An Introduction to Integrated Pest Management
Integrated Pest Management (IPM) is a well-known innovation that accords with modern sustainable environmental management principles. Farmers and consumers in developing countries are too often faced with a serious dilemma: they must either sacrifice a significant share of their crops to pests or use highly toxic pesticides that can harm human health and the environment. For solving this dilemma, making a major contribution for the improvement of food security, eradication of starvation, and alleviating poverty IPM is introduced which associated with the developed countries of the world are supporting integrated pest management (IPM) to ensure good practice. IPM succeeded in developing environmentally sound practices, but struggled to communicate the value of information on the risks and benefits of IPM. The slow adoption of IPM is often attributed to the widespread gaps between farmers� knowledge and understanding of the complex and controversial issues surrounding pesticides and IPM. Integrated Pest Management is a process involving common sense and sound solutions for treating and controlling pests. These solutions incorporate three basic steps: 1) inspection, 2) identification and 3) treatment. Treatment options vary from sealing cracks and removing food and water sources to pesticide treatments when necessary. IPM, as a partnership between homeowner and pest professional, can help protect human�s family against pest-associated health, property and quality of life threats. This paper addresses IPM and risk assessment not only from the economic, environmental and public health perspectives, but also from a communication and consensus-building point of view.
Introduction
Costly experience with the conventional pest control approach and the associated problems resulting from an exclusive reliance on chemical control led to the development of the integrated pest management (IPM) strategy. Sole reliance on a chemical control strategy, preventive use or calendar spraying, treatment at the first sign of pest, little or no evaluation of the treatments, and lack of a system-wide perspective and its negative impact on the surrounding atmosphere caused many people to ask "Is there any better way?" IPM was developed to address some of these concerns. Integrated pest management is a decision-making process for determining: If you need pest suppression treatments? When you need them? Where you need effective, environmentally sound control? IPM is now widely used in a number of countries, e.g.., Indonesia, United States, etc. In an IPM program, the objective of the treatment is not to eradicate pests but to suppress pest populations below the level at which they cause unacceptable damage. The goal is to effectively control crop and forest pests on a sustainable basis, at an acceptable cost and with minimal detrimental effect to the physical and human environments.IPM, or Integrated Pest Management, is a strategy of managing pests that is designed to meet an individual's production goals in the most economically and environmentally sound manner possible using a combination of control tactics. IPM is a systematic, information-intensive approach which depends upon an understanding of the entire production system. It strives to use several complimentary tactics or control methods to manage pests which make the system more stable and subject to less production risks. IPM focuses on tactics that will prevent or avoid anticipated pest problems rather than remediate problems once they have occurred. Implementation of IPM requires a working knowledge of the basic tools available for pest control. It also requires on-going education about the pest complex, and maintaining the delicate balance between pests and beneficials. It further requires the use of the proper tools at the proper time to ensure that harmful pesticides are not used prior to the need to maintain pest population�s level below an acceptable economic threshold. Implementation of IPM concepts cannot occur until a degree of information about the pest population is obtained, which requires frequent and periodic monitoring and analysis. Additionally, the implementer must have a working knowledge of the pest itself, including proper identification and an understanding of the life cycle of the pest. Implementation of IPM principles will naturally include monitoring (scouting) of fields or areas subject to pest infestation. Monitoring involves scouting for the pest, as well as determining natural pest enemies (beneficials). Population numbers are calculated, and environmental factors such as weather are considered (i.e. some pests are more prone to attack plants exhibiting drought stress).
Approaches to Pest Management
Prevention - When a pest problem is anticipated and action is taken to prevent a significant problem from occurring, the approach is termed prevention. The action taken may include any applicable method proven to prevent or reduce the probability of a significant pest problem from occurring. The prevention approach may include either chemical or non-chemical methods.
Approaches to Pest Management
Prevention - When a pest problem is anticipated and action is taken to prevent a significant problem from occurring, the approach is termed prevention. The action taken may include any applicable method proven to prevent or reduce the probability of a significant pest problem from occurring. The prevention approach may include either chemical or non-chemical methods.
When a corn grower applies a granular soil insecticide at planting time, it is assumed that the treatment will prevent a significant loss in yield due to the presence of soil insect or nematode pests. When a grain manager cleans and treats an empty bin to eliminate sources of insect infestation, it is assumed that the action will reduce the probability of serious insect infestations at a later point in grain storage. When a grower applies a preemergent herbicide before any weeds appear, it is assumed that weed seeds are present and the treatment will prevent emergence of the weeds as the season progresses.
Suppression - After a pest problem has been detected, any action taken to suppress the pest population is termed a suppression approach. In practice, few treatments totally eliminate a pest problem, but the pest population is reduced to a point at which it is no longer perceived as a problem. Thus, any action ranging from treatment of a corn borer infestation on corn to treating the family pet for fleas may be regarded as suppression. Post emergence application of herbicides to reduce emerging weed populations is regarded as suppression. The use of chemical methods is generally associated with suppression practices, but non-chemical methods may also be employed to suppress a pest problem. For example, a grain manager may alter the temperature of a grain mass and significantly reduce insect infestations.
Eradication - When a pest problem must be totally eliminated from a designated area, the approach is termed eradication. If a new pest such as the Mediterranean fruit fly is detected in a fruit growing area, regulatory agencies may implement widespread actions to totally eliminate the pest problem before it becomes established to a point that it can no longer be eradicated. When a serious insect pest problem is detected in a commodity of foreign origin, fumigation tactics may be employed to totally eliminate the presence of the unwanted pest from stock identified as infested. If a pest population of public health importance is detected in a hospital or food establishment, efforts may be taken to totally eradicate the pest population. In general, the eradication approach does not apply to elimination of an established pest population from a large area.
Pest Management Methods
Pest management practices are grouped under various method categories including (1) biological, (2) chemical, (3) cultural and mechanical, and (4) legal. Additional categories may be defined, but we will attempt to group most practices under the four mentioned.
