Towards an integrated product... - Section 4-Principles and theory of integrated pest management (2023)

Section 4 - Principles and Theory of Integrated Pest Management

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The concept and components of integrated plant protection
Some Basic Economic Principles in Pest Control
Socio-economic and technical dimensions of integrated pest management

The concept and components of integrated plant protection

Belen Morallo-Rejesus
Professor and President of the Department of Entomology
College of Agriculture, University
from the Philippines in Los Banos

e

Romeo S. Rejesus
Advisor, Post-Harvest Research
and Training Center, Department of Horticulture
Visiting Professor, Department of Entomology, University of the Philippines at Los Banos

INTRODUCTION

The goal of development is to maximize the use of energy, natural resources, capital and scientific information for the benefit of mankind. However, the process of development of agricultural production, management of water resources, improvement of health and other human activities creates a favorable environment for the development of organisms that compete with humans. be harmful and edible at the same time. For example, crickets and grasshoppers are acceptable food for some people but can be a bane for rice farmers.

A pest problem is when an organism interferes with human activities or desires, or otherwise competes with humans. To minimize or rationally control pest infestations, a holistic approach to suppression is emphasized. The control strategy developed later is called Integrated Pest Management (IPM).

INTEGRATED PEST MANAGEMENT PHILOSOPHY

IPM brings together in a workable combination the best strategies of all control methods applicable to a specific problem caused by pest activity. IPM has been defined in many ways, but a more scientific definition describes it as "the practical manipulation of pest populations, using sound ecological principles, to keep pest populations below levels that cause economic damage". The emphasis here is on “practical” and “ecological”. There are many ways to control insect pests, but few are practical and less environmentally friendly, creating an unwanted quote.

Another term we often come across is "integrated pest management". It is used interchangeably with IPM, although strictly speaking these terms are not the same. Originally, integrated control simply meant modifying chemical control to protect beneficial insects and mites, or integrating chemical and biological control methods. The concept was later expanded to include any suitable methods that could be used in a complementary manner to reduce pest populations and maintain them at levels that do not cause economic damage. This is essentially MIP. It includes a variety of options, each of which may not significantly reduce the pest population, but the total of which will result in a reasonable reduction to avoid economic loss. A modern definition of IPM might be the use of all tactics available in designing a program to manage, but not eradicate, the pest population in a manner that minimizes economic damage and adverse environmental side effects.

IPM is not a static and inflexible system. It is dynamic and constantly changing as we gain a better understanding of all the factors affecting the system. These factors include climate, alternative host plants, beneficial insects, and human activities. but also secondary pests that rarely cause damage. If this were not so, we might suddenly find that some of these minor or even non-noxious insect pests are elevated to the status of serious insect pests because we don't include them in the overall scheme.

The concept of Integrated Pest Management is not new, but it is taking on new meaning as people look for better ways to grow and store food for a growing population while preserving their environment. There are three reasons to use IPM. First, it can reduce production costs mainly by reducing energy use. Second, IPM can reduce pollution through judicious use or reduced use of pesticides. Finally, an IPM program allows for maximum utilization of cultural practices and natural enemies (for crop pests) and physical methods (for storage pests). IPM can be designed to exploit the ecological principles that drive the abundance of pest populations. This requires a thorough understanding of the role of all factors responsible for a pest population reaching specific levels at a specific time of year or storage period.

IPM-ELEMENT

There are four basic elements of Integrated Pest Management: natural control, economic sampling, and insect biology and ecology.

The first element of the IPM relates to the fullest utilization of naturally occurring suppressive factors, including all human practices, that render the entire ecosystem less favorable to insect pest population growth. Obviously, this requires a thorough understanding of the ecosystem.

Naturally occurring suppressive factors can act directly or indirectly on pest populations. Indirectly, the ecosystem can be managed or modified in a way that makes the environment more harmful to the pest, thus limiting population growth. More directly, the protection and use of beneficial insects can help maintain populations of potentially harmful insect pests at subeconomic levels.

