Suppression tactics are used when indicators of pest activity call for action to reduce the risk of damage. Choice and timing of using these tactics are based on the pest biology and behavior, limitations placed on the area where the pest is occurring, tolerance for injury, economics, and impacts of the control measures themselves. Suppression tactics include cultural practices, physical barriers, biological controls, and pesticide applications described briefly below. Remember to assess the success or failure of any corrective measures taken!
Cultural Controls are those that disrupt the environment of the pest, and/or prevent its movement. Plowing, crop rotation, removal of infected plant material, cleaning of greenhouse and tillage equipment, and effective manure management are all cultural practices that are employed to deprive pests of a comfortable habitat or prevent their spread. Manage irrigation schedules to avoid long periods of high relative humidity. Wet, highly humid conditions encourage disease pests to develop. When possible only irrigate the root system and not the foliage.
Physical Barriers such as netting over small fruits, and screening in greenhouses, can prevent insects that cause crop loss; mulch can inhibit weed germination beneath desirable plants. Physical barriers are important in termite, house fly, and vertebrate control. Add netting, grid wires, spikes, or other barriers to discourage pest birds.
Biological Controls involves the conserving or releasing of natural enemies (biological control agents) to prevent the rise of certain pests. Examples of biological control agents are beneficial mites that feed on mite pests in orchards, the parasitic nematodes that kill harmful soil grubs and Encarsia formosa, a wasp that parasitizes the greenhouse whitefly. Many biological control agents are commercially available. Purchasing and releasing predators and parasites of pests (if legal, approved and available), can be effective in reducing pest populations especially in greenhouses or other enclosed structures. To conserve these natural enemies of the pest, develop refuges by establishing areas of flowering plants and shrubs to supply nectar, alternative hosts, and shelter.
Pesticides are an important tool for many IPM programs. They are most effective when used in conjunction with other tactics for meaningful control. 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 efficacy, previous use patterns, and the potential for resistance.
Other 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.
Follow up! After corrective measures are taken, assess the success or failure of the suppression tactic. Monitoring will determine if additional or different suppression tactics are needed, as well as informing future prevention and avoidance activities.
- What is IPM?
- Why Practice IPM?
- Pest Identification
- The PAMS Approach
- IPM Resources
- IPM Quiz