Biological Control - Biological control generally includes the manipulation of one biological organism to control another organism classified as a pest. In the web of nature, the combination of biological control techniques is extensive. Insect pests may be preyed upon or parasitized by other insects. Most insect pests are attacked by bacterial, fungal or viral pathogens. Specific weeds may be controlled by insects with specialized feeding habits.
The implementation of biological control methods has been categorized into three basic approaches, namely: (1) classical, (2) augmentation, and (3) natural.
When a pest is found to not be native to a given area, it may be assumed that the biological organisms that regulated its population dynamics in its native environment are lacking. In such a situation, the classical approach of biological control is employed to (1) determined the pest's native home, (2) locate beneficial organisms that naturally control the pest organism in its native area, and (3) if feasible, import, multiply, release and establish the beneficial organisms in the problem area to facilitate biological regulation of the pest problem. If successful, the importation and establishment of the beneficial organisms will result in a long term reduction of the pest problem and repeated releases of the beneficial organisms will not be required. Key examples of such accomplishments classical biological control applicable to Ohio include the control of the Cereal leaf beetle on oats and the alfalfa blotch leafminer on alfalfa by the release and establishment of beneficial parasitic wasps. The process of importing and releasing beneficial organisms is complex, since many precautions must be taken to prevent the introduction of organisms that may have adverse effects.
When beneficial biological organisms are mass reared and released periodically to supplement the natural enemy complex and achieve reduction of a pest problem, the approach is called augmentation. This approach may be applied to pest populations that are either native to the area or of foreign origin. In general, augmentation may be considered when it is economic and feasible to rear, multiple, and release a natural enemy of a pest to the point that reduction of the pest problem is achieved. Successful augmentation efforts have been developed for greenhouse environments where altering the balance between a pest and its natural enemy is feasible. A number of corporations are currently investigating techniques of applying parasitic nematodes to turf for control of soil pests. Application of the augmentation approach to field crops is limited, but a major effort is underway in South Africa to control the Eldana borer on sugarcane via augmentative releases of parasites.
Most pest populations are maintained by a number of natural predators, parasites and diseases, which represents natural biological control. If such forces were not in effect, we would be overrun by pest populations. The balance of crop pest populations and their natural enemies can be significantly influenced by cultural practices and the use of chemicals. Populations of natural enemies can be enhanced by selective use of cultural practices or decimated by indiscriminate use of pesticides. In some cases, pesticides have been developed that effectively control a pest population without having a significant effect on beneficial species. A new pesticide for control of alfalfa weevil is currently approaching registration that effectively kills weevils without harming beneficial parasitic wasps and pollinating bees. An example of natural control research in Ohio includes studies on the impact of predatory ground beetles on early pests of corn such as cutworms and armyworms. One study suggested that the efficacy of a given soil insecticide to reduce cutworm damage may be related to the lack of toxicity of the compound to the ground beetles that prey upon cutworms.
The potential for development of biological controls for a wide range of pest problems is significant. However, development of successful biological control technologies often requires significant investments into research that may or may not readily produce satisfactory results. To date, biological control has not been a marketable product like chemical controls and research efforts into the field have been limited. Furthermore, implementation and evaluation of biological controls are often more complex than that of chemical methods.
In summary, classical and augmentative biological controls are not available for very many pest problems - especially severe pest problems that demand immediate attention. However, natural biological control is in effect in most situations, and it is important that every effort be implemented to enhance such biological activity wherever it exists.
Chemical - Pesticides are the most readily recognized method of pest management. The institution of the pesticide industry is a relatively recent development of the last half of the 20th century. The evolution of pesticide products changes significantly with each decade. Advancements in the development of biological pesticides may alter the field significantly. The range of risks and benefits attributed to pesticides will remain a key issue of society. The use of pesticides will remain as a dominant method to be incorporated in future pest management programs.
Cultural & Mechanical - Prior to the advent of chemical pesticides, humanity relied primarily on cultural and mechanical methods of pest management. With the development of pesticides, the relative impact of various cultural and mechanical practices on pest populations was often overlooked. As public interest in environmental issues expands, the impact of cultural and mechanical pest management practices is receiving greater attention.
Crop rotation, tillage practices, barriers, hedge rows, traps, and other forms of environmental modifications all influence the incidence of pest problems. Crop host resistance to pests - which may be considered a cultural practice - remains a key factor in many pest management programs. Sanitation is the basis for pest management in most livestock, public health and food establishment pest management programs. Sanitation is also applied to crop production when removal of sources of pest populations is a critical factor.
Examples of cultural and mechanical practices in pest management are abundant. Every time a grower rotates a crop or tills the land, weed, insect, nematode, slug and disease pest problems are affected.
Legal - Regulatory actions are often employed to prevent immigration of foreign pests or to prevent the dispersal of established pests. Such actions are termed legal methods of pest management. Fruit and other perishable products being carried in to the USA by travellers are confiscated to prevent entry of pests. California prohibits transport of apples from northwest counties into the remainder of the state by posting quarantine signs to prevent the spread of apple maggot. New York prohibits movement of gravel from counties bordering the eastern shore of Lake Ontario to prevent the spread of the alfalfa snout beetle. Imported animals are often held in quarantine for a period of time to allow inspection for pests and diseases. Such legal actions are not always effective, but they enable interceptions of many pests that could add to the pest problems already present in the county.
Benefits of IPM
There are many benefits to introducing IPM in schools and childcare centers. IPM not only provides wonderful opportunities for environmental education, it is also an essential aspect for the sustainable management of any school or childcare centre in the 21st century. Perhaps the most urgent reason for introducing IPM is to minimize the unnecessary use of pesticides to better protect community health and the environment from pesticide exposures. As the community is becoming more aware and concerned about the dangers of chemical exposure they are demanding safer environments. Employers have a duty of care to provide safe working environments. Governments have responded by ensuring chemical risks are assessed and minimized under occupational health and safety legislation and hazardous substances regulations. Yet, many schools and childcare centers still needlessly use hazardous pesticides when safer alternatives exist. Schools and childcare centre have many responsibilities to ensure the safety of children in those environments. Childcare centers are licensed and as part of the licence requirements, they must be 'free of vermin'. It is important to note however, that this does not mean that regular pesticide applications need to occur. Rather, a regular pest status audit and localized treatment for any infestations fulfils legal requirements and pest management objectives. IPM is ideally applied at the design stage of any construction, as it is far cheaper and more effective to 'build out' pests than to implement IPM retrospectively. Australia for instance, leads the way in the use of low-risk termite design and non-chemical termite barriers using materials such as granite and steel mesh. New schools and childcare centre are now being built using non-chemical methods for termite protection. The next stage is to apply IPM for the full range of common pests in schools and childcare centre.
