Pollution Prevention Fact Sheets: Pest Control
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This management measure involves limiting the impact of pesticides on water quality by educating residents and businesses on alternatives to pesticide use and proper storage and application techniques. The presence of pesticides in stormwater runoff has a direct impact on the health of aquatic organisms and can present a threat to humans through contamination of drinking water supplies. The pesticides of greatest concern are insecticides, such as diazinon and chloropyrifos, (CWP, 1999 and Schueler, 1995) that even at very low levels can be harmful to aquatic life. A recent study of urban streams by the U.S. Geological Survey found that some of the more commonly used household and garden insecticides occurred at higher frequencies and concentrations in urban streams than in agricultural streams (USGS, 1999). The study also found that these insecticide concentrations were frequently in excess of US EPA guidelines for protection of aquatic life. For more information see Urban Pesticides: From the Lawn to the Stream, Article 5 in The Practice of Watershed Protection.
The major source of pesticides to urban streams are home applications of products designed to kill insects and weeds in the lawn and garden. It has been estimated that an average acre of a well maintained urban lawn receives an annual input of five to seven pounds of pesticides (Schueler, 1995). Pesticide pollution prevention programs try to limit adverse impacts of insecticides and herbicides by providing information on alternative pest control techniques other than chemicals or explaining how to determine the correct dosages needed to manage pests. Lawn care and landscaping management programs often include pesticide use management as part of their outreach message.
The US EPA estimates that nearly 70 million pounds of active pesticide ingredients are applied to urban lawns each year. Table 1 compares surveys on residential pesticide use in eleven different areas of the country, broken down by insecticide and herbicide use. At first glance, it appears that pesticide application rates vary greatly, ranging from a low of 17% to a high of 87%.
Table 1. A Comparison of 11 Surveys of Residential Insecticide and Weedkiller Use
|Study||Number of Respondents||% Using Insecticides||% Using Herbicides|
|Chesapeake Bay Swann, 1999||656||21%||- -|
Kroll and Murphy,1994
Smith et al., 1994
Morris and Traxler, 1997
De Young, 1997
Knox et al., 1995
Scanlin and Cooper, 1997
|** note difference in self reported herbicide use and those that use a weed and feed product (herbicide combined with fertilizer)|
Some patterns do emerge, however. For example, insecticides tend to be applied more widely in warm weather climates where insect control is a year round problem (such as Texas, California, and Florida). Anywhere from 50 to 90% of residents reported that they had applied insecticides in the last year in warm-weather areas. This can be compared to 20 to 50% levels of insecticide use reported in colder regions where hard winters can help keep insects in check.
In contrast, herbicide application rates tend to be higher in cold weather climates to kill the weeds that arrive with the onset of spring (60 to 75% in the Michigan, Wisconsin and Minnesota surveys). For more information see Understanding Watershed Behavior, Article 126 in The Practice of Watershed Protection.
The use of integrated pest management (IPM) is a popular way for program managers to educate residents and businesses on alternatives to chemical pesticides. IPM reflects a holistic approach to pest control that examines the interrelationship between soil, water, air, nutrients, insects, diseases, landscape design, weeds, animals, weather and cultural practices to select an appropriate pest management plan. The goal of an IPM program is not to eliminate pests but to manage them to an acceptable level while avoiding disruptions to the environment. An IPM program incorporates preventative practices in combination with nonchemical and chemical pest controls to minimize the use of pesticides and promote natural control of pest species. Three different nonchemical pest control practices - biological (good bugs that eat pests), cultural (handpicking of pests, removal of diseased plants, etc) and mechanical (zappers, paper collars, etc) - are used to limit the need for chemicals. In those instances when pesticides are required, programs seek to have users try less toxic products such as insecticidal soaps. The development of higher tolerance levels among residents for certain weed species is a central concept of IPM programs for reducing herbicide use.
Education on the proper use of pesticides can and is often included in many lawn care and landscaping management programs. Most often this is in the form of informational brochures or fact sheets on pesticide use around the home or garden. These information packets include tips on identifying pest problems and selecting treatment approaches that reduce environmental impacts, less toxic pest control products if chemical control is necessary, and the proper mixing, application rates and cleanup procedures for pesticide use. Program managers can consult cooperative extension programs and university agricultural programs for more information regarding pest control techniques that are more water quality friendly.