The second element is the use of sound economic thresholds (ETL) as a basis for the application of control measures, particularly chemical measures. Establishing and using dynamic ETLs provides a basis for delaying the use of insecticides. This allows for maximum use of other control methods, such as B. the use of beneficial insects.

The use of economic thresholds implies adequate sampling of all harmful and beneficial insects in the agroecosystem, and in particular all crops, at a given point in time. The sampled values ​​should then be compared to the established economic levels for the crop, the beneficial insects and the likely population trends of the pest species. The sampler thus becomes a key person in an IPM system.

The fourth element, insect biology and ecology, is essential to getting the most out of the other three elements. Without detailed knowledge of the biology and ecology of all species that occur, little can be understood about natural control. This knowledge is also essential to determine the role of each species in the system and to determine the extent of damage caused by each pest species. Proper sampling depends directly on a thorough knowledge of the species involved.

Knowledge of the biology of a particular problem pest informs the design of control strategies and provides practical guidelines for those strategies. In this context, it is important to know the relationship between pests and plants (Plant Hour Charts) and mortality factors (Pest Hour Charts), both biotic and abiotic (parasites, predators, temperature, relative humidity), which play an important role Determination of the population dynamics of pests.

An understanding of the sequential dominance of pests in terms of growth stages could provide immediate impetus for the development of a simple integrated control program based on minimal pesticide application (Rejesus, 1976). By delineating the sequence of key pests at different stages of crop growth (or storage time for stored produce), the frequency, timing and dosage of insecticide application can be synchronized, thereby avoiding time-based or "calendar" pesticide use. Method. The control program can then be based on the expected pest population at each growth stage for the duration of storage.

ECONOMIC DAMAGE LIMITS AND ECONOMIC LIMIT

There are large differences in the tolerability of pests, even for the same species in different areas, at different times of the year, on different host plants, and at different stages of plant development. Therefore, determining the level of economic damage is critical to defining the ultimate goal of any pest control program and delineating the pest population level below which damage is tolerable and above which specific intervention is required to prevent a pest explosion and significantly avoid damage (Fig. 1) . star and others. (1959) defined the economic damage level as “the lowest pest population that will cause economic damage”, while the economic threshold level (ETL) or more precisely Action Threshlod Control (CAT) as “the density at which control measures must be applied in order to prevent an increase in pest population from reaching the level of economic damage". While damage or loss can be tolerated or neglected at the economic threshold, every effort should be made at this level to control the pest population by various methods (ie chemical, physical, biological etc.).

Determining the level of economic damage and the limits of control measures is often a complex matter based on detailed pest ecology operations related to bioclimatology, predatory diseases, the effect of host plant resistance and the environmental consequences of interventions. Luckman and Metcalf, 1975). Rabb (1972) suggested the following factors as essential in determining the extent of economic damage:

1. Extent of physical damage associated with different pest densities.
2. Monetary value and cost of production of crops in various physical damages.
3. Monetary loss associated with varying degrees of physical damage.
4. Extent of property damage that can be prevented by the control measure.
5. Monetary value of the crop fraction that can be saved by the control measure.

Using this information, it is possible to determine the level of pest density at which control measures can be applied to save the crop equal to or greater than the cost of control.

The rise and fall of the control action limit is determined by ecosystem importance, crop value, pest status, and consumption patterns. For example, Heliothiscea, which feeds on cotton bolls, has an economic limit of four larvae per plant (Stern, 1965) and generally requires insecticide treatment several times a year. H. zea, which feeds on candy corn, has an economic threshold near zero population in the United States because the consumer will reject candy corn with damage or a larva inside.

In special cases, where pests serve as carriers of plant, animal and human diseases, the economic threshold is zero. A single pest infestation can result in the death of a valuable tree, pet or human. A good example is Aedes aegypti, which transmits yellow fever.

In grain storage, ETL is influenced by consumer attitudes. Export regulations often mandate zero tolerance for live insects, whether harmful or beneficial.

IPM COMPONENTS

Five general types of single component control methods can be used in IPM programs in stored ecosystems. These are: chemical control, physical and mechanical methods, biological control, host plant resistance and regulatory control.

