Problems with Pesticide Use—Impact on Other Organisms

Many of the pesticides are toxic to organisms other than those especially targeted. One of the greatest concerns with the development and use of these substances is their slow breakdown and their ability to accumulate in organisms.

A major problem of pesticide use is that their widespread use accelerates the development of genetic resistance to pesticides. Because of genetic resistance, many insecticides (such as DDT) no longer protect people from insect-transmitted diseases (malaria, for example) in some parts of the world.

Another problem is that broad-spectrum insecticides kill natural predators and parasites that help control the populations of pest species.

Also, pesticides do not stay put. According to USDA, no more than 2% of the insecticide applied to crops by aerial or ground spraying reaches the target pests. Also, less than 5% of herbicides applied to crops reach the target weeds.

Pesticides that miss their target pests can end up in the air, surface water, groundwater, bottom sediments, food, and nontarget organisms, including humans and wildlife: at high enough levels, most pesticides can be toxic to humans, cause nervous system disorders (especially behavioral disorders), affects immune system, can cause cancer in animals, have adverse reproductive and developmental effects in wildlife, signs of growth irregularity, loss in biomass, or death to plants, in an extreme case of contamination, the number and activity of soil microorganisms may be reduced to essentially zero.