Aerial eradication of Columbia's coca fields has cut the current crop size by 32 percent since January, according to a report released by the United Nations. The United States sponsors the spraying.

Coca is the main ingredient used in producing cocaine. Vast fields of the crop are grown in Peru, Bolivia and Columbia in the Andes Mountains. The U.N. report said the Drug Control program has reduced Columbia's crop from 251,940 acres in December to 170,430 acres by the end of July.

"The reduction is heavy, and it seems as if it's accelerating," Klaus Nyholm, chief of the U.N. anti-drug efforts in Colombia, said in the report.

Some environmental groups have criticized the crop spraying program, because they are concerned about the long-term affect on the environment and human health.

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