Pesticides

William M. Simpson, Jr.

Key words: norbicides, herbicides, insecticides, fungicides, rodenticides, adjuvants

World pesticide use exceeded 5.6 billion pounds of active ingredient (AI) in 1999, the latest year for which figures are available. Herbicides (chemicals used to control plants, usually weeds) accounted for the largest proportion (38%). Insecticides and fungicides were 25% and 10% of the total used, respectively (1).

The United States used 1.2 billion pounds of AI or more than 20% of the world's pesticide consumption. Herbicides were the largest category of use (46%), but insecticides were only 9% and fungicides 7% of the total pesticide market. While fungicide use in the United States and world markets is similar, insecticides are much more heavily used globally primarily due to the need for more widespread mosquito control (1).

Other pesticides account for 27% and 38% of the world and United States pesticide use, respectively. Categories included in other pesticides category are nematicides, fumigants, rodenticides, molluscicides, aquatic and fish/bird pesticides, plus other chemicals used as pesticides (e.g., sulfur and oils) (1).

Specialty biocides (used for recreational and industrial water treatment and as disinfectants and sanitizers), chlorine and hypochlorites (used as disinfectants for potable, waste, and recreational water), and wood preservatives are also considered pesticides. If the amount of AI used for these purposes is included in pesticide use data, total AI used in the world and the United States is four times higher (e.g., 5 billion pounds of AI in the United States).

Gross AI figures do not accurately reflect what has happened in world and U.S. agriculture over the past 20 years. Total pesticide use has dropped by about 20% over that time period—herbicides by 10% and insecticides by 50% (this does not reflect the likely increase in use of insecticides for West Nile virus prevention that has occurred in the last 5 years), and fungicides by 30%. In addition, the specific types of AI have also changed. The trend, generally, has been to decrease use of more toxic pesticides of all types and replace them with lower risk products (lower risk to humans, birds, fish, and beneficial insects) (1).

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