What is IPM?
Integrated Pest Management (IPM) is an ecosystem-based approach that prioritizes long-term pest prevention through methods like biological control, habitat modification, and using resistant plant varieties. Pesticides are used only when necessary, after monitoring determines they are needed, and applications are targeted to minimize risks to humans, beneficial species, and the environment. Effective IPM starts with correct pest identification to ensure management methods are both efficient and safe.
These IPM principles and practices combined to create IPM programs. While each situation is different, six major components are common to all IPM plans:
- Pest identification
- Monitoring and assessing pest numbers and damage
- Guidelines for when management action is needed
- Preventing pest problems
- Using a combination of biological, cultural, physical/mechanical and chemical management tools
- Assessing the effect of pest management after action is taken
Orange County Specialty Pages
What is a pest?
Pests are organisms that harm plants, structures, or health by causing damage, spreading disease, or becoming nuisances. They can be weeds, animals (like birds or rodents), insects, nematodes, pathogens (such as bacteria or fungi), or any unwanted organism that negatively affects water quality, wildlife, or ecosystems.
Pest identification
Pest identification is the first step in implementing Integrated Pest Management (IPM) in your garden. IPM programs work to monitor for pests and identify them accurately, so that appropriate control decisions can be made in conjunction with action thresholds. Both identification and monitoring remove the possibility that pesticides will be used when they are not really needed or that the wrong kind of pesticide will be used.
Information about pest identification and management is available at UC IPM(select Pests in gardens and landscapes). If you know the name of your pest, use the Pest Notes Library which contains information on pest identification, biology and habitat, life cycle, damage and impact, plus colorful photographs or illustrations to assist in identification. For information on pest management techniques and identification for a broad range of California pests, go to home, garden, turf, and landscape pests. If you see damage to plants or the ground, animal tracks, or droppings, use the Wildlife Pest Identification Tool to identify what animal is causing your problem.
The UC Master Gardener hotline can help you identify pests. Retail nursery and garden centers are also among the top sources of pest management information for home gardeners.
Exotic and invasive pests also threaten California’s ecosystems, agriculture, structures, and gardens. These organisms are introduced outside their natural range—usually by accident—and may become pests. Prevention is the most cost-effective way to manage invasive species, but when it fails, pesticides may be required for control or eradication. Home gardeners can help in this effort by identifying new invasive species in Orange County. Report invasive species to your local UC Cooperative Extension office or Agricultural Commissioner, and follow instructions during control efforts.
Monitoring and assessing pest numbers and damage
Monitoring involves regularly inspecting your garden to determine which pests are present, how many there are, and what kind of damage they may have caused. Accurate pest identification is crucial for assessing the potential threat and deciding on an appropriate management approach. By combining the results of monitoring with knowledge of the pest’s biology and environmental conditions, you can determine whether the pest poses a serious problem or can be tolerated. If control is necessary, this information will guide you in choosing the most effective control methods and the optimal timing for their application.
IPM describes the action threshold as the point at which pest populations or damage levels warrant intervention. This threshold depends on factors such as the cost of control, the value of the plants, and potential environmental impacts. A small number of pest insects and minor damage are often unavoidable and can usually be tolerated.
IPM emphasizes setting action thresholds before taking any control measures. Seeing a single pest does not necessarily mean action is needed. Control should only occur when pest levels pose a real threat, helping to prevent unnecessary or ineffective pesticide use. When management action should be taken (when a threshold is exceeded) is determined by the cost of the action, the value of the plant, and the impact on the environment.
Gardeners who regularly monitor their plants, maintain detailed records, and evaluate outcomes over time can develop specific thresholds that guide future decisions. Not all insects, weeds, or other organisms require control—many are harmless or even beneficial. Accurate identification and consistent monitoring are essential to ensure that control methods are appropriate, timely, and environmentally responsible.
Guidelines for when management action is needed
When the threshold is met, choose guidelines that emphasize long-term prevention or suppression of pest problems while minimizing impacts on human health, the environment, and non-target organisms. Preferred pest management methods involve:
- Promoting natural biological control
- Using alternative plant species or varieties that are resistant to pests
- Choosing pesticides that are less toxic to humans and non-target organisms
- Adjusting cultivation, pruning, fertilization, or irrigation practices to reduce pest issues
- Altering the habitat to make it less suitable for pest development
Once monitoring, identification, and action thresholds indicate that pest control is required, and preventive methods are no longer effective or available, the next step is to evaluate the proper control method both for effectiveness and risk. Effective, less risky pest controls are chosen first, including highly targeted chemicals, such as pheromones to disrupt pest mating, or mechanical control, such as trapping or weeding.
If further monitoring, identifications, and action thresholds indicate that less risky controls are not working, then additional pest control methods can be used, such as targeted spraying of pesticides. Broadcast spraying of non-specific pesticides is a last resort. Pesticides selected are those that are least toxic and most specific to the target pest. Always read the information on the label.
