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Environmental and Health Issues  Less Hazardous:
Train grounds workers in integrated pest management (IPM) and how to prevent pest problems without resorting to routine spraying of herbicides, insecticides, or fungicides. Improper use or disposal (PDF, 103 KB) of some pesticides may result in contamination of water bodies, groundwater, or sewage effluent.  Water Quality:
IPM can result in fewer and less toxic chemicals contaminating surface and ground water. Pollution from runoff is called nonpoint source pollution and includes landscape sources such as storm water and agricultural runoff, and dust and air pollution that find their way into water bodies. [1]
See the Introduction for complete descriptions of these environmental and health issues.
BACKGROUND
This section covers integrated pest management (IPM) for landscapes, a broad category that includes gardens, turf, roadsides, and rights-of-way, and planted areas surrounding buildings [2]. IPM is an approach that focuses on long-term prevention of pests and is widely used by public agencies and school districts throughout California. In this section, a pest is defined as a plant or animal found in the wrong place-which means that weeds are pests as well as plant diseases, aphids, yellowjackets, or gophers. The companion section on structural IPM considers some outdoor pests [3], but its focus is on pests that enter buildings rather than those found among or on landscape plants.
Other sections within the Environmentally Preferable Purchasing Best Practices Manual overlap with this section. Compost may suppress some plant diseases and reduce the need for pesticides. Use of landscape mulch helps manage weeds, reducing or eliminating herbicide use. Mulch adds nutrients to soil, leading to healthier plants, and reduces the need for fertilizers and pesticides.
Are herbicides considered pesticides? A pesticide (PDF, 86 KB) is any substance intended to control, destroy, repel, or attract a pest. Pesticides include herbicides, fungicides, insecticides, rodenticides, and even naturally occurring, pest-destroying organisms such as Bacillus thuringiensis. Botanical products that contain food-grade ingredients such as clove or mint oil are pesticides. Some fertilizers-for example, the weed-and-feed type-are considered pesticides and have a label with a United States Environmental Protection Agency (U.S. EPA) registration number.
In-house grounds workers vs. contractors. State agencies in California use both in-house and contracted grounds workers. The Department of Pesticide Regulation (DPR) regulates the landscape maintenance industry, and certifies or licenses those who apply pesticides for hire. Any landscape maintenance or pest control contractor who applies pesticides (including herbicides) must have a valid business license issued by DPR. Whether in-house or contractor, the applicator must hold a certificate (Qualified Applicator Certificate or QAC) or license (Qualified Applicator License or QAL) [4]. In addition, some landscape professionals are agricultural pest control advisers (PCA), who may offer recommendations on pesticide use for parks, golf courses, and rights-of-way. For more detailed information on licensing, see DPR's Licensing and Certification Web page.
IPM Practices in California's Schools. Since 1993, the California Department of Pesticide Regulation (DPR) has worked with school districts in the State to provide information about IPM. During this time, a few innovative districts developed their own IPM programs. In the 1990s, a few herbicide-misuse episodes took place in California schools, resulting in the Healthy Schools Act of 2000 (PDF, 20 KB). This new law put into place right-to-know requirements such as notification, posting, and record keeping for pesticides used at California's K-12 public schools. The law also encourages use of IPM practices that are safer for school environments, ultimately reducing children's exposure to pesticides.
ENVIRONMENTAL AND HEALTH ISSUES
Pesticide toxicity. Two different pesticide products may contain the same active ingredient, the part of the pesticide that kills the pest, but yet differ in toxicity. Acute toxicity results from a single dose or short-term exposure of a substance, and chronic toxicity by repeated small doses over a long time. U.S. EPA assigns signal words (danger, warning, caution) by level of acute toxicity.
Pesticide exposure. People can be exposed to chemicals by inhalation or through their skin, mouth, nose, or eyes. Exposure is intensified when a chemical volatilizes (evaporates), which is why most reported pesticide mishaps outdoors result from applications of liquid pesticides. The volatilizing pesticide doesn't have to be toxic to cause an allergic reaction or asthma-even some botanical products can cause problems if label directions are not followed.