Chemical Control:

A variety of insecticides and acaricides have been and are continually being developed to control insect pests. However, these chemicals are only a tool and should be used in combination with other tactics in an IPM program. Total dependence on chemicals has resulted in a crisis situation (including pest resurgence, insect resistance, secondary pest outbreaks, environmental pollution and human health risks). However, the IPM does not advocate the complete elimination of pesticides. That would be impractical. IPM simply requires the use of pesticides only when necessary and at levels consistent with other strategies.

Physical and mechanical methods:

Physical and mechanical methods are direct or indirect (non-chemical) measures that completely eliminate pests or render the environment unsuitable for their entry, spread, survival and reproduction. Physico-mechanical control measures can include environmental manipulation (temperature, relative humidity, controlled atmosphere), mechanical barriers, light tapping, irradiation, thermal disinfestation, sanitation, etc. it can only be economical in certain situations. For field pests, these methods are quite inefficient, but in a storage ecosystem, many of the physical techniques are effective and have great potential for use in an IPM system.

Biological Control:

Biological control can be defined in a narrower sense as "manipulation of predators or pathogens to control the density of an insect population". This definition does not include naturally occurring control agents, only parasitoids, predators and pathogens intentionally manipulated by humans. More broadly, it includes “the manipulation of other biological facets of the pest's life system, such as

There are some caveats to the potential and successful use of natural enemies. Predators, parasites, and pathogens found under grain are considered contaminants by grain consumers and exporters. Thus, it becomes very difficult to maintain a pest population level that allows the establishment of biological control agents. The use of pheromones is one of the potentially useful biological agents that can be used in IPM to monitor and partially suppress the pest population not only in agricultural fields but also in reservoir ecosystems.

Host Plant Resistance:

Manipulation of the host's genetic makeup to make it resistant to pest infestation is referred to as host plant resistance. Over the years there has been a great deal of success in creating resistance to a variety of pests and many crops are now selected for this purpose.

This approach has not been widely attempted in stored product protection systems. Few studies have been made in this area. However, research (mainly on rice, corn, wheat) has provided evidence of the usefulness of cultivar resistance in grain storage. Unless research on cultivar resistance to storage pests is integrated with breeding crops resistant to field pests, the potential of this IPM storage tactic is limited.

Regulatory Control:

The basic principles of regulatory control include preventing the entry and establishment of alien plant and animal pests in a country or area, and eradicating, containing or suppressing already established pests in limited areas. Various control measures are implemented under various quarantine laws to exclude potential pests, prevent spread and complement eradication programs. Ports of entry are the first line of defense against the introduction of new pests. Pests that pass through the port of entry are either eradicated or contained in limited areas. The quarantine measure is only used against economically important insects, although it is sometimes necessary to contain economically unimportant insects in another country until their behavior in a new environment can be studied.

Trogoderma granarium is the most serious storage pest and every effort is made to prevent its spread in international trade. In many countries, imported shipments containing J. granarium are separated and immediately fumigated with methyl bromide (at a dosage of 80 9/m³ for 48 hours). Recently, Central American Prostephanus trunkates have become a pest of international quarantine concern.

Component integration:

Each of the many insect control methods has its place in the IPM. There are many situations where two or more can be used in an integrated program. However, not all methods are suitable for use in all situations.

In a warehouse ecosystem, hygiene and good warehouse management are essential. It forms the framework for further supplementary methods of infestation control. An IPM system would therefore complement warehouse hygiene and good maintenance with one or more combinations of the following practices:

1. best harvesting and threshing techniques
2. judicious use of residual insecticides
3. Use of fumigants (MeBr; PH3)
4. Use of ambient ventilation and cooled ventilation
5. atmospheric gas modification (hermetic; CO2; N2)
6. thermal disinfestation
7. radiation techniques
8. insect resistant packaging
9. Insect Growth Regulators: (IGRs: Methoprene, Hydroprene)
10. Biological control (parasites, predators and entomopathogens, pheromones)
11. Use resistant varieties if possible
12. Memory management (FIFO)
13. Proper cleaning of grains before storage.
14. Warehouse design (to exclude pests, mainly for rodent and bird pests)
15. Proper cleaning of grains before storage
16. Monitoring, evaluation and inspection of stored goods, storage structures and their immediate surroundings.

