Agriculture: Facts and Figures
As people settled into established societies they began looking for ways to protect their crops. Sulfur was used as an insecticide long before 500 BC. Toxic formulations of lead, arsenic and mercury were applied to crops in 1400s. In the 1600s nicotine compounds were extracted from tobacco leaves and used as insecticides. By the mid 1800s, the heads of chrysanthemum flowers were used to obtain pyrethrum and rotenone was extracted from the derris plant.
While these so-called first-generation pesticides were derived from plants, the second-generation pesticides such as DDT were formulated in chemistry laboratories. A major chemical industry sprang up after the discovery of the potent insecticidal properties of DDT by entomologist Paul Mueller. The second-generation DDT soon became the planet's most popular pesticide and Mueller received the Nobel prize in 1948.
In the 1930s the crop yields in the United States were comparable to those of India, England, and Argentina. Since the 1950s the use of petroleum-derived pesticides, fertilizers and a host of governmental policies have vaulted the U.S. into the biggest farming economy in the world. Today, fewer farmers feed more people than ever before in the history of food production.
This farming success, however, has not happened without enormous costs and environmental tradeoffs. Pesticide proponents argue that the benefits far outweigh the harm. After all, pesticides do save lives. Since the late 1940s DDT has prevented millions from contracting malaria, bubonic plague and typhus. Proponents also contend that pesticides work faster and are more effective than the alternatives. Pesticide advocates also point out that the new-generation pesticides are used at very low application rates compared to the older, out-dated products.
Insects breed rapidly, however, and quickly develop resistance to insecticides. In addition, broad-spectrum pesticides kill natural predators that keep pests in check. Use of synthetic pesticides -- which include insecticides, rodentacides, fungicides, herbicides, and others -- has increased more than 33 fold in the last half century. Ironically, it is estimated that more of the U.S. food supply is lost to pests today (37%) than in the 1940s (31%). i Total crop losses from insect damage alone have nearly doubled from 7% percent to 13% during that period. Cultivation of four crops -- soybeans, wheat, cotton and corn -- consumes around 75% of the pesticides in the U.S.
In addition, for more than 40 years, ranchers and growers have been feeding low levels of penicillin, tetracycline, and other antibiotics to poultry, cattle, and pigs to speed growth and cut costs. That use accounts for about one third to one half of all antibiotics sold in the U.S. Scientists worldwide have decried the use of antibiotics to promote animal growth because it increases the prevalence of bacteria that are resistant to antibiotics' effects and jeopardizes human health. Today about 2.5 million tons of pesticides are used worldwide.
Every day the environmental and health consequences of commercial farming become more apparent. The EPA has identified agriculture as the greatest nonpoint source of water pollution. ii Pesticides and nitrates from fertilizers and manure have been detected in the groundwater of most states. In fact pollutants from agriculture can be detected in both the north and south poles and in the deepest reaches of the oceans. Commercially-grown food we eat contains detectable levels of pesticides and antibiotics. And recent studies have implicated pesticides as the possible culprits in causing Parkinson's Disease, as well as increased aggression in children. iii
For reasons such as these and others, sustainable alternatives to intensive, high-chemical input agriculture are gaining in popularity.
Dr. Hatherill is a research toxicologist at the Environmental Studies Program at University of California at Santa Barbara. He is the Chief Scientific Advisor to EarthSave International and the author of "Eat to Beat Cancer."
i Pimental, David, et al. 1992. Environmental and
Economic Cost of Pesticide Use, BioScience, Vol. 42,No.10, 750-60