The integration, or the appropriate use of all available tactics for preventing or managing pests, is what gives IPM its name. The tactics or methods fit into one or more of the following categories: cultural, mechanical/physical, biological, genetic, chemical, and regulatory. Some examples within each category are described below. A key component of IPM is to select methods that are most effective in preventing or controlling the pest yet the least harmful to people and the environment.
Cultural Controls are practices that disrupt the environment to deprive pests of a comfortable habitat or prevent their spread. Cultivation and sanitation are two examples of cultural control. In agriculture, cultivation using plows, disks, cultivators, and bed conditioners, is one of the most important ways to destroy weeds or control their growth. Cultivation may also disrupt soil conditions suitable for the survival of some microorganisms and insects. Sanitation involves eliminating the necessities important to a pest’s survival, such as food, water or shelter. It includes such practices as destroying diseased plant material or crop residues, and keeping field borders or surrounding areas free of pests and pest breeding sites. Animal manure management is an effective sanitation practice used to prevent or reduce fly problems in poultry and livestock operations. Mosquitoes can be controlled by draining standing water. Closed garbage containers and frequent garbage pickup eliminate food sources for flies, cockroaches, wasps, and rodents. Mowing, irrigation, aeration, and fertilization are all important ways of producing healthy turf and preventing pest buildup and damage.
Mechanical and physical controls can kill a pest directly or make its environment unsuitable. Rodent traps are examples of mechanical control. Traps can be mechanical devices or sticky surfaces, some with pheromones incorporated to increase trapping efficiency of specific types (species) of insects. Physical controls include steam soil sterilization for soil-borne microorganisms. Physical barriers and exclusion includes the use of mulches for weed management, deer fences, screens to keep insects out, and netting to exclude birds from fruit trees. Another example is sealing cracks, crevices, and other small openings in buildings to exclude insects, rodents, bats, birds, and squirrels. A band of sticky material painted around tree trunks (see image on right) prevents crawling insects from reaching the tree’s leaves.
Pests living in enclosed areas may sometimes be suppressed by altering physical and environmental conditions, such as water, air movement, temperature, light, and humidity. Refrigeration, for example, protects stored food products, furs, and other items from insect pests. Lowered temperatures kill the insects, cause them to stop feeding, and prevent egg hatch or development. Lowering the humidity of stored grains and other food products reduces damage from molds and some insects. And, increasing air movement in greenhouses often helps to prevent fungal diseases from developing on plants (another example is the use of fans to move the air above golf course greens).
Biological Control is the use of natural enemies (biological control agents) to control pests and their damage. It involves the conserving or releasing of predators, parasites, pathogens, and/or competitors to prevent the rise of certain pests. Examples include beneficial mites that feed on mite pests in orchards, the parasitic nematodes that kill root-feeding grubs, and tiny wasps, known by their scientific name, Encarsia formosa, that parasitize the greenhouse whitefly. Effective biological control relies upon the maintenance, or conservation, of healthy populations of native natural enemies. This could mean establishing areas of flowering plants (refuges) or groundcovers to ensure a supply of nectar, alternative hosts, and shelter for adult insects. This method also requires careful selection and use of pesticides that are less toxic to natural enemies. Or, if recommended and effective, applicators should apply pesticides at lower-than-label rates to lessen the impact on natural enemies.
Purchasing and releasing predators and parasites of pests can be effective in reducing pest populations especially in greenhouses or other enclosed structures. Because this method usually does not yield long term results in fields or orchards, large numbers of natural enemies must be mass released periodically. When successful, these biocontrol agents become established and lower target pest populations for long periods.
Genetic Control involves the “built-in” or inheritable traits of plants and animals to resist, or tolerate, specific pest problems. Certain plant varieties are naturally resistant to insects, pathogens, or nematodes. Some are bred for these traits. Likewise, certain livestock breeds are selected for physical characteristics that prevent attack by some pests or provide physiological resistance to disease or parasitic organisms. Genetic control has been widely used in the past and is envisioned to be an effective tool in the future, especially when combined with new gene manipulation techniques. Some crop plants are genetically modified through molecular techniques to add a small amount of genetic material from other organisms. The incorporated genetic traits provide protection from pests (e.g., Bt, [Bacillus thuringiensis], crops produce a protein that kills caterpillars), tolerance to herbicides, or an improvement in quality.
Pesticides, or chemical controls, are an important tool for many IPM programs and may often be the only known control method for a given pest. Pesticides are naturally derived (those used in organic production), synthetic, or a combination of the two. The major benefits associated with the use of pesticides are their effectiveness, the speed and ease of controlling pests, and their reasonable cost compared with other control options. Use pesticides judiciously, with proper timing for the best targeted control, and according to all written instructions on the product label to protect beneficial organisms including pollinators and the environment. The pesticides must be labeled for use on the intended crop or site. Also select according to effectiveness, previous use patterns, and the potential for resistance. Pesticides are most effective when used in conjunction with other tactics for meaningful control. Other, lesser known, pesticides that are registered as such by the U.S. EPA include repellents that can reduce damage from vertebrates, insects, or disease-vectoring organisms and pheromones. Pheromones are natural insect scents that elicit a response from insects in very low concentrations. Sometimes a manufactured “copy” of the pheromone that a female insect emits to attract mates can be used to confuse males and prevent mating. These sex pheromones are highly species-specific.
Regulatory Control is deployed for pest problems that cannot be controlled successfully at a local level or by individuals. These problems are caused by pests that seriously endanger public health or are likely to cause widespread damage to agricultural crops or animals, forests, or ornamental plants. Quarantine or eradication programs directed by governmental agencies according to federal and state laws target the introduction and spread of such pests. Quarantine is a pest control process designed to prevent entry of certain pests into areas where that pest does not exist. Quarantine also prevents movement of designated pests within a state. Identified items being shipped from a quarantine area must be treated to destroy pests before shipment. Nursery stock, plant cuttings, seed shipments, and budding and grafting material are also regulated to prevent the spread of pests. Mosquito abatement is an important pest control function undertaken to protect public health. Mosquito abatement laws allow state agencies to drain or treat standing water that provides breeding sites for mosquitoes. Efforts to quarantine new populations, and slow the spread of new pests are frequently undervalued but provide the highest return of investment for management while avoiding disruptions to the currently used IPM strategies.