Contamination of water. When lawns or plants are treated with pesticides, irrigation or rain may convey the pesticides from concrete or asphalt into storm drains, which in most of California drain untreated directly to surface water. Studies have shown that urban sources of pyrethroid insecticides can enter surface water such as creeks and streams, where minute quantities kill native aquatic organisms. Pyrethroids are popular as commercial and residential perimeter sprays (see Structural IPM), and are also used in some plant sprays and weed-and-feed products. Examples include products containing bifenthrin, deltamethrin, lambda cyhalothrin, and permethrin. The active ingredients in herbicides, or even inert ingredients that help the herbicide stick to plant leaves, may also contaminate ground water (PDF, 100 KB) and surface water [5]. As protection for endangered salmon and steelhead habitat, a 2004 federal court order established buffer zones adjacent to water bodies in California, Oregon, and Washington for application of 33 different pesticidal active ingredients, including several herbicides. COMPONENTS
An IPM program for landscaping combines several steps to limit weed growth and prevent infestations of insects, rodents, and other pests. Here are the steps recommended by landscape experts:
- Prevent pest problems by designing a landscape that's unappealing to pests. For example, plant pest-resistant or well-adapted plant varieties such as native plants. Make sure that plants are matched to the irrigation system or climate. Consider the specifics of your situation, because suppressing one pest may increase another. Thick ground covers will prevent weed growth, but they're also ideal rat habitat. Composting will reduce green waste, but in areas where rats thrive, you'll have to enclose the compost. Mowing strips and underlayments [6] can reduce herbicide use because weeds no longer grow in inaccessible areas-under benches, for instance-and can easily be mowed (see mechanical control below).
- Identify the pests and symptoms so you know how to proceed. You wouldn't want to spray a rosebush covered with hover fly larvae, which resemble small green slugs and devour aphids, not plants. Common pest problems include insects, mites, snails and slugs, plant diseases, vertebrates, abiotic disorders such as nutrient deficiencies, weeds, and nematodes.
- Survey (monitor) for pests on a regular basis. Look for conditions that encourage pests such as chronic under- or overwatering, overfertilizing, incorrect pruning such as topping, and plant injuries.
- Decide what's an acceptable level for each pest and at what point you need to take action. For example, you might allow aphids to build up on plants on an embankment, knowing that natural enemies will soon follow and eliminate most of the aphids. However, for aphids that infest trees in parking lots, walkways, or along thoroughfares, and have no obvious natural enemies, you would want to take action as soon as possible. (See example of Asian woolly hackberry aphid below.)
- Use practices that effectively manage the pest, and that pose the least risk to human health and the environment. Some of these practices are mentioned below.
Types of Preventive Practices
Cultural control includes selection of disease-resistant plant varieties; proper irrigation, fertilization, and pruning; and planting at the right time of year.
When you use a physical control you change physical conditions-temperature, light, or humidity-to prevent pest problems. Examples include landscape fabric to shade out weeds and pruning dense plants to allow better air circulation and thus prevent disease.
With mechanical control, pests are managed through manual labor or simple objects, devices, or equipment such as using handheld propane flaming units that cook weeds, installing mowing strips and underlayments, and fastening copper bands around tree trunks or planters to exclude snails and slugs.
Biological control is the use of beneficial organisms (also known as natural enemies) to reduce pest populations. Beneficial organisms include parasitic insects (usually tiny wasps) [7] and predaceous insects, mites, and spiders; bats; birds; amphibians and reptiles. Just about every pest has at least one natural enemy that keeps its population in check. Trouble arises when a pest escapes its natural enemies by arriving in a new environment. One example is the ash whitefly. In 1988, this whitefly spread throughout California and soon covered urban trees such as ash and ornamental pear. Scientists from the California Department of Food and Agriculture traveled to the ash whitefly's ancestral home in Italy, where they located a wasp that readily parasitizes immature ash whiteflies. Within two years of its release, the wasp drastically reduced the ash whitefly population. Biological control is superior to foliar pesticide sprays for managing ash whitefly and similar pests such as scale insects and mealybugs.
