Integrated Pest Management (IPM): Definition, Philosophy and Control Options

In this article we will discuss about Integrated Pest Management (IPM):- 1. Definition of IPM 2. Why Practice IPM? 3. Basic Steps 4. Philosophy 5. Control Options.

Definition of IPM:

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 to combine. It is a combination of many strategies that 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.

Why Practice IPM?

It is a pertinent question to ask, why should one consider IPM when chemical pesticides so often succeed at controlling pests? There are some reasons for having a broader approach to pest manage­ment than just the use of chemicals.

These are given below:

(a) To Keep a Balanced Ecosystem:

Every ecosystem is made up of living things and their non-living environment. The living and non­living constituents of the ecosystem maintain a highly tuned balance in nature. The actions of one creature in the ecosystem usually affect other orga­nisms of same or different species.

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.

(b) Pesticides can be Ineffective if not Used in IPM Method:

Chemical pesticides are not always effective. Pests can become resistant to pesticides. In fact, some 600 cases of pests, developing pesticide resistance varieties have been documented to date, including common lamb’s-quarter, houseflies, 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 it and is washed off. It may be applied at an improper rate, or is applied at an improper life stage of the pest.

(c) IPM is not Difficult:

If one have figured out the problem (the pest), determined the extent of the damage and decided on the action to take, he has already done most of the important steps in IPM. These steps are the ones used in 1PM. Therefore, it is very easy to practise.

(d) IPM Saves Money:

IPM can save money through avoiding crop loss (due to pests), and avoiding unnecessary pesticide expenses. For example, onion growers who followed IPM recommendations in 1987 saved more than Rs 1000.00 per acre in insecticide costs.

Golf course superintendents who replace fungicides with organic fertilizers or composts can save up to Rs 60000.00 every time. Applicators are able to save on sprays because the calendar is not the basis for spraying; the need is the basis.

(e) To Promote a Healthy Environment:

Nowadays a severe problem to mankind is arising with the persistent presence of different chemicals in the environment along with their effect on living creatures. Reports of several cases of contaminated groundwater appear each year.

Disposal of containers and unused pesticides 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.

(f) To Maintain a Good Public Image:

Recent public outcry about the presence of pesti­cide residues on produce and the use of growth regulators has heightened pesticide applicator awareness of the level of public concern about che­micals. Consumers are pressurizing food stores, which in turn are pressurizing producers for products that has been grown with as few pesticides as pos­sible.

Growing food under 1PM can help allay public concerns. Structural pest control professionals can suggest improvements in housekeeping or structural modifications as substitutes for chemical control.

The Basic Steps of IPM:

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.

All of the components of an IPM approach can be grouped into four major steps:

1. The first step is taking preventative measures to prevent pest build-up.

2. The second is monitoring.

3. The third step is assessing the pest situation.

4. The fourth is determining the best action to take.

These steps are thoroughly discussed below:

1. First Step of IPM: Preventative Measures:

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

Cultural controls are those that disrupt the environment of the pest. Ploughing, 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.

Structural modifications such as by preventing support timbers from soil contact, damages 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 of tree stumps and lumber scraps from construction sites, which are prime food sources for subterranean termites, can prevent problems in the future. Biological controls by 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 other 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, housefly, 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 of cultivable plants are those, which 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 is 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.

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.

2. Second Step of IPM: Monitoring (Scouting):

Monitoring Pests Involves:

(a) Regular checking of the infested area.

(b) Early detection of pests.

(c) Proper identification of pests.

(d) 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 for handling problems effectively. For example, the brown banded cock­roach 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 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 programme may have the wrong pest as its target.

Identification enables to cure the pest problem and avoid injury to non-target organisms, particularly if:

(a) Use a pesticide that is specific to the pest.

(b) Control the pest effectively during the most susceptible stage of its life cycle.

(c) Consider the use of a non-chemical control.

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

3. Third Step of IPM: Assessment:

Assessment is the process of determining the potential for pest populations to reach an economic threshold or an intolerable level. There are impor­tant differences between the assessment of crop and urban pests.

Forecasting can help to determine weather condi­tions will be favourable 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 favourable 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 re-occur. 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 (see Fig. 1.21).

Thresholds for many crops and pests 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 apply any control measure.

Once the pest density (number of pests per unit area) has reached threshold, action should be taken. The costs of control must be less than or at least equal to the estimated losses that the pests would cause if left uncontrolled.

Zero Thresholds:

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.

4. Fourth Step of IPM: 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.

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.

Philosophy of Integrated Pest Management (IPM):

Integrated Pest Management or 1PM provides a systematic approach to pest control. It begins with using the best cultivation practices. Following the correct selection and culture of plants, reduces the potential for pests and diseases.

When problems arise, the essential step in an IPM program is determining when a pest is causing enough damage to warrant control. It also helps the cultivator to determine which of the many possible control measures is most effective and appropriate in a particular situation. IPM can be applied to all floral and faunal pest groups.

