The essential elements of IPM are monitoring of pests, assessment of pest numbers, use of multiple control measures (e.g. cultural controls, biological controls, and chemical controls), record keeping and evaluation, and communication and education.
1. Monitoring is a key element of IPM.
The results of a monitoring program provide important information to determine the need for control actions, as well as a way to assess whether control actions actually worked.
- 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. For example, checking around a structure in the spring for the nest building activities of wasps (i.e. yellow jackets) may prevent the need for using pesticides later in the summer as well as preventing a potential health problem. More recently, the use of pheromone (natural insect scents) traps has become a common IPM technique to detect the presence and activity periods of certain pests, such as various stored product pests and has even been used as a control measure in some agricultural crops.
Proper identification of pests is an important prerequisite to handling problems effectively. Identification is important because certain management practices may control one species but not the other. Ants and termites look similar as winged adults, but the methods of their management are very different.
Correct identification allows a pest manager to manage the real source of the problem and avoid merely treating the symptoms (or controlling non-pests). For example, the woods cockroach behaves and looks like indoor breeding roaches but is only an occasional intruder from the outside requiring little or no control.
Unless the pest is identified, the management program may have the wrong pest as its target. Identification allows a pest manager to determine the best course of action to solve a pest problem and avoid negative impacts 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; or
- consider the use of a non-chemical control.
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 naturally kept in check, and at other times the pest populations sharply increase.
2. Assessment is the process of determining the potential for pest populations to reach an action threshold or an intolerable level.
Is a grower likely to suffer financially? Is the pest likely to transmit a disease? There are important differences between the assessment of crop pests and urban pests. IPM treatment decisions are often based on certain thresholds.
The economic injury level is the number of pests which cause damage (loss of yield or quality) that is equal to the cost required to control the pest. A grower does not want a pest to cause damage, but he/she also does not want to spend money in treating the pest if it is not going to cause much damage. Spending $100 to treat a pest that is only going to cause $50 in damage is not good business. Therefore, treatment must be applied when it is anticipated that the economic injury level is going to be exceeded. The economic threshold is the highest point a pest population can reach without risk of its reaching the economic injury level. Economic injury levels are dependent on many factors, including value of the crop, stage of the crop, the amount of damage the pest makes, and the cost of a specific treatment. These factors have been calculated and estimated for a number of pests on several crops. However, when precise information is not available for all the factors required for calculation of an economic threshold, the highest tolerable pest level is often calculated and presented as the pest action threshold.
It is often virtually impossible to determine the “value” of some crop or settings. How much is a putting green on a golf course worth? How much is a cockroach-free school cafeteria worth? Urban pest thresholds are often related to aesthetics or health concerns rather than economic considerations. Where health concerns or individual sensitivities exist, the tolerable level for a certain 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.
The advantage in using thresholds is that if a pest has not reached the threshold level, there is no risk of economic loss and, therefore, there is no need to spray. Once pest numbers have reached the threshold level, action is justified. The costs of control will be less than the estimated losses that the pests would cause if left uncontrolled.
Forecasting, an assessment process, can help you determine if weather conditions will be favorable for the development of diseases and insect pests. For example, by using environmental information, such as periods when leaves remain wet (wetting periods), apple growers can predict when apple scab development occurs and spray only when conditions are favorable for the disease.
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 are likely to reoccur. For example, they might be able to apply the most effective herbicides at the proper time for early control of a problem.
3. Action (Control Methods)
Once the number of pests reaches an action threshold, steps (actions) need to be taken to control or minimize the impact of the pest. Below are several tools that can be use as control measures.
a. Cultural Controls
Cultural Controls are those methods that change the environment of the pest, making it less favorable. In an agricultural setting, plowing, crop rotation, removal of infected plant material, sanitation of greenhouse equipment, removal of pest harborages, and effective manure management are all cultural practices that are employed to deprive pests of a comfortable habitat. In an indoor setting, clutter reduction and proper cleaning practices are cultural practices that discourage pest survival. Outdoor practices such as proper planting and pruning techniques and selecting insect or disease resistant varieties are also effective cultural techniques.