Chemical control may be necessary if an emergency arises or a pest population must be reduced quickly. Reduced-risk pesticides don't endanger living organisms or the environment. Ideally, they break down easily, have narrow specificity, do not kill natural enemies, and do not volatilize around people. Examples of reduced-risk pesticides used for landscaping include the microbial insecticide, Bacillus thuringiensis, herbicides and insecticides that contain mint or clove oil, potassium bicarbonate for plant mildews, horticultural oil for sucking insects, and if absolutely necessary, spot-sprayed conventional herbicides.
What about emergencies? What if, despite excellent preventive care, there's a sudden infestation of mystery bugs on trees surrounding a parking lot? You would want to make sure you correctly identify the pest and inspect other trees for the bugs.
In 2002, the Asian woolly hackberry aphid, previously unknown in California, suddenly blanketed Chinese hackberry trees in many parts of the state. Honeydew from the aphids' feeding dripped onto cars and made a sticky mess on asphalt and pavement. It took two growing seasons before experts figured out good management strategies. They recommend first identifying the aphid to avoid confusing it with the citricola scale, which also produces honeydew. Next, they recommended using cultural controls such as limited irrigation and fertilizer-and when necessary, soil drenches of a reduced-risk systemic insecticide. What about biological control? So far, natural enemies for the hackberry aphid haven't been introduced into California.
LAWS AND GUIDELINES
California
Statute
Existing State law (AB 2472, Chapter 242, Statutes of 2003) (PDF, 9 KB) provides that it is the policy of the State to protect public health and safety in a manner that complements sustainability as an extension of resource conservation. It also states that the safe handling, reduction, or elimination of pesticide use in state buildings and on state lands is an important step in providing all state employees and members of the public with a safe, healthy environment.
Since 1993, the California Department of Pesticide Regulation (DPR) has worked with school districts in the State to provide information about IPM. During this time, a few innovative districts have developed their own IPM programs. In 2001, the enactment of the Healthy Schools Act of 2000 (PDF, 20 KB) put into place right-to-know requirements such as notification, posting, and record keeping for pesticides used at California's K-12 public schools. The law also encourages use of IPM practices that are safer for school environments, reducing children's exposure to pesticides. Misapplications of herbicides spurred this legislation, so many districts are interested in herbicide alternatives for gardens and turf.
Ordinances, Resolutions, Programs, and Policies
Since 1995 several California cities and counties have passed ordinances and established policies that require the use of IPM on public property.
The City of Santa Monica developed a structural IPM program in 1995 and a landscape IPM program in 1998. Pesticides used on city property are regulated. Early efforts eliminated broadcast applications of herbicides in all city parks and sports fields, and pilot pesticide-free zones in certain city rights-of-way and parks were established. An ordinance passed in 2004 requires less runoff to Santa Monica Bay through increased permeable surfaces such as found in landscaped areas.
In 1996, the City and County of San Francisco enacted an ordinance to regulate and reduce the use of pesticides on city property by city departments, agencies, and contractors. The ordinance prohibits use of certain pesticides including carcinogens and reproductive toxins, and requires the posting of notices and contact information to inform the public whenever a pesticide is used on city property. See Success Stories for details about specific pest management practices.
The City of Santa Barbara (PDF, 358 KB) adopted a resolution in June 2003 that emphasizes planning, design, and installation to minimize pest problems of landscapes, facilities, or road rights-of-way. Each City department must appoint an IPM coordinator who reviews project plans to make sure that the design uses IPM strategies. The design considers soil types, grading and slope, the water table, drainage, proximity to sensitive areas, selection of vegetation, and vector-control issues [8]. City grounds designers, planners, managers, crews, and their contractors give priority to IPM strategies when designing new and renovating existing landscaped areas.
Federal
In 1994, a presidential memorandum, "Environmentally and Economically Beneficial Practices on Federal Landscaped Grounds," emphasized using regionally native plants and landscape practices that conserve water and prevent pollution. According to the memorandum, pollution prevention could be achieved by reducing fertilizer and pesticide use and using IPM practices, recycling green waste, and minimizing runoff.
