Agriculture Reference
In-Depth Information
Figure 1.2 Global sales ofherbicides in 1985 for the world's major crops.Data are
expressed as percentages oftotal herbicide sales.(After Jutsum,1988.)
In the USA,herbicide application to agricultural land has risen nearly four-
fold since 1966 (National Research Council,1989, p.45), and now exceeds 200
million kg of active ingredients annually (Aspelin & Grube, 1999). Herbicides
used for maize, soybean, wheat, cotton, and sorghum account for most pesti-
cides applied to American cropland (Aspelin & Grube, 1999; United States
Department of Agriculture, 1999 a ) (Table 1.1).
Herbicide use is also intensifying in many developing countries. In India,
herbicide use increased more than 350% from 1971 to 1987, primarily for
wheat and rice production (Alstrom, 1990, pp. 167-8). From 1987 to 1992,
herbicide sales in South Asia and East Asia grew about 4% per year (Pingali &
Gerpacio, 1997).By the early 1990s, herbicides were applied to half of the area
planted with rice in the Philippines (Naylor, 1994) and more than 40% of the
land planted with wheat in Punjab and Haranya, the two states that account
for a third of India's total wheat production (Gianessi & Puffer, 1993). Sales
and application of herbicides and other pesticides are also expanding in many
regions of Latin America and certain areas of Africa (Repetto & Baliga, 1996,
pp.3-8).
Multiple factors promote the use of herbicides as primary tools for weed
management. Herbicides can markedly reduce labor requirements for weed
management in both mechanized (Gunsolus & Buhler, 1999) and nonmecha-
nized (Posner & Crawford, 1991) farming systems. Consequently, herbicides
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