Summary table for controlling insect pests (adapted from Osmun, 1985)

Insect pest control for stored produce

There are a number of differences to IPM for stored produce versus field farming. There is a much broader range of tactics that can be used to control storage pests. In both situations, a systems approach is used to facilitate monitoring and implementation.

Comparison of IPM between field farming and stored product pests

Field production

1. Ecological state - more complex and dynamic.
2. Reorganization process - difficult to implement.
3. Economic threshold – applicable as appropriate.
4. Physical control – often impractical and expensive.
5. Mechanical control – often impractical and expensive.
6. Regulatory control - more complex and requires intensive logistical support.
7. Chemical control - significant impact on the ecosystem.
8. Biological control - field
9. Host-Plant Resistance - Relatively easier modification of the whole plant.

Saved · Product configuration

1. Relatively simple and manageable.
2. Easier and alone could provide complete control.
3. Generally not applicable, the food industry does not generally require infestation.
4. Most physical factors can be manipulated under storage conditions.
5. Made more practical by the built-in memory function.
6. Usually independent detection and implementation.
7. More reserved and limited in the spatial spread.
8. contamination problem.
9. Genetic manipulation to only complicate seed resistance.

In both situations, three additional elements need to be included in the development of IPM: 1) appropriate people, 2) a systems approach, and 3) proper assessment. In addition to the individual expertise of the team members, it is important that the people involved develop a good personal and professional relationship in order to pursue common goals.

REFERENCES

FLINT, M. L. and VAN DEN BOSCH R. 1981. Introduction to integrated pest control. Plenum Press, NY and London. 240 p.

GLASS, E.H. (ed.) 1975. Integrated Pest Management, Rationale, Potential Needs, and Implementation. So that American Society. Specification PubI.75-12.141 p.

METCALF, R.L. and W. LUCHKMAN (eds.). 1975. Introduction to Insect Pest Control. John Wiley & Sons, New York 587 pp.

STERN, V. 1973. Economic thresholds. Anular Rev. Entomol. 18:259-280.

WATSON, T.P., L. MOORE, G.W. PORCELAIN. 1975. Practical Management of Insect Pests. W.H. Freeman & Co. San Francisco. 196 p.

OSMUN, J.V. 1985. Insect Pest Management and Control. InBauer, FJ ed. Insect management for food storage and processing. American Association of Cereal Chemists, St. Paul, Minnesota. pp. 15-24.

Some Basic Economic Principles in Pest Control

Belen Morallo-Rejesus
e
Romeo S. Rejesus

INTRODUCTION

Entomologists and biologists define pests as those organisms that reach a certain biomass or population size sufficient to cause physiological damage to the crop and ultimately affect the quantity and quality of the product. Concern was only focused on outlining control strategies with the aim of increasing the efficiency of pest control and/or minimizing the undesirable side effects of control on the environment. It involves simultaneously determining a damage function (one that relates yield losses or crop damage at the highest density levels) and an elimination function (one that measures the efficiency of a particular control strategy in terms of percentage of dead pests). Perhaps the ultimate goal of this effort is to maximize the yield potential of crops while eliminating the threats of pests, which is only possible when maximum protection is assured. In the past, maximum protection was closely linked to prophylactic pesticide dosages.

Economists see pest problems and solutions very differently. On the one hand, pests are those organisms that destroy what humans have produced, compete for the resources humans need to produce food and fiber, or pollute the environment in a way that humans find unhealthy or unattractive (Headley and Lewis, 1967). An economist would not be very specific about the exact levels of pests, damage, and mortality; but would pay more attention to the value of the pest damage and the cost of alternative control strategies with or without special consideration of the time involved. Normally he wouldn't want the yield potential of the plants, knowing that maximum protection isn't always worth the expense. In fact, the desire to control pests lingers until he discovers that the benefits more than outweigh the costs. Biologists are largely unconcerned with costs, instead enjoying quantifying apparent yield increases due to control measures.