Reducing Pesticide Exposure and Risk
Everybody is exposed to pesticides to varying degrees. We are exposed to pesticides through eating food or drinking water contaminated with pesticide residues, inhaling pesticide vapours, and absorbing or ingesting residues from carpets, benches, soil, etc.
There is an urgent need to reduce pesticide exposure and the pesticide load in our bodies and environment. By adopting integrated pest management, the risk of pesticide exposure from this source will be reduced, as will residues around our homes and the environment. As with antibiotics, hazardous pesticides should never be overused or applied as a 'preventative' measure, they should only be used in emergency situations or as a last resort if other IPM methods have not been effective.
What is a pesticide?
The term 'pesticide'is legally defined in Commonwealth and State legislation under the Agricultural and Veterinary Chemicals Code Act 1994, commonly referred to as the 'Agvet Code'. The term 'pesticide'includes insecticides, herbicides, termiticides, fungicides, rodenticides, and even disinfectants that are used to kill, repel, or attract pests.
Reasons for Adopting IPM
- Provides environmental education opportunities
- Contributes to sustainable school and childcare centre management
- Minimizes pesticide exposure - especially of children
- Protects human health from pests that may spread disease
- Saves valuable school resources and reduces pest control costs
- Limits potential liability
- Protects and enhances the school environment and surroundings
- Protects wildlife from pesticide exposures and reduces environmental pollution
The Base Components of IPM are:
� Prevention: Crops and plants should be grown in a way to maximize the health of the plant. Healthy plants are able to withstand more pressure from insect pests and disease.
� Monitoring: Regular and systematic monitoring is done to determine damage to the plant and pest population and whether these values are increasing or decreasing.
� Identification: Pests and diseases must be correctly identified before treatment options can be determined.
� Threshold Determination: For agricultural crops, this is often an economic threshold; for home gardeners, this threshold is determined by how much damage the plant can withstand.
� Treatment: Least toxic options are chosen first. These include cultural, biological, and physical methods.
� Evaluation: Monitoring is continued after treatment to determine efficacy.
How to Implement IPM
Establishing an IPM program in schools and childcare centres is like climbing a ladder. It needs to be approached one step at a time, without jumping to the top of the ladder, as this creates an unstable foundation. When we implement a new system, often we only partially implement it, and when it fails we quickly revert to the old ways claiming the alternative doesn't work. But IPM does work and has been successfully introduced into hundreds of schools in the USA and a growing number of schools across Australia. IPM takes pest control out of the realm of buying a 'readymade' solution and puts the process back in the hands of the people in the environment where pest management is needed. A fundamental shift in thinking and managerial approach is required. To ensure IPM is successfully adopted, support for the program is required at all levels in the school community, however support from management is essential if the program is to substantially get off the ground. IPM can be effectively integrated with other managerial responsibilities such as preventative maintenance, cleaning, landscaping, education programs and staff training, which are all key elements in an IPM program.
Steps for Successful IPM
A key question that needs to be asked before any pest control occurs is: Is it a real pest problem or a perceived pest problem? If there is no real pest problem but a perceived problem, then education and monitoring data can be used to provide reassurance. If there is a real pest problem, then IPM strategies can be applied. This is especially important in environments where there are many people who have different tolerance levels to pests. Establishing an IPM program may appear like a lot of extra work in an already busy schedule, and a costly process within an already stretched budget, but remember you don't have to start from scratch, enough information has been provided here to start immediately! Experience has shown schools which implement IPM programs are likely to realize cost savings within a relatively short period of time. There are, of course, many educational, health and environmental benefits from establishing a safer and more eco-friendly pest management regime.
Step 1: Develop an IPM Policy
Step 2: Designate pest management roles
Step 3: Establish pest management objectives
Step 4: Inspect, identify and monitor pest problems
Step 5: Set action thresholds
Step 6: Apply IPM strategies
Step 7: Evaluate and record results
Step 1: Develop an IPM Policy
Developing an IPM Policy is an important first step in making the change from conventional pest control to an IPM program. An IPM policy should clearly state the aims and objectives of the program, the decision-making process, and guidance for the education and involvement of the school community in the IPM program. It is not uncommon for a new approach in an organisation to be driven by a champion, which, if he or she leaves, may mean the program falls apart. The IPM policy is a useful communication tool to ensure that staff changes do not diminish the program and that contractors, parents, staff and children are aware of the IPM policy and requirements.
