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Integrated pest management

Approach for economic control of pests

  • 18 min read
  • 4 chapters
  • 1 lab on Lably

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"IPM is the careful consideration of all available pest control techniques and subsequent integration of appropriate measures that discourage the development of pest populations. It combines biological, chemical, physical and crop specific (cultural) management strategies and practices to grow healthy crops and minimize the use of pesticides, reducing or minimizing risks posed by pesticides to human health and the environment for sustainable pest management."

First developed for agricultural pest management, IPM programs are also used to deal with diseases, weeds, insects and animal pests at residential and commercial locations, lawns and turf, community gardens and homes. IPM is a safer pest control framework than reliance on chemical pesticides, mitigating risks such as insecticide-induced resurgence, pesticide resistance and (especially food) crop residues. Predictive models are useful tools in the implementation of IPM programs.

Principles

Integrated pest management relies on understanding the structure and functions of an ecosystem. Multiple techniques are dynamically combined and adjusted in response to changes in environmental, economic, and social conditions. Programs developed in one region may need to be adapted before they can be successfully adopted in another region, to address differences in biological variation in pest ecosystems, environmental conditions, scale and capacity of response, regulatory environment, and cultural context.

Prevention

Cultural practices—The first line of defense for a garden or farm is to select varieties suited to local growing conditions such as resistant varieties and maintain healthy crops. Cultural practices may include techniques such as crop rotation and intercropping to promote healthy growing conditions.

Sanitation practices are essential. When dealing with plants, one can quarantine or remove diseased plants and take preventive measures such as cleaning of equipment (e.g. pruning shears) and selective disposal of debris to prevent spread of infections and pests. Sanitation practices that remove sources of food, water, and shelter are essential to protect homes from pests. Schools, health care facilities, food services and other businesses also require careful and ongoing sanitation practices.

If pests reach an unacceptable level, mechanical control methods can be used, such as simple hand-picking to remove insects, water spraying, vacuuming, barriers, and traps. Tillage can be detrimental to soil structure, but it is sometimes used in coordination with the life cycles of pests.

Monitoring

Acceptable pest levels—IPM holds that wiping out an entire pest population is often impossible, and the attempt can be expensive and unsafe. Emphasis is placed on control, not eradication.

IPM programs identify acceptable pest levels or action thresholds based on estimated economic injury, and apply controls if those thresholds are exceeded. An economic injury level is the pest population level at which damage to a crop will be greater than the cost of treating the pest. An economic threshold is the population size at which action must be taken to prevent the pest population from reaching the economic injury level. Thresholds are pest and site specific, meaning that it may be acceptable to have a weed such at one site, but not at another site. For example, white clover may be acceptable on the sides of a tee box on a golf course, but not in the fairway where it could interfere with play.

Allowing a pest population to survive at a reasonable threshold reduces selection pressure. This lowers the rate at which a pest develops resistance to a control, because if almost all pests are killed then those that have resistance will provide the genetic basis of the future population. Retaining a significant number of unresistant specimens dilutes the prevalence of any resistant genes that appear. Similarly, the repeated use of a single class of controls will create pest populations that are more resistant to that class, whereas alternating among classes helps prevent this.

Regular observation is critically important for inspection, pest identification and ongoing monitoring. Scouting and sampling techniques such as visual inspection, insect and spore traps, and other methods are used to monitor pest levels. Automated systems using AI are also being developed for monitoring, but face obstacles in terms of their cost, effectiveness, mobility, and scalability to use in the field.

Record-keeping is essential, as is a thorough knowledge of target pest behavior and reproductive cycles. Insects are cold-blooded, so their physical development is dependent on area temperatures. Many insects have had their development cycles modeled in terms of degree-days. For example, degree-day models have been developed for invasive pests such as the fall armyworm (Spodoptera frugiperda), whose egg, larval and pupal development rates increase linearly with temperature over roughly 18–30 °C, allowing prediction of generation timing and the geographic limits of the pest's establishment. The degree days of an environment determines the optimal time for a specific insect outbreak. Plant pathogens follow similar patterns of response to weather and season. However, these are increasingly disrupted by climate change.

Biological controls

Natural biological processes and materials can be used as biological control agents (BCAs), with acceptable environmental impact, often at low cost. The main approach is to promote beneficial insects or other predators that eat or parasitize target pests. Augmentative biocontrol involves increasing natural enemies and pathogens such as predators, parasitoids or microbes, so that they can fight pests and diseases in an area on a timely basis. Conservation biocontrol uses farming practices to better support existing populations of natural enemies already in the environment, such as ladybugs, so that they increase. Classical biological control or importation biocontrol introduces new populations of natural enemies or pathogens which may not be native to an area.

Beneficial fungi and bacteria produce bioactive compounds that can protect soil and crops from bacterial, fungal, and nematode diseases, reducing the need for fungicides. Beneficial bacteria can improve plant growth and control disease without harming the environment.

Genetic pest control introduces genetically modified organisms to reduce pest populations. For example, the sterile insect technique (SIT) releases sterilized males of a given species so that matings will be infertile. By targeting the reproductive capacity of the target pest, population size is reduced to non-critical levels. Other genetic approaches manipulate sex determination genes, increase the occurrence of dominant lethal genes, or skew sex ratios in the population. Genetic control programs' success depends on the dispersal rate, longevity, and mating success of introduced pests.

Chemical controls

Synthetic pesticides, which include insecticides, fungicides, and herbicides, have been shown to have a wide range of negative effects on non-target as well as target organisms. Responsible use of pesticides involves using them only as required and often only at specific times in a pest's life cycle.

Biological insecticides, derived from naturally occurring microorganisms (e.g.—Bt, entomopathogenic fungi and entomopathogenic nematodes), also fall in the category of chemical controls. Many newer pesticides are derived from plants or naturally occurring substances (e.g.—nicotine, pyrethrum and insect juvenile hormone analogues), but the toxophore or active component may be altered to provide increased biological activity or stability. Chemical controls also include horticultural oils.

Applications of pesticides must reach their intended targets and avoid harming nontarget species. The application technique must be matched to the crop, the pest, and the pesticide. For example, the use of low-volume spray equipment can reduce overall pesticide use and operational costs. Taking all recommended precautions is critical. IPM is an alternative to calendar-based pest control approaches which are becoming less effective, in part due to climate change.

IPM practices known as resistance management are essential in preventing and slowing the development of resistance to chemical controls, including biological insecticides.

Process

Using these components, integrated pest management becomes an ongoing process that can be thought of in terms of six repeatable steps:

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