Integrated Pest Management

Practicing Integrated Pest Management (IPM) can reduce the quantity of chemical pesticides entering the environment and can save money. IPM is based on taking preventive measures, monitoring the crop, assessing the pest damage, and choosing appropriate actions. Many different tactics are used in IPM, including cultural practices, biological control agents, chemical pesticides, pest-resistant varieties, and physical barriers.

Goals of This Chapter

Understand the benefits and components of integrated pest management.
Learn what is meant by the term economic threshold.
Learn the three types of control used in IPM.

IPM Defined

Integrated Pest Management (IPM) is a process consisting of the balanced use of cultural, biological, and chemical procedures that are environmentally compatible, economically feasible, and socially acceptable to reduce pest populations to tolerable levels.

Integrated means that many strategies are used to avoid or solve a pest problem. These strategies come from different disciplines, such as disease information from plant pathologists, weed information from agronomists, and insect information from entomologists.

Pests are unwanted organisms that are a nuisance to man or domestic animals, and can cause injury to humans, animals, plants, structures, and possessions.

Management is the process of making decisions in a systematic way to keep pests from reaching intolerable levels. Small populations of pests can often be tolerated; total eradication is often not necessary.

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Why Practice IPM?

You might be wondering why you should even consider IPM when chemical pesticides so often succeed at controlling pests. Here are some reasons for having a broader approach to pest management than just the use of chemicals.

Keep a Balanced Ecosystem. Every ecosystem, made up of living things and their non-living environment, has a balance; the actions of one creature in the ecosystem usually affect other, different organisms. The introduction of chemicals into the ecosystem can change this balance, destroying certain species and allowing other species (sometimes pests themselves) to dominate. Beneficial insects such as the ladybird beetle and lacewing larvae, both of which consume pests, can be killed by pesticides, leaving few natural mechanisms of pest control.

Pesticides Can be Ineffective. Chemical pesticides are not always effective. Pests can become resistant to pesticides. In fact, some 600 cases of pests developing pesticide resistance have been documented to date, including common lamb's-quarter, house flies, the Colorado potato beetle, the Indian meal moth, Norway rats, and the greenhouse whitefly. Furthermore, pests may survive in some situations where the chemical does not reach pests, is washed off, is applied at an improper rate, or is applied at an improper life stage of the pest.

IPM Is Not Difficult. Although some of the terms and ideas may be new to you, practicing IPM is not difficult. Believe it or not, you will have done much of the "work" for an IPM approach if you've figured out the problem (the pest), determined the extent of the damage, and decided on the action to take. These steps are the same ones used in IPM.

Save Money. IPM can save money through avoiding crop loss (due to pests), and avoiding unnecessary pesticide expense. For example, onion growers who followed IPM recommendations in 1987 saved more than $23 an acre in insecticide costs. Golf course superintendents who replace fungicides with organic fertilizers or composts can save up to $1500 every time a fungicide is not applied. Applicators are able to save on sprays because the calendar is not the basis for spraying; the need is.

Promote a Healthy Environment. We have much to learn about the persistence of chemicals in the environment, and their effect on living creatures. However, more cases of contaminated groundwater appear each year, and disposal of containers and unused pesticides still pose challenges for applicators. Even though long-term documentation on the effects of all pesticides is still unavailable, it is generally agreed that fewer pesticides means less risk to surface water and groundwater, and less hazard to wildlife and humans.

Maintain a Good Public Image. Recent public outcry about the use of growth regulators and the presence of pesticide residues on produce has heightened pesticide applicator awareness of the level of public concern about chemicals. Consumers are pressuring food stores, which in turn are pressuring producers, for produce that has been grown with as few pesticides as possible. Growing food under integrated pest management can help allay public concerns. Structural pest control professionals can suggest improvements in housekeeping or structural modifications as substitutes for chemical control.

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The Basic Steps of IPM

All of the components of an IPM approach can be grouped into four major steps. The first step is taking preventative measures to prevent pest buildup, the second is monitoring, the third step is assessing the pest situation, and the fourth is determining the best action to take.

Preventative Measures

Many IPM practices are used before a pest problem develops to prevent or stall the buildup of pests.

Cultural Controls are those that disrupt the environment of the pest. Plowing, crop rotation, removal of infected plant material, sanitation of greenhouse equipment, and effective manure management are all cultural practices that are employed to deprive pests of a comfortable habitat. The management of urban and industrial pests has improved when sanitation programs have been improved, pest harborages eliminated, garbage pickup frequency increased, or when lights are installed that do not attract insects.
Structural Modifications - by preventing support timbers from soil contact, damage from several different wood destroying pests can be avoided. Wood absorbs moisture and is more susceptible to attack by carpenter ants and termites when in direct contact with the soil.

