F E A T U R E   A R T I C L E

Increasing public awareness and concern about the real or perceived dangers of chemical pesticides has placed park managers between a rock and a hard place.

Many centuries ago, Chinese farmers observed that ants were preying on caterpillars, beetles and leaf-feeding bugs within their citrus orchards. The farmers learned that ants were killing other bugs that damaged their produce. So, they decided to search for the nests of these ants in the countryside. After the ants and their papery nests were introduced into the orchards, the control of pests greatly improved. The farmers even devised bamboo runways between the citrus trees to help the ants move easily from tree to tree. These efforts to increase the number of ants in the orchard and improve their efficiency as predators are the first recorded occurrences of the intentional use of natural predators to control insect pests.

The science of pest control certainly has become more sophisticated since then, thanks to increased knowledge and understanding of insect pests and technological advances. Today, we rely more on chemical means of pest control. The chemical industry has developed products that are effective, relatively inexpensive, easy to use, and have long shelf lives. In other words, they offer that ideal combination of low cost and convenience.

Public facilities and parks, along with most other sectors of our society, have used and benefited from these pest control products for many years. From their first introduction, however, there have been questions about their safety. Most of these concerns were dismissed as unproven and contrary to society's desire to control the costs associated with pest damage. In fact, some products originally touted as "safe and effective" later were determined to be harmful to people and to the environment. DDT is the best known example.

We also now know that the long-term effectiveness of chemical pesticides is often limited. Insect populations often develop resistance to specific pesticides after years of overuse, requiring the use of something new or more toxic. In recent years, increasing public awareness and concern about the real or perceived dangers of chemical pesticides has placed park managers between a rock and a hard place. How do we address both the public desire for well-maintained parks and facilities and the public's concern about exposure to hazardous chemicals? Increasingly, park agencies have turned to "integrated pest management" or IPM and the use of bio-pesticides to treat pest insects in parks and buildings and weeds in park landscapes. These concepts are not new, as illustrated by the Chinese history lesson. For many profes-

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FEATURE ARTICLE

sionals trained in the use of chemical pesticides and convinced of their effectiveness, however, some of these new ideas originally seemed far-fetched, unproven and ineffective. They are, in fact, based on sound science and have proven their effectiveness for many years.

What Is IPM?

Integrated pest management can be described as a careful and deliberate approach to pest control. Traditionally, farmers, land managers and facility maintenance personnel were taught to apply pesticides as part of a regular maintenance schedule, whether or not there was a problem. IPM provides a less costly and less toxic alternative to the "scorched earth" policy of traditional chemical pest control. Pesticides are used only when necessary and only in the quantities required to treat the existing problem. Also, the goal is to identify a potential problem long before it becomes a major problem. This allows solutions to be small-scale and targeted. A successful IPM program includes:

• regular monitoring for problems;

• accurate identification of those problems as well as their root causes;

• the use of management strategies that employ a range of effective remedies, starting with the least toxic;

• timely implementation of appropriate management strategies; and

• evaluation of the results.

Integrated pest management provides a less costly and less toxic alternative to the "scorched earth" policy of traditional chemical pest control.

Developing and implementing a successful IPM program takes time, proper planning, some re-education of staff, and commitment from top administrators. It also requires a greater awareness and understanding of potential pest problems and some additional staff time to monitor facilities and parks. When outside contractual services are used for pest control, it is important that they clearly understand your goals. They should know that they are on-call only, are expected to provide you with accurate diagnoses of problems, should consult with you before any treatments are initiated, and provide you with detailed information on the chemicals, quantities and concentrations they do use.

IPM programs are in common use by park and facility managers and are considered best practices in most circles. In addition to reducing the amount of pesticides used, they can cut costs considerably and can be tailor made to fit the needs and resources of the agency.

Taking the Path Less Toxic

While the use of an IPM program can reduce the use of pesticides within parks and facilities, it does not totally eliminate them. And there have been calls to do just that in some communities recently. In several well-publicized cases, school districts and park districts have been challenged by residents who are chemically sensitive. These are individuals who have an allergic sensitivity to any contact with certain chemicals, most notably those that contain petroleum products (which includes most chemical pesticides).

