crease in inflation as food prices increased. However, those estimates failed to take into account the possibility that other pest-control strategies could be used or that new technologies could be developed in the absence of chemical control (Jaenicke 1997).

A survey conducted by the Weed Science Society of America (Bridges and Anderson, 1992) estimated that the total US crop loss due to weeds is about $4 billion a year. In the absence of herbicides and best management practices, this loss could theoretically increase to $19.5 billion. The estimated loss in crops grown without herbicides ranged from 20% for corn and wheat up to 80% in peanuts (Bridges and Anderson, 1992).

Pesticide use also provides some benefits directly to consumers. Zilberman et al. (1991) estimated that every $1 increase in pesticide expenditure raises gross agricultural output by $3.00–6.50. Most of that benefit is passed on to consumers in the form of lower prices for food. Major losses prevented by pesticide use are those experienced during transport and storage. Oerke et al. (1994) estimated that about 50% of the harvested crop, particularly of such perishable crops as fruits and vegetables, could be lost in transport and storage because of insects and disease in the absence of pesticide use. Moreover, pesticide use can improve food quality in storage by reducing the incidence of such fungal contaminants as aflatoxins, known liver carcinogens, which are responsive to fungicides.

The use of herbicides has reduced the need for growers to cultivate to control weeds and that reduction has led to an increase in the practices associated with conservation tillage. These include no-till, ridge-till, striptill, and mulch-till—practices that leave at least 30% cover after planting. Leaving cover after planting reduces soil loss due to wind and water erosion up to 90%, and it increases crop residue (organic matter) on the soil surfaces up to 40% (CTIC, 1998a). Conservation tillage in the United States has increased from 26.1% of the total acreage in 1990 to 37.2% of the total acreage in 1998 (1998b). Without herbicides, widespread adoption of conservation tillage would likely not have taken place.

Although agriculture accounts for two-thirds of all expenditures on pesticides and three-fourths of total volume used, nonagricultural uses of pesticides are also substantial. Pesticides are used on some 2 million US farms but they are also used in some 74 million households (albeit at much lower rates). Expenditures for home and garden use of pesticides in US households were approaching $2 billion a year in 1996, most of it on insecticides ($1.34 billion), fungicides and repellents ($185 million), and herbicides ($479 million) (Aspelin and Grube, 1999).

Estimating the economic benefit of household pesticides is difficult in that in most cases no tangible product is sold for a profit. Benefits are often aesthetic rather than economic (although aesthetic improvement can increase traffic at a place of business or increase the resale value of a



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