IPM Committee Tasks: Developing IPM Plan Components: Outdoor Pesticides

Pesticide Selection

The health of school residents and the long-term suppression of pests are the primary objectives in a school IPM program. To accomplish these objectives, the program must look for non-chemical alternatives first. When these methods are not appropriate, and pesticide use is justified, pesticides with the following characteristics should be selected:

• effective against the target pest

• low acute and chronic toxicity to mammals

• degrade rapidly

• kill a narrow range of target pests

• have no or little non-target organisms

Products which possess many of these characteristics include pheromones, insect growth regulators, repellents, baits, desiccating dusts, pesticidal soaps and oils, and some botanical pesticides.

How to Select a Pesticide for an IPM Program

When contemplating the use of a pesticide, it is prudent to acquire a Material Safety Data Sheet (MSDS) for the compound. MSDS forms are available from pesticide suppliers and contain some information on potential hazards and safety precautions. 

The following criteria should be used when selecting a pesticide: safety, species specificity, effectiveness, endurance, speed, repellency, and cost.

Safety

This means safety for humans (especially children), pets, livestock, and wildlife, as well as safety for the overall environment. Questions to ask are as follows:

• What is the acute (immediate) and chronic (long-term) toxicity of the pesticide? Acute toxicity is measured by the “LD 50 ,” which is the lethal dose of the pesticide required to kill 50% of the test animals (measured in milligrams of pesticide per kilogram of body weight of the test animal). The higher the LD 50 value, the more poison it takes to kill the target animals and the less toxic the pesticide. In other words, high LD 50 = low toxicity. Chronic toxicity refers to potential health effects from exposure to low doses of the pesticide for long periods of time. Chronic effects can be carcinogenic (cancer-causing), mutagenic (causing genetic changes), or teratogenic (causing birth defects). 

• How mobile is the pesticide? Is the compound volatile, so that it moves into the air breathed by people in the building? Can it move through the soil into the groundwater? Does it run off in rainwater to contaminate creeks and rivers?

• What is the residual life of the pesticide? How long does the compound remain toxic in the environment?

• What are the environmental hazards listed on the label? What are the potential effects on wildlife, beneficial insects, fish, or other animals?

Species Specificity

The best pesticides are species-specific; that is, they affect just the group of animals or plants you are trying to suppress. Avoid broad-spectrum materials that kill many different organisms because they can kill beneficial organisms that keep pests in check. When broad-spectrum materials must be used, apply them in as selective a way as possible by spot-treating.

Effectiveness

This issue is not as straightforward as it might seem, since it depends on how effectiveness is being evaluated. For example, a pesticide can appear to be very effective in laboratory tests because it kills 99% of the test insects. But in field tests under more realistic conditions, it may also kill 100% of the pest’s natural enemies. This will lead to serious pest outbreaks at a later date.

Endurance

A pesticide may have been effective against its target pest at the time it was registered, but if the pest problem is now recurring frequently, it may be a sign that the pest has developed resistance to the pesticide or, stated otherwise, that the pesticide has lost its endurance.

Speed

A quick-acting, short-lived, more acutely-toxic material might be necessary in emergencies; a slow-acting, longer-lasting, less-toxic material might be preferable for a chronic pest problem. An example of the latter is using slower-acting boric acid for cockroach control rather than a quicker-acting but more toxic organophosphate.

Cost

This is usually measured as cost per volume of active ingredient used. Some of the newer, less-toxic microbial and botanical insecticides and insect growth regulators may appear to be more expensive than some older, more toxic pesticides. But the newer materials tend to be effective in far smaller doses than the older materials—one container goes a long way. This factor, together with their lower impact on the environment, often makes these newer materials more cost effective.

Notification and Posting

School systems have the responsibility to inform occupants when they may be exposed to pesticides. Unless it is an emergency situation, the applications should be performed when only maintenance staff are present and the building is otherwise unoccupied. Notifications of all pending treatments using a pesticide should be sent home to the students’ parents and be distributed to all school staff prior to the treatment. Schools should direct concerned parents to the school pest manager for more specific information. A voluntary registry of individuals with medically-documented problems that could be adversely affected by exposure to pesticides should be kept at each school’s office and in the pest manager’s office for special contact in emergency situations. Post all areas to be treated or that have been treated. If posting is a new practice at the school, the new policy should be explained in the context of the IPM program so that all affected parties will understand that the posting is part of a new overall effort to reduce pesticide use and not the result of new or heavier pesticide use.

Pesticide Use Guidelines

In addition to becoming informed about the characteristics of the material itself, it is important to develop guidelines to be followed each time a pesticide is used. Prepare a checklist to be used each time an application is made. The following are important items to include on the checklist:

• Make sure the pesticide is registered for use in the state. (Pesticides can be registered in some states and not in others.) What are the laws regarding its use?

• READ THE PESTICIDE LABEL. Follow its restrictions and directions for use, labeling, and storage exactly.

• If required, secure a written recommendation from a licensed pest control adviser for using the pesticide.

• Make sure that all safety equipment and clothing (e.g., neoprene gloves, goggles, respirator, hat, and other protective coverings as necessary) is available and worn when the pesticide is used.

• Verify that the person doing the application is certified and/or qualified to handle the equipment and material chosen and has been adequately trained.

• Make sure application equipment is appropriate for the job and properly calibrated.

• Confine use of the material to the area requiring treatment (spot-treat).

• Keep records of all applications and copies of MSDS sheets for all pesticides used.

• Monitor the pest population after the application to see if the treatment was effective and record results.

• Be prepared for all emergencies and compile a list of whom to call for help and the kinds of first aid to be administered before help arrives. Place the list in an accessible area near a phone.

• Dispose of pesticides properly. DO NOT pour pesticides down the drain, into the toilet, into the gutter, or into storm drains! If you are unsure about how to dispose of the pesticide, call the manufacturer or your local utility company that handles sewage and storm drains.