Preventing pest problems
The most effective way to manage pests and diseases in a vegetable garden is to prevent them in the first place. Because healthy soil is fundamental to healthy plants, any successful IPM program prioritizes soil care. While plants produce their own energy through photosynthesis, they rely heavily on soil for essential needs such as water, nutrients, and stability. It is important to provide optimal growing conditions by making sure plants get the right amount of sunlight, water, and nutrients and avoiding over-fertilizing, especially with nitrogen, which can encourage lush growth that attracts pests. Other preventative actions:
- Practice smart planning by adjusting the planting schedule of susceptible crops to avoid peak pest activity.
- Choose plant varieties that are resistant or tolerant to common pests and diseases. These are often indicated by letter codes on seed packets or in seed catalogs.
- Ensure containers and potting soil are clean and free from pathogens, weed seeds, or insects before planting.
- Think about how weather or seasonal changes may affect pest populations.
- Consider whether pest problems are being caused by certain gardening practices that can be adjusted.
Prevention is always more effective—and less damaging—than reacting after a problem occurs. To stay ahead of pests in your area, check out the Seasonal Landscape IPM Checklist.
Using a combination of biological, cultural, physical/mechanical and chemical management tools
Management strategies for managing pests in home gardens are more effective if they are used in combination. They are grouped into the following four categories:
Biological Control: Most gardens contain far more good bugs, or beneficial insects, than pest insects. Beneficial insects and other organisms that kill pests are called natural enemies. The use of natural enemies—predators, parasites, pathogens, and competitors—controls pests and their damage. In any pest management program, it is important to encourage these natural enemies by avoiding pesticides that kill them. You can also encourage beneficial insects by choosing plants that provide them with pollen, nectar, and shelter and by keeping ants out of pest-infested plants. Learn to identify beneficial insects, both in their adult forms and immature (larval) stages.
Cultural Control: By using cultural control, the home gardener can reduce pest establishment, reproduction, dispersal, and survival. These practices–including use of resistant varieties, mulching, weeding, using proper irrigation techniques, and pruning–produce more consistent, long-term pest management. An example: changing irrigation practices, since too much water can increase root disease and weeds.
Mechanical and Physical Control: Mechanical controls entail trapping, disrupting pests’ lifecycles by tilling the soil, installing or repairing proper irrigation, destroying weed beds that harbor pests, and eliminating standing water. One example is using rodent traps. Physical control involves making the environment unsuitable for the pest’s survival: preventing entry with the use of barriers, manually removing pests by handpicking, vacuuming, or trapping pests. An example is installing netting to restrict insects.
Guidelines for using mechanical and physical control:
- Learn to identify beneficials and pests.
- Keep the garden clean by removing sources of food, water, and hiding places for pests.
- Learn to accept some damage in the garden—perfection is not required.
- Prevent infestation by using native plants.
- Fertilize and water appropriately. Over-fertilization may cause excessive growth, weakening of the plant and attraction of pests.
- Maintain proper plant spacing to encourage good air circulation.
- Enrich the soil–healthy soil promotes healthy plants. Add compost to the soil to increase fertility and improve soil structure. Use mulch on top of soil to suppress weeds and retain moisture.
- Encourage natural predators by providing food, water, shelter for beneficial insects, birds, and lizards.
Chemical Control: In IPM, pesticides are applied only when necessary and when combined with other methods for long-term pest control. Pesticides are chosen and used in ways that reduce potential risks to humans, non-target species, and the environment.
- Begin with mechanical controls that are less toxic, such as removing pests with a hose, manually collecting slugs and snails, or using traps and barriers.
- If pesticides are needed, select those that are considered less toxic, including insecticidal soap, horticultural oil, Neem oil, Bacillus thuringiensis (Bt) for caterpillars, pyrethrins, or Spinosad.
- Maintain an inventory of chemical products in your household and update it regularly.
- Dispose of pesticides, expired materials and those with unreadable labels or damaged containers according to recommended guidelines.
- Use pesticides with care and only when other options are insufficient. Follow all label instructions precisely.
- Select pesticides suited to the specific pest and apply them when there is no risk to beneficial insects or mammals.
To learn about known hazards of specific pesticides to public and environmental health, check out UC IPM's Pesticide Active Ingredients Database
After action is taken, assess the effect of pest management
Integrated pest management uses scientific methods to manage the whole ecosystem in such a way as to minimize or eliminate pest impact. Thresholds set criteria for decision-making, while biological, cultural, mechanical, and chemical controls are re-evaluated as needed based on observations and changing conditions.
- Monitor your garden regularly—at different times of day
- Inspect stems, leaves and blossoms.
- Keep a garden notebook to record pest sightings, noting plant host and numbers.
Regular monitoring and keeping records help assess effectiveness and guide management strategy adjustments.