For almost two decades attempts have been made to reconcile the disciplinary concerns of natural and social scientists for the benefit of farmers and the general public. Improvement of various insect control methods and determination of their physiological effects on crops; Economists depend on entomologists for information about various inputs that combine to produce a specific result. In a way, pest control was designed to bring together the concerns of people from different areas in a more coordinated way. Pest control is defined as an ever-changing process of controlling pest problems through the application (in the storage area) of a commercially viable control or combination of controls that provides the best combination of immediate and long-term results in terms of pest control damage and the absence of unwanted pests. side effects (Beirme, 1967). This implies that pest control can use a one-component tactic or it can be achieved through a complicated integrated pest control system, as previously discussed. Some terms and assumptions in economic analysis:

We begin with an assumption about individual behavior: a rational farmer would maximize profits or minimize costs and seek more in his production decisions than increasing productivity or reducing input consumption. He knows the exact outcome of decisions and the prices practiced on the market.

When analyzing crop protection, it is necessary to define what we invest in and what we achieve with this activity in order to assess whether it is really worth it.

Admission/Cost. Factors of production such as buildings, machinery, materials, labor and managerial skills are known as inputs and when valued at their respective prices are referred to as agricultural costs or expenses. Let x = input quantity and Px = input price. So cost = (Px)(X)

exit/reversal. Through some physical or biological process, the above inputs are converted into usable products or outputs. Likewise, it can be valued at its price to achieve the return, revenue, or utility. The benefit of pest control is reflected in increased yields or increased yields.

Let X = rate of return (increase) and Py = fixed price. So return or sales = (Py)(Y)

pest control. Pest control is becoming increasingly important in our modernizing agriculture as problems with pests and damage increase over time. As input it has 5 components: pest control materials, labor and management or knowledge of pests, expected damage and alternative control methods.

pesticides. Pesticides used to be the single most important means of protecting crops against insects, weeds and pathogens, but due to ever-increasing prices and undesirable side effects, non-chemical methods are being used. However, the continued dependency on pesticides for the foreseeable future is a reality that pest control companies must come to terms with. In general, pesticides are a regular part of the farm's cash spend.

Non-Chemical Control. This method is also known as labor control because it relies heavily on the farmer's manual effort. Non-chemical methods do not necessarily mean that the materials needed to use them are free.

efficiency. We define the most efficient pest control strategy as the one that requires the least combination of labor inputs for a given increase in yield, keeping its factors constant. The definition combines the concepts of “efficiency” and effectiveness presented by Semple (1985). According to him, the effectiveness of an insecticide is the minimum dose required to reduce the target pest population by a specified proportion (80%), regardless of pest pressure. Efficacy, on the other hand, is indicated by the number of surviving insects and the extent of production damage after treatment. It is not determined by the "efficacy" of the insecticides, but by the persuasiveness of the pests as insecticides through general operational procedures. You need to know the compatibility of your control measure with your pest problems, and an effective manager does that.

Ideal sleepers. At least two sets of pest population thresholds can be found in the pest control literature, one overshadowing the other. Studies of plant physiology related to phytophagous organisms show that there is a tolerable level of plant destruction by pests at which the crop can still recover and retain vigor. Apparently, the Economic Damage Level (EIL), sometimes referred to as the Biological Threshold (BTL), is the critical level of pest density that exceeds what is tolerable for crops. Biologists use EIL to justify control measures. For economists, this could never happen if the cost of control were not zero. Economic Threshold Level (ETL) is the pest density level at which suppression action begins, with control costs at least equal to the expected damage value. Some IPM professionals prefer using the term Control Action Limit (CAT) for EIL as it immediately indicates that a level control action is required. The mathematical expression for ETL below gives the basic relationship between the critical level of pest density and economic variables. If we take and K as predetermined variables (constants), then only crop costs and prices affect the ETL. Note the prohibitive nature of the cost control action. If pesticide prices were very, very high, the ETL and control measures might not be economically justified. However, when the harvest is of high value or the market demands high quality produce, the ETL is low and the propensity for control action is high.