A Model IPM Policy includes:
� Preamble
� Policy aims and objectives
� Definitions
� Legislative requirements
� IPM procedures and strategies
� Performa notices and action plans
� Educational opportunities
� Meeting procedures
� Record keeping requirements
� Notification of pest control procedures
� Emergency pesticide use protocol
� Pesticide use in IPM programs
� Storage of hazardous substances
� Contracting a pest manager
"Our beautiful school nestles into the foothills of the Blue Mountains outside Sydney. We have been fortunate enough to ensure our school environment is safe and free from pesticide contamination because of our Pest Management Policy, which was finalised and implemented in 1996. The process of establishing the Pest Management Policy began in 1993, when I attended my first Parents and Citizens Association meeting. It had come to my attention that Comleroy Road Public School was relocating to a new site and I saw this as anopportunity to ensure that from the ground up, the best possible IPM practices were implemented. I spoke with the Principal at length about my concerns and ideas prior to the meeting. At the meeting I spoke considerably about the safety issues associated with pesticides and their use around children. I also spoke about the opportunity and obligation we had to protect our children from pesticides by finding safer alternatives. To my surprise, the audience was in total support and unanimously agreed this was an issue of importance and one which needed to be addressed further. The door was opened, and a long and sometimes difficult journey began into preventing pesticide use at our school and changing people�s perceptions of insects and what a pest problem actually constituted.The first step was to draft a Pest Management Policy, organise professional backup for it, and arm myself with alternative solutions and preventative measures to avoid chemical use. While implementing the policy over the last seven years, I have been fortunate enough to make contact with many incredible and dedicated people who are committed to protecting our children and environment from pesticide contamination. Most notably, Dr Kate Short, then Co-founder of the National Toxics Network, who shared her vast knowledge and experience with me, and encouraged and supported us whilst we established the policy. Establishing such a policy has many minefields. For decades we have been bombarded with propaganda from chemical manufacturers that insects are dirty, dangerous, disease riddled pests that need to be exterminated and the majority of our population unfortunately believes this. Thankfully, I had total support from most of the P&C and staff with only a few sceptics who doubted the effectiveness of non-chemical methods. When our children are being taught about the wonders of ecology and the world we live in, they also must see it living in the playground. For instance, spiders and their webs are natural, they are not dirty or messy. Those spiders catch and eat other insects, such as mosquitoes and, in turn, they are eaten by little insectivorous birds, such as the shrike-thrush or yellow-breasted robin. We must also realise that to poison the smallest of insects could impact on the food chain all the way through to us".
Step 2: Designate pest management roles
Communication between the people involved with the IPM program is the key to its success. When the respective roles of all people in the IPM program are designated, and there is good communication between occupants (students and staff), parents or guardians, pest managers and decision-makers, it will be possible to achieve the pest management objectives. The 'pest manager' is most likely to be a contracted pest control operator who is trained and licenced, but in some circumstances could also be the school principal, a designated staff member, or a parent. If a contracted pest manager is carrying out your IPM program, it may be necessary to appoint an IPM co-ordinator to oversee the IPM program in the school or childcare centre.
The importance of education
Education is the key to people understanding the goals of the IPM program and their roles within it. The school community should be educated to understand the basic concepts of IPM, and how the principles will be applied in their workplace. People must know who to contact with questions, or how to report pest problems. It is also beneficial to incorporate aspects of the IPM program into the curricula and environmental education programs.
Step 3: Establish pest management objectives
Pest management objectives, by necessity, will differ from site to site within the school or childcare centre, and these differences need to be considered before setting action thresholds in Step 5. For example, with buildings or structures, the objective may be to minimize structural damage from termites. For ornamental gardens, the objective might be to maintain aesthetic value, while for a sporting field; it may be to maintain a specific playing surface.
Examples of general pest management objectives:
� Manage pests that may occur to reduce interference with the learning and teaching environments
� Eliminate injury to students, staff and other occupants
� Preserve the integrity of the school buildings and structures
� Provide a safe and healthy environment
Step 4: Inspect, identify and monitor pest problems
An IPM program consists of a cycle of inspecting, identifying, monitoring, evaluating and choosing appropriate IPM strategies. Routine inspection and accurate identification of pests are vital steps to ensure control strategies are effective.
Inspecting and monitoring for pests involves:
� Checking areas for evidence of pests
� Finding entry points and harborage sites
� Locating food and water sources
� Estimating pest numbers
Step 5: Set action thresholds
An action threshold is the point at which the presence of a pest triggers an action. It is based on the tolerance levels for each pest, and includes consideration of the pest management objectives (Step 3), any sensitivity to the pest or treatment strategy, injury or damage potential, which includes economic, medical or aesthetic damage. The presence of some pests does not in itself necessitate action, but when pests exceed action thresholds, a response is needed.
Step 6: Apply IPM strategies
Common organisms that can be encountered in schools and childcare centres which may require management include: mice; rats; cockroaches; silverfish; ants; flies; bees; birds; mites; wasps; spiders; termites; and borers. Site-specific pest management strategies need to be developed by the pest manager. To ensure maximum effectiveness, the timing of treatments should take into account the life cycles and seasonal variations for each organism as well as its natural enemies. IPM treatment strategies fall into two major categories indirect and direct and are required for both indoor and outdoor pest problems.
Indirect treatment strategies:
� Design/Redesign - e.g. fences with metal supports and palings off the ground to minimise the risk of termite attack;
� Habitat Modification - e.g. sealing cracks and crevices in kitchens and bathrooms reducing cockroach breeding areas;
� Education - e.g. improved sanitation and waste recycling reduces attractiveness to many organisms.
Direct treatment strategies:
� Physical/mechanical controls e.g. traps to catch and monitor cockroaches and rodents;
� biological/microbial controls - e.g. release of lacewings to control aphids or the use of Bacillus thuringiensis, a microbe to control caterpillars;
� Least-hazardous chemical controls e.g. repellents, insect growth regulators, pheromones, botanical pesticides.
Step 7: Evaluate and record results
Accurate record keeping is essential to an IPM program. Records allow the analysis of results to determine if pest management objectives are being met. Accurate records also assist in decision-making processes and ensure the IPM program is well documented when changes in staff or contractors occurs. Records of inspecting, identifying, and monitoring activities show changes in the site environment, physical changes, pest numbers and changes in any damages or loss. Importantly, records also show your successes! A complete and accurate log should be maintained for each property and kept in a central location for easy access by the pest manager. If pesticides are used, records must be kept in accordance with requirements of the state regulatory agency. Records are best kept in the same format to allow easy access over time and graphing to show trends. New law for keeping records of pesticide use in NSW A new regulation under the NSW Pesticides Act 1999 called the Pesticides Amendment (Records) Regulation is now in operation. If you use pesticides on your produce or farm, or in your business or occupation, then you must make a record of your pesticide use.
The record must contain the following:
� Who applied the pesticide
� What was applied
� When, how and where it was applied
� What it was applied to
� How much was applied
� If the pesticide was applied outdoors by spray equipment, an estimate of wind speed and direction.