Pest-resistant plant varieties are less susceptible than other varieties to certain insects and diseases. Use of such resistant varieties often means that growers or pest management professionals do not need to apply as many pesticides as they would with susceptible varieties. Apple growers can save up to eight fungicide applications a year by growing scab-resistant apples such Liberty and Freedom cultivars. Farmers growing alfalfa and wheat also keep several pests at bay by planting resistant varieties. Plant breeders have developed many flower crops that are resistant to one or more insect pests. Turf managers can suppress common surface feeding insect pests by using endophytic grass and seed mixtures. Arborists can recommend new birch varieties within the landscape that are tolerant of borers.
Management of urban pests is improved when sanitation programs are implemented, pest harborages are eliminated, and garbage pickup frequency is increased. Flying insect pests can be reduced when lights, that do not attract insects, such as high-pressure sodium-vapor lamps, are installed. Removing tree stumps and lumber scraps (which are prime food sources for subterranean termites) from construction sites, can prevent problems with these pests.
Cultural controls also include practices which are sometimes classified as physical controls or mechanical controls. These include structural modifications and barriers which prevent pests from entering a building or infesting a crop. 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. Improving water drainage is also an important cultural control measure for urban pests.
Physical barriers such as netting over small fruits and screening in greenhouses can prevent pest problems. Vegetable crops may be covered with spun-bonded polyester to prevent moths and flies from laying their eggs in crops. Physical barriers are extremely important in termite, housefly, and rodent management. Screens, metal shielding, and door sweeps should be maintained to prevent pest infestation. Other physical controls include light traps, sticky traps, multiple-catch and snap mousetraps, heat and cold treatments, electrical current, and simple physical removal of the pest via handpicking or vacuuming.
Cultural controls are often simple and inexpensive but they usually must be applied in advance of a pest problem in order to be effective. Advanced planning is important. Therefore, once an IPM plan is implemented, these preventive measures can be used annually and/or seasonally to reduce the buildup of pests.
b. Biological Control
Biological Control is the use of natural enemies (biological control agents) to help manage pests. Biological control agents include predators (e.g. ladybird beetles and other beetles, fly larvae, adult wasps, ants), parasites (e.g. nematodes and specialized flies and wasps) and diseases (especially bacteria, fungi and viruses). There are three types of biological control: introduction, augmentation and conservation.
Introduction refers to the release of natural enemies of pests into new areas or regions. Introduction of natural enemies is carried out under government regulations to insure that these introduced natural enemies do not themselves become pests. Many of our pests originally came from different continents. These include the multi-colored Asian ladybird beetle, spongy moth (Lymantria dispar), the imported cabbageworm, the Japanese beetle, and the European corn borer, among others. When these pests were imported, their natural enemies were left behind. By collecting natural enemies from the region where the pest originated, and then introducing these natural enemies in the “new” location, pest populations can be reduced and stabilized. An introduced parasitic fly and a fungus have successfully reduced spongy moth populations in community settings. Numbers of alfalfa weevil, previously a significant pest in alfalfa, have dropped following the introduction of a parasitic wasp. Studies are currently being conducted on the use of parasitic wasps to control the lily leaf beetle, a serious pest in landscapes.
Augmentation is the addition of (usually native) natural enemies directly into a system to reduce pest numbers. Many biological control agents are commercially available for augmentation. Predatory mites are released into orchards and strawberry fields to reduce spider mite numbers. Parasitic nematodes are applied to cranberry bogs to control root weevils. Ladybird beetles are commonly released in greenhouses to control aphids. Augmentation includes both inoculative releases, in which small numbers of beneficial insects are released over a period of time, which reproduce to become effective against pests, and inundative releases in which high numbers of beneficial insects are released.
The most important biological control method in agriculture is conservation. This is a selection of methods which preserve and encourage natural enemies that are already present. In agriculture, conservation methods include providing refuges for natural enemies, planting food crops, pruning and spraying in alternate rows, planting cover crops, managing water use, and applying pesticides selectively. Conservation is being recognized and practiced increasingly in a variety of settings, such as mosquito control. For example, open marsh water management (OMWM) has been successful in Massachusetts by allowing predators, such as fish, to feed upon salt marsh mosquitoes. To conserve natural enemies, pesticides with low toxicity to natural enemies must be selected and they should be applied in a manner to reduce natural enemy exposure. Leaving a low population of pests in the field also encourages natural enemies; since, when their prey is eliminated, natural enemies do not remain in the area for long.