PERFORMANCE
On golf courses, where aesthetic standards are high, elimination or even reduction of herbicides is difficult. Yet, at the popular Presidio Golf Course in San Francisco, grounds staff spray compost tea, a mixture of compost and water, onto golf course greens and landscapes in place of synthetic fertilizers. The healthier turf and landscape are then better able to resist disease. Since 2000, the golf course has steadily reduced overall pesticide use and currently uses approximately 98 percent less pesticide than private Bay Area golf courses. [9]
Santa Barbara County's Parks Department reduced herbicide use by mulching with wood chips and using mechanical practices such as mowing and weed whipping. The Department purchased a device that kills weeds by squirting them with water heated to 2,800 degrees Fahrenheit . This device has been used in several County Park open spaces, and although time-consuming to use, effectively manages weeds.
AVAILABILITY
California does not yet provide special certification for landscape maintenance businesses with staff trained in IPM practices, but in 2007, draft standards will form the basis of a pilot certification program for landscape IPM. Refer to Specifications for tips on selecting knowledgeable and experienced IPM professionals.
COST
Most public agencies that have switched to an IPM approach have reduced their costs after initially paying more during a transition period. IPM can reduce costs by eliminating regular pesticide spraying, but those costs are redirected toward preventive practices, such as training employees, inspecting for pests, and investing in landscaping improvements. Improving irrigation systems or purchasing new equipment may cost more up front, but will lower costs in the long run.
When gardeners at Seattle University (PDF, 3,520 KB) stopped using landscape pesticides in 1986, they installed ground cover plants to outcompete weeds. After three years, the ground covers grew in and saved the 48-acre university $1,300 annually, mostly by reducing costs of chemical inputs, soil loss due to erosion, and equipment maintenance. The university continues to use a wide range of innovative practices.
The California Department of Transportation (Caltrans) compared costs for various roadside treatments along road edges (see Success Stories below). Planting native vegetation along road edges or medians costs up to tenfold less ($1-$10/m˛) than installing asphalt concrete pavement ($20-$80/m˛), aggregate base ($10-$35/m˛), patterned concrete ($35-$80/m˛), or stamped asphalt ($25-$45/m˛). In transitional, rural, and natural areas where native vegetation is suitable, plants will last 15 to 20 years.
SPECIFICATIONS
California
Sample Language
Thorough specifications help eliminate low bidding by firms unwilling to use an IPM approach. The City of Santa Monica requested vendors to demonstrate their qualifications by submitting the following information:
- Résumés of service technicians or relevant subcontractors who will be on site to service the account or supply technical support.
- A description of experience in the design or implementation of IPM programs (including specifics about the types of equipment and products used to control pests).
- A list of clients receiving IPM service from the company.
- A description of training provided to clients.
- A summary of all regulatory inspections and violations in the past five years and the company's response to any violations.
Examples
Alameda County supports a Bay-Friendly Landscape Program that ideally mimics natural systems through recycling of water, debris, and nutrients. Bay-Friendly gardening emphasizes local climate and soil conditions, and uses plants adapted to those conditions. The landscape specifications follow the Bay-Friendly Landscape principles and practices to specifications for bidding and contract development.
Santa Barbara County's IPM Strategy (PDF, 177 KB) advises the interdepartmental grounds management committee to review and revise procurement practices.
Various cities and counties in California. During 2006, cities and counties in the San Francisco Bay area and part of the Sacramento Valley will compile sample contract language for structural and landscape IPM that includes requests for proposals or qualifications, and specifications.
VENDORS
See Availability
SUCCESS STORIES California Department of Transportation (Caltrans) - Roadside Management Toolbox
In 1992, Caltrans adopted an integrated vegetation management (IVM) program for its 15,000 miles of highways and 230,000 acres of right-of-way land. The IVM program began as a way to cut down on manual, mechanical, and chemical highway maintenance for both economic and environmental reasons. The Roadside Management Toolbox combines treatment categories such as road edges and medians with treatment details that include irrigated vegetation, native vegetation, fiber and rubber weed-control mats, and gravel and organic mulch.