Correct Cultural Practices:

Cultural practices should be designed such that the cultivator has ways and means of implementing correct practices as per changing environmental factors that affect the plants and their pest popu­lations. Cultural practices include irrigation, crop rotation, garden sanitation, soil aeration, mulching, tilling and use of disease- and pest-resistant plants. It is essential that the cultivators should know critically the cultural or growing requirements of each plant.

Providing the correct growing conditions result in a vigorous plant that is less likely to be attacked by pests and diseases. Vigorous plants also can tolerate tissue damages.

The question of when an organism becomes a pest is central to IPM. Deciding how much damage is acceptable with a particular plant or crop is called “establishing a threshold”.

Establishment of Threshold:

Several factors influence how each cultivator will arrive at a pest threshold.

These factors include the following:

1. Amount of damage that can be tolerated.

2. Pest population size required to cause signi­ficant damage.

3. The plants’ stage of development.

4. The vigour of the threatened plant(s).

5. The life cycle and habits of the pest.

The amount of damage that can be tolerated varies with the crop and personal preferences. A few holes on a collard leaf do not require control. However, if most of the leaf has been eaten, the crop is destro­yed.

Less than 12 white grubs in a square foot of turf grass can be tolerated as long as the lawn is growing vigorously. However, if the density of grubs rises above 12 per square foot, damage will be significant.

Colorado potato beetles devastate a potato crop early in the season. However, in the latter part of the season, they feed on the foliage and practically no damage is done to the crop.

Peach tree borers are extremely difficult to control once they bore into the trunk of the tree. Knowing that the adults lay eggs in mid-July to mid-August and that the young larvae are susceptible during this period, the cultivators are advised to effectively apply control measures.

Establishing thresholds in the field involves observing the plant and its total environment.

There is also the question: Does the cure process cause more damage than the pest? There is a risk involved in using the more toxic pesticides. This risk must be weighed against the potential benefit.

Inspection and Monitoring:

One must monitor the field to determine when action is necessary. Thorough inspection of the plant includes – the underside part of leaves, buds, new growth and even the roots in extreme cases. Regular inspection allows the cultivator to identify a problem before major damage occurs to the plant.

Controls will be more effective if the problem is caught early. Infrequent inspection results in extensive damage. Once extensive damage occurs, it is often too late to do anything.

Inspection of the plant’s entire environment for clues to the problem is a good practice for a good cultivator. Too much or too little moisture, wind, humidity and light may cause stress that results in susceptibility to damage from pests and diseases. Observing and keeping records of weather conditions provide clues to growth patterns and problems.

Certain insect pests can be monitored by using traps. Coloured, sticky traps, pheromone traps, pitfall traps and light traps are used with some pests. White- flies and aphids are attracted to bright yellow, sticky cards and are trapped on the sticky surface.

Identifying the Cause of the Problem:

The problem may be caused by insects or related pests, diseases or cultural practices. Often, the problem is caused by a combination of these factors. Identification of the pest or disease and the condi­tions that allow organism to become a problem is of prime importance. Reference materials are guide to common problems for a particular plant.

They list the insects and diseases that attack each plant. The ORTHO PROBLEM SOLVER is an excellent resource for identification. A questioning attitude and close inspection are required to make an accurate diagnosis.

A magnifying or hand lens is help­ful. Close examination of the specimen for feeding or disease patterns is essential. If insects are involved, collection of the pest is essential. Identification of insects and diseases is available through local Exten­sion offices and the Plant and Pest Identification Organizations.

Application of Control Measures:

To apply a control measure, one must understand the pest organism, its life cycle and the type of damage it causes. All control options should be considered. The most effective and appropriate option or combination of options should be selected. Control measures should be taken as fast as possible and at the right time.

Insects are more vulnerable at certain stages of their life cycle. Eggs may be con­trolled with oil sprays. Larval stages are particularly vulnerable. It is critical to control insects before they reproduce and increase their population. When an insect is protected by the pupal case, control is nearly impossible.

Re-application of control measure may be neces­sary for many pests to kill the young as they emerge from eggs. It is important to know, how long the pesticide remains effective on the plant. This is also important in food crops. Cultivator must observe the prescribed time lapse between the last application and harvest.

Diseases are more difficult to control. Most of the fungicides prevent infection or at best stops an infection from spreading. Netting is not effective if there are unprotected areas. Pesticides must be applied to both the top and underside of leaves.

Surfactants or spreader/stickers help the pesticide adhere to and spread over the foliage surface. Appli­cation rates are critical. The proper dilution is required to kill the pest. If it is too concentrated, plant damage may occur. Application of control measures should be as instructed by the authentic organization.

Control Options for IPM:

Control options can be arranged by their mode of action and their impact on the environment.

Generally, these are grouped from least to highest impact:

(1) Cultural and mechanical controls,

(2) Biological controls and

(3) Chemical controls (soaps and oils, botanical pesticides and synthetic pesticides).