The law applies to users of pesticides including farmers, market gardeners, green keepers, nursery operators, landlords, pest control operators, landscape gardeners, local councils and government agencies that use pesticides. The record must be made within 24 hours of use and kept for three years. NSW Environment Protection Authority (EPA) officers may check these records at any reasonable time and penalties may apply if the records have not been kept in accordance with the law. A sample record keeping form is available from the EPA.
Getting Started With the Biological Control Component of IPM
The stages outlined above provide a framework for the adoption of IPM. The points below need to be considered to implement Stage 3:
- Seek specialist advice from suppliers of BCA's and consider employing an IPM crop monitoring specialist*.
- Monitor crops regularly and learn to identify your pests and beneficial while doing so.
- Determine what level of pest you can tolerate.
- Replace broad spectrum sprays with biological or more selective insecticides if available.
- Identify any local BCA's that are likely to assist you - these can be very significant.
- Determine which mass produced BCA's are suitable for your pests, crop and district.
- Determine the best times for introducing natural enemies.
- Ensure chemical residues have had time to disperse before introducing BCA's.
- Identify other practices which will assist establishment of BCA's. e.g. wind breaks.
- If appropriate, reorganize plantings and location of plantings to facilitate use of BCA's.
- Experiment with part of the crop or one planting.
*Many of the suppliers of bicontrol agents also provide commercial monitoring services.
IPM systems consist of numerous elements with monitoring usually described as the "cornerstone of IPM". Biological controls, cultural practices, nutrition and irrigation management are all important elements.
The degree to which biological control agents (BCA's) can be utilized will vary from crop to crop and from area to area and will depend on the answers to a series of questions. For example:
- Are there effective natural enemies for the major pests of this crop?
- Effective natural controls exist for some pests but not others.
- Are these mass reared for introduction or do they enter the crop from local populations?
- This will influence management practices. eg. Conservation of refuges or alternative crops.
- What crops or types of vegetation are adjacent to the target crop?
- Some crops act as refuges for natural enemies while others can harbor unwanted pests.
- Is the crop being grown under "organic" or "conventional" classification?
- If the crop is "organic" this can provide added incentive to use biocontrol methods
- While a crop does not have to be grown organically to make use of biocontrol methods.
- Are there "soft" chemical options for use in conjunction with natural enemies?
- Soft options are available for some pests and not others.
- Is the crop life span and environment suitable for natural enemies?
- It can be difficult to establish BCA's in short lived crops.
- Are certain plant life stages suitable for natural enemies and others not?
- BCA's may be most appropriate at a particular stage of the growing cycle.
A crop consultant versed in biological control options will help you answer these questions so that an appropriate program will evolve. Each farm and crop has unique characteristics which need to be catered for in developing a program and responding to events as the season progresses. In addition to these questions are those related to cost and practicality and the degree of difficulty controlling key pests with chemical means alone. Do not assume that it is more expensive to use biological control methods.
BCA's can be used in various ways. These methods are usually divided up into the follow categories:
Inoculative release: One or two releases early in pest infestation to control pest gradually. e.g. predatory mites in strawberries, Trichogramma in outdoor crops, lacewing in field and greenhouse crops.
Regular or dribble release method: Regular small release during likely problem periods, used like preventative fungicides. e.g. P. persimilis is nursery crops, Encarsia in green house crops.
Inundative releases: Repeated high rate releases during periods of pressure for quick knock down. e.g. Cryptolaemus beetles, Trichogramma in green house crops, P. persimilis for dosing hot spots of TSM.
Combination of above methods: e.g. initial high release rate for quick knock down followed by regular targeted small releases.
Methods of releasing biocontrol agents
Biocontrol agents are released using a wide range of methods.
- Some are placed in the crop as adults (aphytis wasps),
- Some as pupae in moth eggs (trichogramma).
- Some use a card or capsule system (trichogramma, encarsia)
- Some in sachels with food (cucumeris, montdorensis)
- Some are spread loose or in a carrier (persimilis in vermiculite, lacewing eggs and larvae in chaff).
Talk to your supplier about the best strategy and release methods for your crop and situation.
Numerous benefits arise from utilizing natural enemies. Some are obvious while others are more hidden and difficult to quantify:
� BCA's assist in control of some important pests which have developed high levels of tolerance to chemical products - e.g. two spotted mites, Heliothis, cabbage moth.
� In combination with soft options, BCA's help to prolong the useful life of the remaining effective chemicals - fewer pests are subjected to the chemical and pests that escape the chemical have a good chance of being eaten by a BCA.
� Some BCA's are mass produced. Reductions in chemical inputs necessary for mass release of BCA's also enables movement of local beneficial into the crop. Some of these can be very significant in their own right.
� Natural enemies can enable control of pests in crops sensitive to chemicals.
� Reduce problems with withholding and worker re-entry periods.
� Minimize chemical residues in the end product and the environment generally.
Difficulties encountered moving to IPM
� Practices and routines need to be modified and new information absorbed by the practitioners. The following are some areas that are likely to be important:
� Regular monitoring is necessary to identify pest outbreaks and their location within a crop. It may take time to develop suitable procedures and routines.
� "Soft" controls for some pests are available but not for others. If unavailable, spot spraying with broad spectrum products may be more appropriate than widespread spraying.
� Some damage from pests may need to be tolerated. Some pests may be required to support a useful population of the natural enemy.
� Good timing is necessary when introducing natural enemies - not too early, not too late. For example: You may need to target moth flights, or detect early signs of a pest etc.
� Need to get natural enemies established quickly. If introducing mass reared BCA's, introduce appropriate numbers to facilitate quick establishment.
� Deciding when to or not to spray can be difficult. If soft options are available for the pest in question this is not such an issue.
� Providing a suitable environment. Very hot dry conditions are not conducive to some BCA's. Adjustments may need to made to favor BCA's, e.g. shade, windbreaks, overhead watering.
� Having an expectation that one cannot spray chemicals at all is incorrect and may result in failure of the IPM system. BCA's usually recover from occasional sprays of moderately toxic products and can remain at useful levels.