City and County of San Francisco, California
As part of San Francisco's Pesticide Program, City staff receive extensive training in alternative practices for managing pests, and use tools such as handheld flaming units that cook weeds, containerized baiting systems, insect growth regulators, weed fabric, and mulches. One of San Francisco's departments, the San Francisco Public Utilities Commission, manages extensive watershed right-of-way lands across Northern California. As part of the Commission's comprehensive IPM program for steep areas in the watershed, goats clear away poison oak and other weeds. The Department of Public Works plants native wildflowers in the median strips that divide San Francisco streets. The wildflowers outcompete weeds until permanent plantings are installed.
Marin County, California
Successful implementation of IPM programs by Marin County departments has resulted in significant reduction in pesticide use. The County Department of Agriculture established a Weed Management Area where pest weeds are removed mechanically, and biological control agents are released to keep weed populations low.
State of Washington-Seattle University
In 1979, Seattle University adopted a landscape IPM program and has successfully maintained the 48-acre campus since 1986 without using any pesticides. Grounds staff use a combination of practices that promote soil fertility. Other practices include appropriate plant selection, using nonchemical weed suppression, mulching, cycling nutrients, grasscycling, using mycorrhyzal fungi, fertilizing with compost and compost tea, and releasing beneficial insects.
RESOURCES AND WEBSITES
Pesticides and IPM
California Department of Pesticide Regulation (DPR)
Sacramento, California
(916) 445-4300
Central Contra Costa Sanitary District. 2004. Pesticides and Water Quality (PDF, 103 KB). Our Water Our World, 2-page fact sheet.
Pest Management References
See University of California IPM Online Resources: How to Manage Pests: Pests in Landscapes, Gardens, and Turf.
Costello, Laurence. 2003. Abiotic Disorders of Landscape Plants. University of California Division of Agriculture and Natural Resources. Oakland, Calif. Provides information on disorders caused by environmental, physiological or other nonbiological factors.
Dreistadt, Steve. 2004. Pests of Landscape Trees and Shrubs, 2nd edition. University of California Division of Agriculture and Natural Resources. Oakland, Calif. Comprehensive guide to IPM of landscape plants.
Habitat Restoration
Native plants
U.S. EPA. 1997. A Sourcebook on Natural Landscaping for Public Officials. A guide to replacing conventional lawns and gardens with natural landscaping. Focuses on Great Lakes and Midwestern United States. Project initiated because of 1994 presidential memorandum, "Environmentally and Economically Beneficial Practices on Federal Landscaped Grounds."
Rubissow Okamoto, A. 2005. Bringing back native grasses. CalFed Bay-Delta Science Program.
Sawyer, J.O., Jr. and T. Keeler-Wolf. 1997. A Manual of California Vegetation. Published as a book and an online version by the California Native Plant Society and botanists from academia, conservation organizations, environmental consulting companies, and state and federal agencies.
California State Parks. 2002. Vegetation mapping: A primer for the California State Park System (PDF, 166 KB). A 54-page guide prepared by Roy A. Woodward that introduces State Park planners and ecologists to vegetation mapping.
Roadsides
Although hedgerows often serve as buffers between roadsides and farmland, they are appropriate for other borders, and help suppress weeds, control erosion from wind and water, and attract beneficial insects. Another useful guide is Hedgerows for California Agriculture-A Resource Guide (2004) by Sam Earnshaw, Community Alliance with Family Farmers.
Invasive plants
Weed Management Areas, California Department of Food & Agriculture.
Mowing Strips and Underlayments
Ard, Jeff. 1999. Fundamentals of a Low-Maintenance, Integrated Pest Management Approach to Landscape Design. IPM Associates, Inc.
Golf Courses
United States Golf Association. The environmental principles for golf courses in the United States. A set of principles developed by a group of leading golf and environmental organizations that advocate environmental responsibility in golf course planning and siting, design, construction, maintenance and facility operations.
Audubon International - Environmental Management Practices for Golf Courses. 2006. The Audubon Cooperative Sanctuary Program for Golf Courses helps superintendents and golf industry experts establish environmentally sustainable golf courses. A checklist describes how to set up wildlife habitat, establish native plant communities, and implement IPM practices.