1. Cultural and Mechanical Controls:

Keeping plants healthy and growing vigorously should be the first line of defense against pests. The next level of control includes hand removal, use of screens, barriers, traps, freezing and crushing. These are excellent options for the home cultivator. Mechanical methods generally have little or no negative effects on the environment.

(a) Hand Removal:

This method is suitable for larger insects. Shake pests into a can that contains a small amount of water and detergent. Scrape off and crush egg masses.

(b) Screens and Barriers:

Any material that is fine enough to keep pests out can be used as a barrier. Screens can keep out large insects, birds and rabbits. Floating row covers well anchored to the ground can prevent attack by nearly all insects. These will also prevent pollination by insects, resulting in lack of fruit.

Cardboard and metal collars will prevent cutworms from reaching young transplants. Sticky bands placed on tree trunks to trap cankerworm and elm leaf beetles. Diatomaceous earth is advertised as a barrier to keep slugs from damaging plants.

The sharp particles, or diatoms, are supposed to cut the slugs’ underbody. However, recent reports indicate that it is not effective. The small particle size quickly becomes incorporated into the soil, especially after a rain or irrigation. Copper strips also are offered as a control. They supposedly react with the slugs’ slime to shock them.

(c) Trapping:

Traps usually serve as a monitor­ing system, warning of the presence or increase in undesirable pest numbers. Traps also can be useful in timing control measures. They are sometimes used to control numbers. Yellow, sticky traps attract white- flies, aphids, thrips, leafhoppers and other small flying insects.

Traps that use pheromones or attrac­tive scents to tantalize adult insects are best used as a way to check presence and numbers. Pheromones are used in Japanese beetles traps.

Pitfall traps are cups or jars placed into the ground. Weevils, cutworms and other pests fall into the traps. Light traps capture insects using a black light (ultraviolet). These are used by advanced cultivators to monitor night-flying pests. “Bug zappers” are not considered useful because they kill beneficial as well as pests.

(d) Syringing:

A hard stream of water from a hose, washes aphids, spider, mites and other small insects from plant foliage. This must be done frequently since it does not kill insects or eggs. It does not prevent some insects from crawling back onto plants.

2. Biological Controls:

Nearly every species of plant-feeding insect has another insect that is its predator or parasite. Biological methods of control utilize natural enemies of pest insects to keep their populations under control. Biological controls involve several options: predators and parasites, microbes, etc.

(a) Predators and Parasites:

Predatory and parasitoidal insects and mites are often termed “beneficials”. Beneficials include predators such as lady beetles, lacewings. syrphid flies, wasps and praying mantises as well as parasitoids, including certain wasps, flies and mites.

There are some parasitoids associated with the larvae of Leucinodes orbonalis (Brinjal pest), they are — Pristomerus testaceus, Cremastus flavoorbitalis, Bracon sp., Shirakia schoenobii and Iphiaulax sp.

Cultivator should learn to recognize beneficial insects. The use of NON SELECTIVE insecticides kills these helpful insects. Rather than trying to introduce beneficial insects into the landscape, avoiding the killing of those that are already there, is a good prescription. A small pest population must continue or the “beneficial” will die from lack of food. Purchasing “beneficial” is only recommended for use in greenhouses.

Parasitic insects are less well known than preda­tors, but equally effective. They lay their eggs in a pest species. When the eggs hatch, the larvae feed on the pest insect, killing it. Most of the parasitic insects are tiny wasps.

Many birds and bats eat insect pests. It is advisa­ble to provide water and shelter so as to encourage them to visit your garden.

(b) Microbes:

Bacteria, fungi, viruses, protozoans and parasitic nematodes are microorganisms that attack insects. These microbial “insecticides” are generally effective against very specific pests. As they pose little risk to humans and the environment, microbials are likely to be used more in the future with better pre­ventive measures.

Many cultivators are familiar with a popularly known, microbial-based insecticide called as “Bt” or Bacillus thuringiensis, bacteria which produces a toxin that kills specific caterpillars. The larval pest usually dies within 4 to 7 days. It is a commercially available product (Dipel™, Thuricide™) used to control many kinds of moth and butterfly larvae. There are many STRAINS of “Bt”, each type controlling specific pests.

Parasitic nematodes are very effective against certain pests that live in the soil. However, the nematodes require moist conditions to survive. Few fungi, viruses and protozoa are commercially available, however, these living organisms are diffi­cult to raise, store and apply.

3. Chemical Controls:

Controlling pest by chemical substances is called chemical control and the chemical is called ‘pesti­cide’. Pesticides are any substances used to kill a pest. “Cide” means to kill; therefore, an insecticide kills insects and an herbicide kills plants. We also have miticides, rodenticides, molluscides, fungicides, etc. Pesticides include repellents, attractants, growth regulators, defoliants, anti-desiccants and antibio­tics.