The public perception that no alternative to pesticide use exists is probably the greatest limitation that program managers will face. Surveys tell us that the public has a reasonably good understanding about the potential environmental dangers of pesticides. Several surveys indicate that residents do understand environmental concerns about pesticides, and consistently rank them as the leading cause of pollution in the neighborhood (Elgin DDB, 1996). Even so, pesticide use still remains high in many urban areas (see Table 1). The time required for homeowners to learn more about alternative pest control techniques may also limit program effectiveness. Many residents prefer the ease of just spraying a chemical on their lawns to other pest control techniques they perceive as more time intensive and less reliable. Managers should recognize that IPM programs have their own limitations, including questions about the effectiveness of alternative pest control techniques.
Currently, a national study of the effectiveness of alternative pest control programs at reducing pesticide use and protecting water quality has not been performed. Cooperative extension and university agriculture programs across the country have performed studies of the ability of distinct alternative pest control techniques at limiting pesticide use, but a synthesis of these individual studies into a national report has not been performed. However, the need for pesticide control programs is evident from recent studies on the presence of insecticides in stormwater. Results of recent sampling of urban streams caused the USGS to conclude that the presence of insecticides in urban streams may be a significant obstacle to restoring urban streams. (USGS, 1999). Table 2 examines eight studies on stormwater runoff and insecticide concentrations and provides an example of how insecticides persist even after their use is discontinued.
Additional research done in the San Francisco Bay Region regarding diazinon use further illustrates the need for pest control programs. Results of the study show that harmful diazinon levels can be produced in urban streams from use at only a handful of individual homes in a given watershed (CWP, 1999). Due to the solubility of diazinon, current stormwater and wastewater treatment technologies cannot significantly reduce diazinon levels. The best tool for controlling diazinon in urban watersheds is through source control by educating residents and businesses on pesticide alternatives and safe application. For more information see Diazinon Sources in Runoff from the San Francisco Bay Region, Article 16 in The Practice of Watershed Protection.
An example of successful use of IPM is the Grounds Maintenance Program for the City of Eugene, Oregon. This program was started in the early 1980's and includes all the city public parks and recreation areas. The city uses a variety of IPM methods, including water blasting to remove aphids, insecticidal soaps and limited use of pesticides. The city has also adopted higher tolerance levels for certain weed and pest species that reduces the need to apply pesticides and herbicides. Since the programs inception, pesticide usage by the City of Eugene has dropped by more than 75% (Lehner et al., 1999). No exact cost savings have been calculated from the use of the IPM program, but the city turf and grounds supervisor is convinced that it saves money and has little citizen opposition.
2: Banned or Restricted Insecticides Found in Stormwater Runoff Concentrations
in µg/l (ppb)
Kroll and Murphy, 1994
Cohen et al., 1990
Hippe et al., 1994
Thomas and McClelland, 1994
Dewberry and Davis, 1989
D'Andrea and Maunder, 1994
|NA||0.5 to 2||0.1 to 2||-|
|ND = Not Detected, NA = Not Analyzed, NX= Detection only reported if they exceeded water quality standards|
The cost of educating residents on proper pesticide use varies greatly depending on the intensity of the effort. Like lawn care and landscaping programs, some cities have begun partnerships that include training of retail employees on IPM techniques. In addition, promotional materials and displays on safer pesticide alternatives are set up. The cost of staff time for training and production of materials must be included in any cost estimate. Since there are currently a number of good fact sheets on IPM and pesticide use available through cooperative extension programs, managers should consider using this source instead of creating a new one. Another way to save cost would be to utilize master gardener volunteers to help with training, both for residents and store employees.
Aveni, M. 1998. Water-wise gardener program: summary report. Unpublished data. Virginia Cooperative Extension. Prince William County, VA.
Bannerman, R. 1994. Diazinon concentrations and toxicity in stormwater ponds. Unpublished Data. Bureau of Water Management. Wisconsin DNR. Madison, WI.
California Environmental Protection Agency. 1995. Consumer Factsheet: Urban IPM. Department of Pesticide Regulation. Sacramento, CA.