Elements of an IPM Strategy
A pest management strategy is a series of planned activities aimed at preventing or suppressing pest populations based on ecological principles. IPM takes advantage of the fact that combined strategies for pest management are more effective in the long run than a single strategy. The major pest control strategies that may be considered are:
� Cultural control (traditional, often centuries-old agricultural practices, such as crop rotation; use of resistant varieties; use of trap crops like marigold and crotolaria against nematodes; enhancement of ecosystem diversity; design of the agriculture system; etc.)
� Biological control (natural and artificially produced predators, parasites, and diseases; using plant products; conservation of the nature' enemies of the pest through proper selection of materials, and timing and placing of treatments)
� Mechanical control (direct mechanical action such as fences, creating block and screen; reduction of pest harborage, food or other life support requirements)
� Human behavior change (education about the effect of hazardous pesticide; creasing awareness at all levels: farmers to policy makers, each); and desired behavior of extension worker.)
� Physical control (barriers; traps; mechanical action; manual removal; temperature; moisture; sound; light; etc.)
� Chemical control (Pheromones and other attractants to lure/confuse the pest; using insect repellents; using safe pesticide, i.c., pesticides based on plant derivatives or pesticides from organic formulations)
Points to Consider in the Selection of Pest Management Strategies
� Promote the utilization of locally available, proven and cost-effective, non-chemical pest control methods
� When pesticides are used, promote the utilization of the least toxic (indicated by a color code), cost effective chemical products which are locally available
� promote the use of "selective" over "broad-spectrum" pesticides (the latter kills more than the targeted pest)
� promote reduction in the use of environmentally persistent products (which build 'up in the food chain and environment over decades)
� need-based use of chemical formulations, rather than regular calendar spraying
� prohibit the use of pesticides banned in the country and those classified by WHO as "extremely" or "highly hazardous"
� takes into account national resources, priorities and values, e.g., national and farmer security.
Some Alternatives to Chemicals for Small-Gardeners
1. Tobacco extract: boil midribs and young leaves, soak for 5-6 days and spray (1:4). Controls a wide range of chewing and sucking type of insects.
2. Titepati: using titepati as mulch reduces the attack of soil insects and its leaf extract controls the aphids and caterpillar. Concentration 1:3.
3. Tulsi: decoction of fresh tulsi leaves controls most of the sucking and chewing pests.
4. Cow urine: a mixture of fresh cow urine (1 part) and water (4 parts) is effective against sucking insects.
5. Sisno: one part fermented extract (after 7 days) in four parts of water of young sisno leaves and twigs are effective against ants, aphids, caterpillars, etc.
6. Wood ash: effective against a number of pests. Fresh (not hot) ash., if dug into the soil, controls maggots. A spray of ash in the morning is found effective against aphids.
7. Tomato extract: boiled leaves and stems if applied at a ratio of 1:2 controls caterpillars of cabbage.
8. Mixture of Brew: roots, stems and leaves of as many aromatic herbs as possible, e.g., garlic, onion, pepper, mint, mustard, etc. Brew the mixture and allow fermenting for about 7 days. Add liquid detergent for better spreading. This is effective against most of the common pests.
9. Kerosene and soap spray: 1/4 cup of soap, 1/4 tablespoon kerosene, and mix with one liter of water and spray.
10. Garlic and marigold: 3-4 cloves garlic, 2-3 small onion, 2 handfuls of marigold leaves and pepper (2), bring to boil, mix with 4-5 times water and spray. It controls many of the sucking pests.
11. iNeem extract: as published in various books
The Integrated Pest Management Strategy
The management of insect pests rarely relies on a single control practice; usually a variety of tactics are integrated to maintain pests at acceptable levels. The goal of integrated pest management is not to eliminate all pests; some pests are tolerable and essential so that their natural enemies remain in the crop. Rather, the aim is to reduce pest populations to less than damaging numbers. The control tactics used in integrated pest management include pest resistant or tolerant plants, and cultural, physical, mechanical, biological, and chemical control. Applying multiple control tactics minimizes the chance that insects will adapt to any one tactic. The definition for integrated pest management most relevant to this guide comes from Flint and van den Bosch (1981): "An ecologically based pest control strategy that relies heavily on natural mortality factors and seeks out control tactics that disrupt these factors as little as possible."
Ecological basis
Integrated pest management requires an understanding of the ecology of the cropping system, including that of the pests, their natural enemies, and the surrounding environment. As discussed previously, knowledge about the ecological interrelationships between insects and their environment is critical to effective pest management. This guide emphasizes interrelationships between pest species and their natural enemies.
Economic threshold and sampling
The decision to use an insecticide, or take some other action, against an insect infestation requires an understanding of the level of damage or insect infestation a crop can tolerate without an unacceptable economic loss. The level of infestation or damage at which some action must be taken to prevent an economic loss is referred to as the "economic or action threshold." Action thresholds are available for many vegetable crops. Ideally, these thresholds adjust for changes in market prices, stage of crop growth, cost of pesticides, etc., but in reality most are based on fixed infestation or damage levels.
To estimate the severity of pest infestations, the crop or garden must be sampled. Sampling may entail examining plants and recording the number of pests or amount of damage observed, or traps may be used to capture the pest species to estimate pest abundance. Sampling is conducted at regular intervals throughout the season or during critical stages of crop growth. These sampling techniques, used either alone or in combination, estimate how closesthe infestation or damage level is to the economic threshold.
