries, bananas, and pine progeny. Corn and sorghum uses will be dropped after September 1, 1993. Rice use will be dropped after September 1, 1994. The agreement allows the manufacturer to present new information to EPA concerning benefits or risks on corn, sorghum, or rice before the cancellation dates. If the new evidence is persuasive, EPA could allow continued usage on corn, sorghum, and/or rice. Beginning in 1995, no more than 2500 pounds a.i. of granular carbofuran formulations can be sold for the remaining uses: spinach grown for seed, cucurbits, cranberries, bananas grown in Hawaii, and pine progeny. EPA also recently reached an agreement with the manufacturer of ethyl parathion to voluntarily cancel all registered uses as of December 31, 1991, except for alfalfa, barley, corn, cotton, sorghum, soybeans, sunflowers, and wheat. Use on canola might be available, if a residue tolerance is set. EPA has the option to review and cancel the remaining registered uses. Under the agreement, only aerial application by certified applicators is allowed, and crops treated with ethyl parathion have to be harvested mechanically. There are also application restrictions, including requirements for setbacks, reentry, wind speed, and protective clothing. A final regulatory decision on EBDC fungicides (maneb, metiram, and mancozeb) is likely in late 1991 or early 1992. EBDC fungicides used on a wide variety of fruit, nut, vegetable, and grain crops are suspected of causing birth defects and tumors. In December 1989, EPA proposed canceling 45 of 55 registered uses. Earlier that year, four major registrants withdrew 42 of the 45 uses from their product labels. Another issue concerning pesticides is the “circle of poison.” The circle of poison refers to the potential linkage between domestic production and export of certain pesticides and the subsequent import of food products contaminated with those pesticides. Of particular concern are pesticides that are neither registered in the United States nor available to U.S. farmers but, are legally manufactured and exported by U.S. companies. These pesticides can be used on food crops in foreign countries and exported for U.S. consumption. The circle is complete when pesticide residues appear on food consumed in the U.S. The most controversial aspect of legislative proposals to sever the circle of poison is banning exports of unregistered pesticides manufactured in the United States. The Circle of Poison Prevention Act, introduced in Congress in late April, would ban the export of all pesticides which are not registered domestically or do not have food tolerances.

Table 25 — April farm pesticide prices 1/


Pesticides 1989 1990 1991 90-91

Dollars per pound 2/ Percent


Alachlor 5.40 5.70 6.15 7.9

Atrazine 2.70 2.93 3.25 10.9

Butylate 3.10 3.13 3.34 6.7

Cyanazine 5.003 5.43 5.65 4.1

Metolachlor 6.61 6.94 7.49 7.9

Trifluralin 6.60 6.70 7.50 11.9

2,4-D 2.61 2.71 2.83 4.4

Composite 3/ 4.43 4.64 5.04 8.6


Carbaryl 4.08 4.36 4.44 1.8

Carbofuran 9.51 9.77 10.39 6.3

Chlorpyrifos 9.05 9.65 10.65 10.4

Fonofos 8.96 9.52 6/ 10.30 8.2

Methyl parathion 4/ 3.85 2.94 4.15 41.2

Phorate 6.85 7.25 7.78 7.3

Pyrethroids 5/ 48.08 6/ 50.00 56.54 13.1

Terbufos 10.13 10.52 11.28 7.2

Composite 3/ 10.67 10.91 12.33 13.0

(1)Derived from the April survey of farm supply dealers conducted by NASS, USDA. (2)Active ingredients. (3)Includes above materials and other major materials but not products registered in the last 2 to 3 years. (4)Supplied by Fred Cooke, Mississippi Agricultural Experiment Station. (5)Average of fenvalerate and permethrin prices based on 2.6 pounds active ingredients per gallon. (6)Revised.

Table 26 — Projected pesticide use on major U.S. field crops, 1991

June 1

planted Herbi – Insecti – Fungi –

acres cides cides cides

Million Million pounds (a.i.)


Corn 74.29 226 27.9 0.06

Cotton 13.9 21 20.5 0.22

Grain sorghum 11.0 11 1.7 0.00

Peanuts 2.0 7 1.6 7.25

Soybeans 59.8 106 9.2 0.06

Tobacco 0.8 1 2.9 0.38

Total 162.4 372 63.8 7.97

Small grains:

Barley and oats 17.6 4 0.1 0.00

Rice 2.9 12 0.5 0.07

Wheat 70.0 15 2.0 0.81

Total 90.5 31 2.6 0.88

1991 total 252.9 403 66.4 8.85

1990 total 256.0 392 62.9 8.34

COPYRIGHT 1991 U.S. Department of Agriculture

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