ETL = c/PDK

From where
c = cost of the control action
r = Erntepreis
d = damage coefficient
k = elimination efficiency

Partial budgets: a guide to the pest control decision

A private farmer faced with a limited cash and credit budget would think twice about investing money in a biologically attractive innovation. He may not keep a detailed balance sheet of the proposed change, but in the back of his mind he calculates and weighs the relative benefits and costs of each new venture. If the perceived net economic benefit is positive and acceptable, the resource requirements are evaluated and ways to fund them are explored.

Fractional budgeting is perhaps the most popular decision-making tool used by entomologists when conducting applied research to add economic substance to experimental results. yield analysis), but the net increase (decrease) in farm income resulting from a small (proposed) change on the fly. It contains 4 main items that contain precise information about changes in monetary terms, namely: excess income, reduced costs, increased costs and reduced income.

Added value is the value of increased yield and/or the value of quality improvements.

Reduced costs are the value of inputs that are no longer used in the proposed change. If the company used to spend 6 man-days of labor, but the new technology only requires 4 man-days, then the wage that would have to be paid for 2 man-days represents a cost reduction.

Additional costs are the value of additional inputs as a result of the proposed change. This is the exact opposite of reduced costs. The classic example is the added costs of fertilization, labor and machine maintenance associated with modern farming.

Reduced returns are lost production value. If the proposed change reduces yield, it reduces yield. In some cases, the surplus is shared between the owner and the harvester/thresher, so that the value of the harvest they receive is counted as a shortfall.

The partial budgeting process is simple. Analysts only need to know the details of the process change. Using data on market prices, he can assign values ​​to each item that changes and determine whether this reduces or increases returns or costs. Then he can calculate the net change in revenue by subtracting the sum of the additional costs and reduced revenues from the sum of the additional returns and reduced costs:

Net Sales Gain/Loss = (Additional Returns + Reduced Costs) - (Additional Costs + Reduced Returns)

Biological studies of pest control strongly assume that farmers do not control pests; this is the implication of comparing treated plots with untreated plots. Such standardized experimental procedures directly facilitate the computations involved in economic analysis, but at the expense of the intuitive value of the practical content. It does not give the analyst a general and real understanding of the problem situation, since few farmers are currently indifferent to the pests. The increase in pesticide use observed in rice, vegetables and bananas shows that pest control is very active in our agricultural system. More recently, field studies of rice pest control use farmer's practice as a separate benchmark.

It is imperative that analysts look for flexibilities in the data set and shape the structure to the dictates of the local problem situation. In this case he could present a number of problem situations and alternatives. For each situation, the dominant alternative can be decided based on at least 2 criteria: (1) magnitude of net income change (2) resource needs and affordability.

Other decision-making models

In reality, farms are several companies. There are also significant interdependencies in decision-making across cultures and over time. There is also uncertainty or lack of information about pests, damage, controls and prices. In other words, the type of control that the farmer applies to his main crop influences the decision of the second crop control. Likewise, your control practices over the past season will have a major impact on your decision both in the present and in the future. Imperfect knowledge and limited skills about pest control decisions and the presence of natural disturbances can result in actual decisions being "inferior" to those predicted by the fractional budget model. And when trying to develop realistic models, the analysis tools tend to be conceptually complicated and computationally intensive. This leads us to a brief discussion of the various models that have recently been developed.

Whole agricultural budgets. This is just an extension of partial budgets. It recognizes interdependent decisions, meaning that technology adoption in one organization impacts others. This changes the entire agricultural system. It will often be difficult to distinguish cause from effect. Taking the overall system as a unit of analysis makes it easier.

production function analysis. It is essentially statistical information that is widely used in production economics research. A production function provides information about the average relationship between the agricultural product and its factors of production. It contains meaningful estimates of the exact contribution of each input to the total output. Headley (1968) formalized the economics of pest control and applied this framework to the analysis of pesticide expenditure in US agriculture. He concluded that pesticides are actually productive inputs, adding $4 to the value of agricultural output for every $1 spent on them. So in the 1970s he envisioned a growing market for agricultural pesticides and urged workers to develop a less hazardous but comparatively high-yield substitute.