Integrated Pest Management Control Tactics
� Pest-resistant crops
� Cultural Control
� Physical and Mechanical Control
� Chemical Control
Pest-Resistant Crops: One of the mainstays of integrated pest management is the use of crop varieties that are resistant or tolerant to insect pests and diseases. A resistant variety may be less preferred by the insect pest, adversely affect its normal development and survival, or the plant may tolerate the damage without an economic loss in yield or quality. Disease-resistant vegetables are widely used, whereas insect-resistant varieties are less common but nonetheless important. Examples include varieties of wheat which have tough stems that prevent development of the Hessian fly and cucurbits (squash, cucumbers, melons) that have lower concentrations of feeding stimulants (cucurbitacins) for cucumber beetles. Commercial corn lines with increased concentration of a chemical called DIMBOA display resistance to European corn borer, a major pest throughout the world. In the case of cabbage, the only reliable method of controlling onion thrips is through the use of resistant varieties. Advantages of this tactic include ease of use, compatibility with other integrated pest management tactics, low cost, and cumulative impact on the pest (each subsequent generation of the pest is further reduced) with minimal environmental impact. The development of resistant or pest-tolerant plant varieties, however, may require considerable time and money, and resistance is not necessarily permanent. Just as insect populations have developed resistance to insecticides;populations of insects have developed that are now able to damage plant varieties that were previously resistant.
Cultural Control: There are many agricultural practices that make the environment less favorable to insect pests. Examples include cultivation of alternate hosts (e.g., weeds), crop rotation, selection of planting sites, trap crops, and adjusting the timing of planting or harvest. Crop rotation, for example, is highly recommended for management of Colorado potato beetle. The beetles overwinter in or near potato fields and they require potato or related plants for food when they emerge in the spring. With cool temperatures and no suitable food, the beetles will only crawl and be unable to fly. Planting potatoes well away from the previous year's crop prevents access to needed food and the beetles will starve. The severity and incidence of many plant diseases can also be minimized by crop rotation, and selection of the planting site may affect the severity of insect infestations. Trap crops are planted to attract and hold pest insects where they can be managed more efficiently and prevent or reduce their movement onto valuable crops. Early planted potatoes can act as a trap crop for Colorado potato beetles emerging in the spring. Since the early potatoes are the only food source available, the beetles will congregate on these plants where they can more easily be controlled. Adjusting the timing of planting or harvest is another cultural control technique. The earlier planted processing tomatoes grown in the western United States are far less likely to be infested by the tomato fruit wormthan those planted later in the season. It is also important to use pest-free transplants. Some vegetable crop transplants can be infested with insect pests, and growers using these transplants are put at a considerable disadvantage.
Physical and Mechanical Control: The use of physical barriers such as row covers or trenches prevents insects from reaching the crop. Row covers can help prevent early-season damage to cucurbits by cucumber beetles, and plastic-lined trenches are effective in trapping large numbers of dispersing Colorado potato beetles in the spring and fall. Cold storage is also considered a physical control and, although it does not necessarily kill the insect pests, it at least stops their development and further feeding on the stored crop. Other methods include hand picking of pests, sticky boards or tapes for control of flying insects in greenhouses and various trapping techniques.
Chemical Control: If all other integrated pest management tactics are unable to keep an insect pest population below an economic threshold, then use of an insecticide to control the pest and prevent economic loss is justified. In most cropping systems, insecticides are still the principal means of controlling pests once the economic threshold has been reached. They can be relatively cheap and are easy to apply, fast-acting, and in most instances can be relied on to control the pest(s). Because insecticides can be formulated as liquids, powders, aerosols, dusts, granules, baits, and slow-release forms, they are very versatile. Insecticides are classified in several ways, and it is important to be familiar with these classifications so that the choice of an insecticide is based on more than simply how well it controls the pest. When classified by method of application (site of encounter by insect), insecticides are referred to as stomach poisons (those that must be ingested), contact poisons, or fumigants. The most precise method of classifying insecticides is by their active ingredient (toxicant). According to this method the major classes of insecticides are the organophosphates, chlorinated hydrocarbons, carbamates, and pyrethroids. Others in this classification system include the biological (or microbials), botanicals, oils, and fumigants. Insecticides may be divided into two broad categories: (a) conventional or chemical and (b) biorational. In this guide we define conventional or chemical insecticides as those having a broad spectrum of activity and being more detrimental to natural enemies. In contrast, insecticides that is more selective because they are most effective against insects with certain feeding habits, at certain life stages, or within certain taxonomic groups, is referred to as "biorational" pesticides. These are also known as "least toxic" pesticides. Because the biorationals are generally less toxic and more selective, they are generally less harmful to natural enemies and the environment. Biorational insecticides include the microbial-based insecticides such as the Bacillus thuringiensis products, chemicals such as pheromones that modify insect behavior, insect growth regulators, and insecticidal soaps. The majority of insecticides fall into the chemical category because they are typically more effective and can usually be used to control several pests. This provides the economic justification needed for the research and development of such products. In contrast, the more specialized market of the biorationals makes their long-term economic return less favorable. Despite the advantages of conventional insecticides, the problems associated with their use have been well documented. These include the resurgence of pest populations after decimation of the natural enemies, development of insecticide-resistant populations, and negative impacts on nontarget organisms within and outside the crop system. One of the more serious problems is the development of resistance. Many insect pest species now possess resistance to some or several types of insecticides, and few chemical control options exist for these pests.
If all other integrated pest management tactics are unable to keep an insect pest population below an economic threshold, then use of an insecticide to control the pest and prevent economic loss is justified. In most cropping systems, insecticides are still the principal means of controlling pests once the economic threshold has been reached. They can be relatively cheap and are easy to apply, fast-acting, and in most instances can be relied on to control the pest(s). Because insecticides can be formulated as liquids, powders, aerosols, dusts, granules, baits, and slow-release forms, they are very versatile. To compare pesticide use patterns, the dose, formulation or percent active ingredient of the product, and the frequency of application must also be considered and are used to calculate the EIQ Field Use Rating. Pesticides with a lower EIQ Field Use Rating have a lower environmental impact. The EIQ concept and techniques are evolving, but this, or a smilar rating, will provide information for appropriate pest management decisions in the future.Natural enemies are generally more adversely affected by chemical insecticides than the target pest. Because predators and parasitoids must search for their prey, they generally are very mobile and spend a considerable amount of time moving across plant tissue. This increases the likelihood that they will contact the insecticide. When an insecticide is applied, ideally only the target pest(s) should be affected. The goal is to maximize pest mortality while minimizing harm to natural enemies.