Center for Watershed Protection (CWP). 1999. Diazinon sources in runoff from the San Francisco Bay region. Technical Note 106. Watershed Protection Techniques. 3(1): 613-616.
Cohen, S. S. Nickerson, R. Maxey, A. Dupuy and J. Senita. 1990. A groundwater monitoring study for pesticides and nitrates associated with golf courses on Cape Cod. Groundwater Monitoring Review. 5: 166-173.
D'Andrea, M and D. Maunder. 1994. Characterization of urban nonpoint source discharges in metropolitan Toronto.
Dewberry and Davis. 1989. Toxicity of Sediments from BMP Ponds. Final Report. Prepared for Northern Virginia Planning District Commission. Annandale, VA. 26 pp.
De Young, R. 1997. Healthy lawn and garden survey: data analysis report. Rouge River National Wet Weather Demonstration Project. Oakland County, MI. 40 pp.
Dindorf, C. 1992. Toxic and hazardous substances in urban runoff. Hennepin Conservation District. Minnetonka, MN. 98 pp.
Elgin DDB. 1996. Public awareness study: summary report. The Water Quality Consortium. Seattle, WA. 24 pp.
Hippe, D, D. Wangsness, E. Frick and J. Garret. 1994. Pesticide monitoring in the Apalachicola- Chattahoochee-Flint river basin. US Geological Survey. National Water Quality Assessment Program. Water Resources Investigation Report. 94-118. Atlanta, GA.
Knox, G., A. Fugate and G. Israel. 1995. Environmental landscape management-use of practices by Florida consumers. University of Florida Cooperative Extension Service. Bulletin 307. Monticello, FL. 26 pp.
Kroll, J. and D. Murphy. 1994. Pilot monitoring for 14 pesticides in Maryland surface waters. Dept. of Environment. Chesapeake Bay Program Technical Report. 93-020. 108 pp.
Kroupa and Associates. 1995. Westmorland lawn care survey. Milwaukee, Wisconsin. 12 pp.
Lehner, P., G. Aponte Clarke, D. Cameron, and A. Frank. 1999. Stormwater Strategies: Community Responses to Runoff Pollution. Natural Resources Defense Council, New York, NY.
Metropolitan Washington Council of Governments (MWCOG). 1983. Urban runoff in the Washington metropolitan area: Final NURP report. Department of Environmental Programs. Washington, DC. 222 pp.
Morris, W. and D. Traxler. 1996. Dakota County Subwatersheds: Residential Survey on Lawn Care and Water Quality. Dakota County, Minnesota, Decision Resources, Ltd.
National Service Research (NSR). 1998. Pesticide Usage and Impact Awareness Study: Executive Summary. City of Forth Worth Water Department. Fort Worth, TX. 44 pp.
Scanlin, J. and A. Cooper. 1997. Outdoor Use of Diazinon and Other Insecticides: Final Draft. Alameda County Clean Water Program and Alameda County Flood Control and Water Conservation District. Oakland, CA. 20 pp.
Schueler, T. 1995. "Urban Pesticides: From the Lawn to the Stream." Center for Watershed Protection. Ellicott City, MD. Watershed Protection Techniques. 2(1): 247-253.
Smith, J., S. Paul, C. Collins, A. Cavacas, and M. Lahlou. 1994 Public Survey and Pollutant Model for Prince George's County. Proceedings from Watershed '93: A National Conference on Watershed Management. Pawlukiewicz, J., P. Monroe, A. Robertson, and J. Warren (eds). EPA 840-R-94-002.
Swann, C. 1999. A Survey of Residential Nutrient Behaviors in the Chesapeake Bay. Widener-Burrows, Inc. Chesapeake Research Consortium. Center for Watershed Protection. Ellicott City, MD. 112 pp.
Thomas, P. and Scott. McClelland. 1994. NPDES monitoring--Atlanta Georgia Region. in: U.S. EPA. 1983. Results of the Nationwide Urban Runoff Project. Final Report. Vol 1. Office of Water. Washington DC.
United States Geological Survey (USGS). 1999. The Quality of Our Nation's Waters -- Nutrients and Pesticides. U.S. Geological Circular #1225. Web Site Address: water.usgs.gov.