GLOSSARY
QAC or Qualified Applicator Certificate. Silver card. Any person who uses or supervises the use of federally restricted use pesticides or State restricted materials for any purpose or on any property other than that provided by the definition of "private applicator" [Title 3, California Code of Regulations (CCR), section 6000]. This certificate is also required by anyone who is in the business of landscape maintenance and performs pest control that is incidental to such business. In this situation, the Qualified Applicator Certificate (QAC) holder would have to possess the Landscape Maintenance Pest Control Category on their certificate, and obtain a Maintenance Gardener Pest Control Business License.
QAL or Qualified Applicator License. Brown card. Any person who supervises the pesticide application (restricted-use and/or general-use pesticide) made by a licensed Pest Control Business and is responsible for the safe and legal operation of the pest control business [California Food and Agricultural Code (FAC) sections 11701-11709] or any person who uses or supervises the use of a federally restricted-use pesticide or state-restricted material for any purpose or on any property other than that provided by the definition of "private applicator" (3 CCR section 6000).
PCA or Agricultural Pest Control Adviser. Green card. An Agricultural Pest Control Adviser License is required by any person who offers a recommendation on any agricultural use, who holds himself or herself forth as an authority on any agricultural use, or who solicits services or sales for any agricultural use (FAC sections 11410, 11411). Agricultural use includes commercial production of animals or plants (including forests), parks, golf courses, cemeteries, roadside, power line rights-of-way, and nurseries. Any landscape architect who includes pesticide use recommendations in landscape architectural plans must be licensed as a PCA, unless the recommendations are made for houses, offices, shopping centers, and other similar settings. PCA licensing is required for pesticide use recommendations for parks and recreational areas, golf courses, cemeteries, parkways, highways, and other similar settings.
[1] California Water Resources Control Board, Water Quality, Accessed on 10-6-06. Available at: http://www.waterboards.ca.gov/
[2] This section also includes fencelines, sidewalks and walkways, parking islands, landscape boxes and beds, landscaping adjacent to buildings, hardscaped play surfaces, parking areas, and creeks and riparian restoration areas.
[3] The oriental cockroach is a structural pest that lives outdoors. This roach, widespread in California, makes its home in damp, underground utility and valve boxes. The roaches are usually managed by pest control operators rather than landscape professionals.
[4] An exception to this rule exists in public schools where grounds staff do not have to be certified or licensed unless they apply federally restricted-use pesticides such as aluminum phosphide . Only a person holding a QAC or QAL plus a permit issued by the county agricultural commissioner may apply State-listed restricted-use pesticides. Some school districts require that all pesticide applications be supervised or performed by certified or licensed applicators. A pest control business license is required of any person or company performing pest control for hire.
[5] A study published by Rick Relyea of University of Pittsburgh in 2005 showed tadpole mortality from an inert ingredient, polyethoxylated tallow amine (POEA), in some formulations of the herbicide, glyphosate. Inert ingredients are not listed on the pesticide label, but make up most of the pesticide product. POEA serves as a surfactant, helping the sprayed material penetrate leaves.
[6] Mowing strips are hard surfaces such as concrete or brick that border turf and enable mowers to maneuver more freely. Underlayments refer to a hard surface underneath or surrounding the base of a landscape feature located in a turf area (e.g., benches, tables, signs, bicycle racks, fencelines).
[7] In the insect world, the word "parasite" can mean either true parasites such as fleas, or parasitoids, which include thousands of species of tiny wasps. (These wasps do not resemble yellowjackets or hornets, and they don't sting people or any animal besides their host.) Parasitoids ultimately cause the death of their host by laying one or more eggs in its body. As the young parasitoid matures within the host, it eats the host from the inside out and finally emerges as an adult. A number of variations on this theme exist-for example, some parasitoids lay their eggs in their hosts' eggs, while others pursue the larval or adult stage.
[8] For example, the tendency of a marshy area to encourage mosquito breeding.
[9] http://www.presidio.gov/Projects/Sustainability/IPM/ (offline). Accessed Summer/Fall 2006.
Special Note: Portions of the Environmentally Preferable Purchasing Best Practices Manual were borrowed or adapted from the Environmentally Preferable Purchasing Guide published by the Solid Waste Management Coordinating Board of Minnesota.
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