It is important to remember that biological control is part of a biological system. In order for it to work effectively, a stable environment must be provided. Disturbances to the system such as wide temperature and moisture fluctuations or pesticide applications may reduce the probability for successful biological control. Biological control also takes time, so the practitioner must plan releases in advance. Also, because biological control is a dynamic system, it does not completely eliminate pests, but can reduce them to low levels.
c. Chemical Control
Chemical Control - Pesticides are important and commonly used tools in IPM. However, they must be used in an appropriate and timely manner to help the IPM system to function. This requires first determining whether a pesticide is needed and then selecting one that best fits the management program.
In recent years, there has been a movement to register active ingredients that are considered reduced risk pesticides. These reduced risk pesticides include biological pesticides. Biological pesticides include microbial pesticides (microorganisms such as fungi and bacteria formulated as pesticides) and biochemical pesticides which include pheromones (natural insect scents), insect and plant growth regulators (to affect the growth and molting process), and hormones. Other reduced risk pesticides include petroleum oils (to suffocate insects, mites and their eggs), repellents (widely used in vertebrate management) and soaps (specifically formulated and tested as insecticides and herbicides). A new category of pesticides, that has yet to be widely used, is called minimum risk pesticides. Active ingredients that are included in this category are corn oil, mint oil, garlic, peppermint, and white pepper. When considering which pesticides to use, it is important to note that the efficacy of some of these “new” pesticides are unknown.
Certain pesticides can provide immediate results in reducing pest populations. However, because of their toxicity and potential environmental impact, and because they are disruptive to the biological system, they should be used as a control measure when no other strategies will bring the pest population under the threshold.
Like all control actions, pesticides should be selected that are effective in controlling the pest, least disruptive to natural enemies, least hazardous to human health and least damaging to the general environment. These pesticides are likely to have a narrow host range, have low mammalian toxicity, and breakdown quickly in the environment. Additionally, pesticides of a similar mode of action should not be applied repeatedly, so as to prevent pests from developing pesticide resistance.
4. Record keeping
Record keeping involves the systematic storing and retrieval of IPM information. While federal and/or state law requires pesticide application records, in most situations the collection and use of other information can improve decision-making and provide more effective control. For example, the results from a monitoring program will indicate what a pest population looks like at various points in time. More extensive records can provide indications of increasing or decreasing numbers of pests or natural enemies, which could influence a decision about the treatment. In agriculture, weather records, coupled with pesticide application and pest sampling records, could indicate how well a specific pesticide performed in a certain situation. This evaluation could be useful in future seasons. A similar evaluation for a facility or athletic field can be made by tracking pesticide use patterns and other control strategies that may indicate that additional tactics are necessary.
5. Communication and Education
Communication and Education involve having informed individuals available to report pest problems or conditions conducive to these problems. Examples include scouts in a cranberry bog and food service workers in a cafeteria. In addition, these individuals can educate and train others to understand the essential elements of IPM in order to involve them in the IPM program. Invariably, communication and education can play a role in the overall success of any IPM program.
An Overview
All of the components of an IPM approach can be grouped into four major steps.
Taking preventive measures (cultural practices, communication, and education) to avoid pest buildup.
Once an integrated pest management approach is adopted, preventive measures can be taken that will reduce or slow the development of pest populations. For agricultural settings, these preventive measures include cultural controls such as crop rotation, pest resistant plant varieties, alternating planting dates, pruning, and sanitation. In a non-agricultural setting, preventive measures include adopting facility designs that will deter the development of pest populations. For example, positioning equipment off the floor in a commercial kitchen can insure easier and more thorough cleaning, using better construction methods can deter termite attack and infestation, and convincing consumers to use insect-proof containers for food or window screens in their homes, can be considered to be preventive measures. Communication and education are important since your customer and/or client can be an integral part of success of these preventive measures.
- Monitoring occurs throughout the season or year. This is done by looking or sampling regularly for the appearance of insects, weeds, diseases, rodents, and other pests. Regular sampling, in both agricultural and non-agricultural settings, means using devices, such as sticky and/or pheromone traps, to detect pests.
- Assessing the pest situation
Assessment also occurs throughout the season or year. An action threshold has to be determined for each pest that is identified through the monitoring process.
