Chemicals that are used in landscaping include herbicides, insecticides, fungicides, and miticides. Chemical fertilizers are also used in landscaping. Of the various pesticides used, herbicides are used in the greatest amount. There is a danger of these chemicals ending up in the water supply, especially if they are applied just prior to rainfall. While professional landscapers are required to have a license before mixing or applying pesticides, homeowners are not. Each state administers a pesticide license exam, sually through their Extension Office or State Agriculture Department.

Every pesticide has a label listing the amount and identity of active ingredients. Labels also instruct the user of proper usage, target pests, and appropriate plants to be treated. They inform the user about proper clothing and safety items to be worn while mixing and using the pesticide. The label also describes proper storage and disposal of product or empty containers.

Unfortunately, many end-users of pesticide products do not read the label, or do not follow label instructions correctly. Many also do not dispose of pesticide containers properly (Latimer, J.G. et al. 1996). This results in environmental contamination.
 
Please see http://www.maine.gov/agriculture/pesticides/public/label.htm to learn more about pesticide labels.

Fertilizers and pesticides can contaminate the water supply through run-off. Nitrogen and phosphorus are the two major fertilizer ingredients contributing to water contamination problems.

Both fertilizers and pesticides used in urban settings are found in higher amounts in surface waters when application of them is followed by a major rainfall.

INTEGRATED PEST MANAGEMENT

Integrated pest management is a sustainable pest control system that dates back to the 1960s and continues to be developed through research and practice. The origins of integrated pest management can be traced to reactions to the book "Silent Spring" by Rachel Carson in 1962. Carson worked for the U.S. Fish and Wildlife service in the 1950s and became aware of controversy surrounding the hazards involved in the use of pesticides. Some chemicals used at the time have been found to be persistent in the environment and associated with dangerous conditions and diseases, including various types of cancer in humans.

Integrated pest management uses science-based resesarch to reduce and minimize the use of toxic chemicals in the production and culture of both ornamental plants and food crops. IPM involves the use of scouting and monitoring of pests, with record-keeping to indicate changes in pest populations as they occur. It includes using plants that have been selected and bred for resistance to diseases or pests, or environmental factors, such as drought, cold, or heat tolerance.

Areas of research that are considered to be a part of integrated pest management include understanding pest life cycles and targeting pesticides to disrupt the life cycle of a particular pest, genetic improvement of plants to be more resistant to diseases and insect pests, development of less toxic pesticides, including naturally occurring enemies, horticultural soaps and oils, and plant-derived pesticides, using cultural management practices to avoid pests and diseases, sanitation of ornamental plants and crops, and growing plants that are adapted to the location and situation where they will be used in the landscape.

SOURCES AND FURTHER READING

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Dreistadt, S. H., J.K. Clark, and M.L. Flint. 1994. Pests of landscape trees and shrubs:an integrated pest management guide. University of Cal. Divis. Agri. and Nat. res. Oakland, CA. 327 pp.

Embrey, S.S. and F.D. Voss. 1998. Pesticides Detected in Urban Streams during Rainstorms in King and Snohomish Counties, Washington. Water Resources Investigations Report. United States Geological Survey. No. 4098, 38 pp. (2002).

Kudsk, P. 2008. Optimizing herbicide dose:a straightforward approach to reduce the risk of side effects of herbicides. Environmentalist. 28:49-55.

Latimer, J.G. et al. 1996. Reducing the pollution potential of pesticides and fertilizers in the environmental horticulture industry I:greenhouse, nursery, and sod production. HortTech. 6(2):115-124.

Latimer, J.G. et al. 1996. Reducing the pollution potential of pesticides and fertilizers in the environmental horticulture industry II:lawn care and landscape management. HortTech. 6(3):222-232.

Lydy, M., J. Belden, C. Wheelock, B. Hammond, D. Denton. 2004. Challenges in regulating pesticide mixtures. Ecology and society 9(6):1. http://wwwecologyandsociety.org/vol9/iss6/art1. Viewed Jan. 2009.

Pedersen, T.L. 1997. Pesticide residues in drinking water. http://extoxnet.orst.edu/faqs/safedrink/pest.htm. retrieved July, 2009

Racke, K. and A.R. Leslie. 1993. Pesticides in urban environments: fate and significance. ACS Symposium Series 522. 378 pp.

Schrock, D. et al. 2000. IPM and pesticide safety, in Illinois Master Gardener Manual. Univ. Ill. Extension. champaign, IL.

Sprague, L.A., L.H. Nowell. 2008. Comparison of pesticide concentrations in streams at low flow in six metropolitan area of the United States. Environmental Toxicology and Chemistry: Vol. 27, No. 2 pp. 288–298.

Stairs, N. 1999. Riding the bio' wave. Landscape Management. Vol. 38(6):20-21.

Stewart, C.D., S.K. Branan, B.L. Sparks, J.L. Williams-Woodward, G.L. Wade, J.G. Latimer. 2002. Comparing an IPM pilot program to a traditional cover spray program in commercial landscapes. Jnl. of Economic Entomol. 95(4):789-796.

Templeton, S.R., D. Zilberman, S.J. Yoo. 1998. An economic perspective on outdoor residential pesticide use. Env. Sci. and Tech. vol. 32. no. 17:416A-23A.

White, R.S. 1971. Pesticides in the environment. M. Dekker. NY.