The following factors, some of which are used when determining the EIQ, influence the impact of insecticide applications on natural enemies:
v Spectrum of activity. Insecticides toxic to most insects (broad-spectrum) will more adversely affect natural enemies than materials that are narrow-spectrum or selective for specific insect species or life stages. Most insecticides in use today have a broad spectrum of activity.
v Residual (half-life) activity of insecticide. Insecticides that remain toxic to pests for a long time and remain on the treated surface will have a similar effect on natural enemies.
v Coverage and formulation of insecticide. Full coverage sprays will generally have a greater impact on natural enemies than directed sprays, systemic, or bait formulations. Spot or edge treatments directed at localized pest infestations or to a specific plant surface most often occupied by the pest will be less detrimental than those applied to the entire field or plant.
v Dosage and frequency of application. Higher rates and repeated applications will have a more detrimental impact on natural enemies.
v Timing of application. Applying insecticides when natural enemies are not abundant or are less susceptible, such as when immature are encased in host eggs, can be helpful.
v Susceptibility of natural enemy to insecticide. Some natural enemies are inherently more resistant to insecticides than others, and some populations of natural enemies have been selected either naturally or through the efforts of researchers to possess higher levels of resistance. For example, strains of predaceous mites, rove beetles, lacewings, and species of parasitoids have been selected for increased levels of resistance to insecticides, thereby increasing the likelihood that some will survive insecticide treatments directed at pests. Some of these pesticide-tolerant strains are commercially available. Applications of some fungicides directed at controlling plant diseases can also reduce the incidence of fungal diseases of insects. In general, little can be done about this incompatibility except to use the fungicide only as needed.
In addition to killing natural enemies directly, insecticides may also have sub lethaleffects on insect behavior, reproductive capabilities, egg hatch, and rateof development, feeding rate, and life span. Fungicides and herbicides may also have lethal and sub lethal effects on natural enemies.
How can IPM help produce a profitable crop?
IPM is designed to help growers protect their crops while minimizing the input costs. IPM incorporates several pest management strategies to maintain crop profitability, minimize pest selection pressures, and minimize environmental impacts. Once a pest exceeds the economic threshold or reaches a threatening level, it is necessary to determine the best way to prevent unacceptable yield losses. Economic thresholds integrate the crop value and management costs with biological information on the relationship between pest injury and yield. The cost, safety, benefits, and risks of employing various management strategies are weighed and evaluated.
Cultural (agronomic practices)
- Selecting plant resistant varieties (Example: Growing resistant varieties of wheat for reducing severity of wheat stem sawfly.)
- Crop rotation (Example: Levels of Sclerotinia sclerotiorum, white mold, are reduced by crop rotation to non-susceptible hosts; common hosts of Sclerotinia in North Dakota are dry beans, sunflowers, soybeans, and canola.)
- Cultivation, tillage practices (Example: Cultivating row crops reduces herbicide applications.)
- Variation of planting or harvesting dates (Example: Delayed planting of sunflowers until late May or early June reduces sunflower stem weevil and sunflower beetle densities.)
- Plant spacing (Example: Narrower row spacing favors development of plant diseases due to environmental conditions within the crop canopy. More moisture on plant surfaces and higher relative humidity favors conditions for infection, such as with white mold in soybeans.)
- Fertilization level (Example: A crop with balanced fertility levels has greater capacity to resist disease organisms and a greater capacity to compete with weeds.)
- Sanitation (Example: Cleaning out storage areas or grain bins helps prevent infestations of stored grain insect pests.)
- Planting pest-free seed (Example: Planting disease-free seed or using seed treatments with a fungicide will help protect germinating seed and seedlings from seedling blight.)
- Planting trap crops (Example: A trap crop consists of a field margin planted to an early maturing sunflower that surrounds the remaining sunflower field area. The margins flower earlier than the remaining field interiors and attract the red sunflower seed weevil first. As a result, the trap crop concentrates the weevils in a smaller area reducing the cost of insecticide and time required for control.)
Mechanical
- Cultivation (Example: Clean tillage between field rotations decreases the establishment of new weeds, especially perennials.)
- Hand weeding (Example: Removing weeds by hand is only practical for use by the home gardener, organic grower or researcher, although sugar beet growers will often hire labor for hand weeding.)
- Exclusion using screens or barriers (Example: Banding trees with Tanglefoot to control cankerworms.)
- Trapping, suction devices, collecting machines (Example: Walk-through fly trap removes horn flies from range cattle; apple maggot trap in home orchard.)
Physical
- Heat (Example: Burning surface residues, soil pasteurization.)
- Cold (Example: Cold storage of potatoes to prevent storage rot.)
Biological
- Augmentation of natural enemies (Example: Simple sugar solutions can be used as artificial honeydew to promote aggregation of adult lady beetles in aphid infested crops.)
- Introduction of parasites or predators (Example: Releasing biocontrol agents (Aphthona flea beetles) to control noxious weeds (leafy spurge)).
- Propagation of diseases of pests (Example: Bacterial agents (Bacillus thuringiensis) for natural control of insect pests like Colorado potato beetle or European corn borer.)
Chemical
- Herbicides, Insecticides, Fungicides
- Miticides, Nematicides, Rodenticides, Avicides (blackbirds)
- Biological pesticides (for example, insect molting inhibitors)
- Defoliants
- Desiccants
Conclusion
Area-wide pest management technologies will take on new appearances as the drive to eliminate and/or greatly reduce the use of chemical pesticides increases. The use of IPM has the most potential for successfully displacing certain pesticides. Here reported that possibility of developing proper cultural, mechanical, genetical and chemicals for effective removal of insect and pest and discuss ways in which such components could be used successfully in an integrated pest management system. If such an approach were developed, it could be utilized with other alternative methods, thereby providing a safe, ecologically sound means of controlling insect pests without damaging the agricultural economy.
References
Hoffmann, M.P. and Frodsham, A.C. (1993) Natural Enemies of Vegetable Insect Pests. Cooperative Extension, Cornell University, Ithaca, NY. 63 pp.
Internet Source
Comments
Post a Comment