Reichelderfer (1980) criticized the common practice of using pesticides as a proxy for pest levels to account for variations in production. Note that it is the pest and not the control measure that directly affects yield. She pointed out that production functions for pest control are unrealistic unless they express yield as a function of pest levels. Since this practice is necessitated by a lack of data (pest infestation), economists are advised to exercise caution when interpreting the results. On the one hand, the so-called productivity of pesticides depends entirely on pest pressure. Therefore, it is important that economists understand the biological system they are working with.

Cost-benefit analysis. BCA is probably the most comprehensive analysis tool, but unfortunately it requires extensive data and is generally not feasible. BCA treats pest control as an investment or as a cost and revenue pursuit. While time is at the heart of B-Canalysis, which uses discounting methods to calibrate cash flow to obtain timeless measures of efficiency, internal rate of return (IRR), and cost effectiveness (BCR). Ideally, the IRR is greater than the market rate and the BCR is greater than 1. BCAs can be conducted at both farm and community levels. We call the latter Extended BCA. This is of great use in analyzing pollution problems related to pest control, which go far beyond farmers' concerns and yet have a tremendous impact on what is shown below (Table 1).

Room fumigation with PhostoxinR for a warehouse with a volume of approx. 980,000 cubic feet (or 27,750 m³). The amount of corn stored was 147,000 x 75 kg bags or approximately 11,000 tons. The total value of corn at current prices of P2.40 per kilo is P26,460,000.00. Reported loss from Sitophilus granarius (L.) infestations over a three (3) to four (4) month period was 10% to 15% of total weight. In real terms, this corresponds to 1,102,500 kilograms or P2,646,000.00. The cost of fumigation at current prices of P150.00 per 1000 cubic feet is P148,200.00. Equating this value to the potential loss if no fumigation is performed gives a saving of P2,497,000.00.

risk analysis. Finally, the last addition to our list sees pest resurgence as an involuntary risk (as opposed to voluntary game) taken by farmers paying pest control measures as a means of minimizing risk or fluctuations in yields and profits and control costs as premium farmers, to avoid this. This analysis puts less pressure on biological data requirements, particularly on the extent of pest infestation. This type of analysis has the potential to influence pest control policies, particularly crop insurance and pest information services.

We conclude this article by stating that cost-effective pest control research meets our needs. Just as economists try to understand the biological system, the biological science community must also understand the economic system.

Table 1. Cost of fumigation with methyl bromide (MBr) and phosphine-generating formulations (PH3 tablets) for different applications.

where 1 ft³ - 28.3168 liters or 1000 ft³ is 28.3168 m³
P14 = 1 USD

The prices quoted include labor costs, contractor taxes and all other costs related to fumigation. Applies to Greater Manila area only, transportation, meals and lodging for a minimum of three (3) employees must be added.

Quelle: Fumigation Specialists Inc., Aurora Blvd., Q.C.

REFERENCES

Beirme, B. P. 1967. Management of Pragas. London: Leonard Hill-Verlag.

Headley, J.C. 1968. Estimation of Agricultural Pesticide Productivity. america Day. Agricultural eco. 50:13-23.

Headley, J.C. and J.N. Lewis. 1967. The Pesticide Problem: An Economic Approach to Public Policy. The John Hopkins Press. 141 p.

National Academy of Sciences. 1969. Economic Principles of Pest Control. In "Principles of Control of Plant and Animal Pests." NAS, Washington, D.C

Reichelderfer, K. H. 1980. Economics of integrated pest management: Discussion: AJAE 62: 1012-13.

Ruisink, W. G. 1980. Economics of Integrated Pest Management - An entomologist's view of IPM research needs. america J. Agric. Econ. 162(5): 1014-1015

Pattern, R.L. 1986. Entonomics: Economics of Integrated Pest Management. In "Stored Grain Pests and Their Control". Vol. 9. IPM Part I

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