In 1992, the Chicago Tribune reported on one suburban woman's battle against her village board over the spraying of pesticides to kill tree-killing gypsy moths. She claimed her chemically sensitive 14-year-old son would need to leave town to avoid medical complications. Also in the early 1990s, a Schaumburg woman convinced both the local school district and park district boards to closely examine their use of pesticides and adopt IPM programs in order to protect the health of her and her children.

Challenges by these individuals have resulted in many public agencies totally eliminating the use of certain products and/or adopting IPM programs. Another solution has been to develop notification systems so that chemically sensitive individuals are notified prior to the application of pesticides to an area and can avoid the exposure.

Along with the rise in public awareness of the dangers of pesticides and other industrial chemicals has come the development of many new products touted as "safer" and "more natural." This list includes:

• products that contain botanical insecticides (derived from plants) such as cirronella, pyrethrums, and nicotine;

• other natural substances such as diatomaceous earth (a type of powdered limestone) and borax;

• chemical attractants which mimic insect pheromones (insect "odors") and traps, such as fly paper; and

• mild chemical pesticides such as insecticidal soaps and dormant oils.

While many of these products are indeed safer than most chemical pesticides, they are sometimes limited in their effectiveness and can cost more. It is important to recognize that any substance, whether petroleum-based or naturally derived, has some degree of toxicity,

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and there will always be some people who have sensitivities to them.

In other words, no pesticide is completely non-toxic. They kill pests, so they must have some effect on other living things, including people. For park managers, the most practical approach may be to search for those naturally derived products with proven effectiveness and incorporate them into an IPM program.

Imitating Nature with Bio-pesticides

The only completely non-toxic pest control method is the use of bio-pesticides, or biological control. Simply defined, biological control is the intentional manipulation of populations of beneficial creatures in order to reduce the numbers of pests or amount of damage. These beneficial creatures—known as natural enemies—are sometimes imported from the pest species' place of origin (an especially common strategy when dealing with introduced pests).

In other situations, it makes more sense to manage an area in such a way that existing beneficial species are conserved so that they can do their job. Sometimes, this can be accomplished simply by halting the use of chemical pesticides, since these are generally non-selective and kill the beneficial species as well as the pests. At other times, the existing population of natural enemies must be augmented with additional beneficial species in order to achieve the desired results. While intentional and designed by humans, biological control imitates nature. Populations of all creatures are naturally controlled by interactions with predators and disease. In so doing, pests are not eliminated (the sometimes stated but never achieved goal of chemical pesticides) but reduced to acceptable levels.

The agents of biological control come in many shapes and sizes, including microscopic bacteria, insects, and even mammals. Employing a house cat to control mice and the use of ladybugs in a greenhouse to control aphids are examples of predators, the classic form of biological control. Insects are not the only pests that can be targeted by this form of biological control. The Galerucella beetle has been enlisted in recent years to fight purple loosestrife, a highly invasive plant of natural wetlands. This natural enemy of purple loosestrife was found living in the plant's native European wetlands, but had not been present here before.

The use of parasites such as Trichogramma flies, which lay their eggs on the larva of certain pest insects, is a less well-known form of biological control. When the eggs

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hatch, the young flies burrow into the host insect and kill it.

Pathogens, which can include bacteria, viruses, fungi, nematodes, and other microorganisms that cause diseases, represent the final type of control agent. The best known example is the bacterium commonly known as "Bt." Many different strains of Bt have been developed to achieve control of specific pests such as gypsy moths and Colorado potato beetles.

Unlike IPM, biological control is still considered an alternative technology by most people. Its lack of widespread acceptance is understandable in some respects.

Bio-pesticides generally cost more than traditional approaches, possess a less stable shelf life and require periodic re-applications. Biological control also requires that we tolerate the presence of some insects or weeds—including the pests we're trying to control—within the spaces we claim as our own (our homes, offices, schools, as well as our created park landscapes). This is something most public agencies would find hard to justify given the high value that our society places on cleanliness and appearance. It does, however offer an effective way out of the chemical dilemma faced by parks professionals.

If part of our mission is to promote healthy lifestyles and provide a healthy environment for our patrons, we cannot dismiss its potential benefits. The orchards we tend in our day-to-day work can only become more productive and the fruits of our labors sweeter. •

DAVID BROOKS is the manager of conservation services for the Schaumburg Park District.

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