- Determining the best course of action. If a pest reaches the action threshold, a control measure should be implemented. Accurate records will help to determine which control measures are appropriate. In IPM, control measures should be selected that are:
- least disruptive to natural enemies
- least hazardous to human health
- least damaging to the general environment
- most likely to result in permanent reduction of pests
- most cost-effective in the short- and long-term
In many IPM programs, cultural control strategies are employed first, biological control options are used next, and pesticides are used only as a last resort.
In summary, an IPM approach means that pest management professionals and growers use multiple tactics to prevent pest buildups, including monitoring pest populations, assessing the damage, making informed management decisions, and keeping in mind that pesticides should be used judiciously, after other alternatives have been tried. Ultimately, the IPM strategy serves agriculture, the environment, and human health as the most logical means to manage pests effectively, while using the least amount of chemical necessary.
Glossary
- Biochemical pesticides: Pesticides that are naturally occurring substances that control pests by usually non-toxic mechanisms. Biochemical pesticides include substances, such as pheromones, hormones, natural plant regulators, natural insect growth regulators, and enzymes.
- Biological pesticides: Pesticides that include naturally occurring and genetically engineered microorganisms (microbial pesticides), genetically engineered plants that produce their own pesticides (plant-pesticides), and naturally occurring compounds that are not toxic to the target pest (biochemical pesticides).
- Biological Control: Pest control without the use of chemicals. Parasites, predators, diseases, etc., are used to control pests
- Chemical Pesticide: Term used to describe a pesticide which is a chemical rather than a parasite, virus or some other type of pest killer.
- Economic threshold: The point of pest infestation where application of a control measure would return more money that the cost of the control procedure.
- Harborage: An area or site that pests find suitable to live such as cluttered and/or unclean places
- Insect growth regulators: Pesticides that disrupt the molting, maturing from pupal stage to adult, or other life processes of insects.
- Juvenile hormones: Natural insect chemicals that keep the earlier stages of an insect from changing into the normal adult form.
- Microbial pesticides: Pesticides that contain microorganisms, such as bacteria, fungi, viruses, and protozoa, as the active ingredient. These pesticides can be applied like chemical pesticides in the form of dusts and spray mixtures.
- Minimum risk pesticides: Chemical pesticides classified by the EPA as exempt materials under 40 CFR 152.25. The active ingredients covered by this exemption include, cedar oil, citronella, corn gluten meal, dried blood, garlic, mint oil, thyme and white pepper. Most of these active ingredients come from plants. Others come from animals (dried blood and putrescent whole egg solids), metals (zinc metal strips) or chemical compounds like sodium chloride (common salt).
- Monitoring: Regular checking and identification of pests and effects of biological control.
- Multiple catch trap: A mechanical device that attracts certain kinds of pests, such as mice, that can automatically reset and can catch many pests.
- Natural Enemies: The predators and parasites which exist in the environment and attack pest species.
- Nematode: A tiny, hair-like worm that causes damage by feeding on roots or other plant parts.
- Parasite: A plant or animal that harms another living plant or animal (called the host) by living or feeding on or in it. Sometimes parasites are helpful to man by attacking and controlling pests which could injure crops or animals. These parasites are forms of biological control.
- Pesticide Resistance: Genetic abilities developed by pest populations that enable them to resist the effects of certain types of pesticides that are toxic to other members of that species.
- Predator: An organism that attacks, kills and feeds on other animals or insects.
- Pheromones: Chemicals emitted by an organism to influence the behaviors of other organisms of the same species.
- Pheromone traps: A device that contains a pheromone that is used to attract, trap, or kill a target pest.
- Plant growth regulators: Substances (excluding fertilizers or other plant nutrients) that alter the expected growth, flowering, or reproduction rate of plants.
- Reduced risk pesticides: Pesticides that contain active ingredients that pose reduce risk to human health, reduce risk to non-target organisms, reduce potential for contamination of the environment, and/or broadens adoption of IPM or makes it more effective.
- Refuge: A place where beneficial insects are sheltered.
- Repellent: A pesticide that keeps or drives insects or other pests away from the plant, animal, or surface treated.
- Sticky traps: A non-chemical device that has a sticky surface which catches pests. It is used as a monitoring tool to confirm the presence and identity of pests.
Additional References
If you are interested in obtaining more information about IPM for specific sites and/or crops, check out the UMass Extension IPM program.