Construction Site Sanitation - removing tree stumps and lumber scraps from construction sites, which are prime food sources for subterranean termites, can prevent problems in the future.
Biological Controls - using natural enemies (biological control agents) to keep pests in check can be put into place before pest problems increase. Examples of biological control agents are beneficial mites that feed on mite pests in orchards, the milky spore disease that kills harmful soil grubs, and Encarsia formosa , a wasp that parasitizes the greenhouse whitefly. Many biological control agents are commercially available.
Physical Barriers such as netting over small fruits and screening in greenhouses can prevent crop loss. Physical barriers are important in termite, house fly, and rodent control.
Use of Pheromones (natural insect scents) has become widely used in pest management. Sometimes a manufactured "copy" of the pheromone that a female insect emits to attract mates can be used to confuse males and prevent mating. This technique is used in curbing damage from the grape berry moth.
Pest-Resistant Varieties are those that are less susceptible than other varieties to certain insects and diseases. Use of resistant varieties often means that growers do not need to apply as many pesticides as with susceptible varieties. Potato growers control the golden nematode by planting resistant cultivars. Apple growers can save up to eight fungicide applications a year by growing Liberty and Freedom cultivars, which resist diseases. Farmers growing alfalfa and wheat keep several pests at bay by planting resistant varieties.

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Once a pest manager has taken precautions to prevent pest infestations, it is important to watch regularly for the appearance of insects, weeds, diseases, and other pests.

Monitoring (Scouting)

Monitoring pests involves:
regular checking of the area;
early detection of pests;
proper identification of pests;
identification of the effects of biological control agents.

Regular checking of a warehouse, bakery, restaurant, field, greenhouse, golf course, or other areas and early detection of pests can function together like an early warning system for pests, helping to avoid or prevent a pest problem.
Proper identification of pests is an extremely important prerequisite to handling problems effectively. For example, the brown banded and German cockroach can be easily confused with each other. Identification is important because certain management practices may control only one species and not the other. Correct identification enables you to manage the real source of the problem and avoid merely treating the symptoms (or controlling non-pests). Some pests cause similar evidence. Unless the pest is identified, the control program may have the wrong pest as its target. Identification enables you to cure the pest problem and avoid injury to non-target organisms, particularly if you:

use a pesticide that is specific to the pest;

control the pest effectively during the most susceptible stage of its

life cycle;

consider the use of a non-chemical control.

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Identifying the effects of biological control means knowing which creatures are helpful and determining if pests have been affected by the beneficial organisms. Sometimes pests are kept in check naturally, and at other times the pest populations increase sharply.

Assessment

Assessment is the process of determining the potential for pest populations to reach an economic threshold or an intolerable level. Is a grower likely to suffer financially? Is the pest likely to transmit a disease? How can you tell? There are important differences between the assessment of crop pests and urban pests.

Forecasting can help you determine if weather conditions will be favorable for the development of diseases and insect pests. For example, by "plugging in" values (such as the number of rainy days and the temperatures for those days), growers can predict outbreaks and spray only when conditions are favorable for diseases. Growers who have kept good records of pests in previous years can use these records to help determine if problems such as weeds, insects, and diseases will reoccur. They might be able, for example, to apply the most effective herbicides at the proper time for early control of a problem.
Thresholds, or more specifically economic thresholds , are levels that mark the highest point a pest population can reach without risk of economic loss. Populations above these thresholds can reach the economic injury level, where they cause enough damage for the grower to lose money. At the economic injury level, the cost of control is equal to the loss of yield or quality that would result otherwise.

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Thresholds for many pests and crops have been scientifically determined. The advantage of thresholds is that if a pest has not reached threshold, there is no risk of economic loss. Therefore, there is no need to spray. Once the pest density (number of pests per unit area) has reached threshold, action is justified. The costs of control will be less than equal to the estimated losses that the pests would cause if left uncontrolled.

Urban pest thresholds are often related to aesthetics rather than economic considerations. Where health concerns or individual sensitivities exist, the tolerable level of the pest may be zero. A zero threshold forces action, even if only one pest has been detected. Zero thresholds exist in hospitals, food production, warehousing, and retail facilities.

Action (Control Measures)

Once a pest has reached the economic threshold, or intolerable level, action should be taken. In some situations, cultural controls can destroy pests. One example is early harvesting to avoid pest problems, which prevents crop loss and can sometimes be more economical than a pesticide application.

Chemical pesticides are used as a control measure when no other strategies will bring the pest population under the threshold. In fact, the success of waiting until a pest reaches threshold usually hinges on the availability of a pesticide that will bring the pest populations down quickly.

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In summary, an IPM approach means that pest managers use multiple tactics to prevent pest buildups, monitor pest populations, assess the damage, and make informed management decisions, keeping in mind that pesticides should be used judiciously.