Integrated Pest Management, more often referred to as IPM, is the concept of using multiple complimentary management strategies to maintain an insect pest population below an economic injury level or threshold (i.e., population that causes observable yield loss). The use of IPM in production systems is recommended because the use of multiple management strategies reduces the selection pressure exerted by each singular strategy. This, in turn, reduces the risk of having a resistant insect pest emerge. The six components that must be considered when developing an IPM program include:
- Pest Identification
- Pest Monitoring and Record Keeping
- Management Recommendations
- Prevention and Exclusion
- Utilizing Multiple Management Strategies
- Reassessing the Effect of Pest Management
When an IPM program is developed and utilized for pest management, it can work to minimize repeated use of pesticides with a single mode of action, eliminate prophylactic pesticide applications, and prevent low-rate applications. All three of these examples contribute to resistant pest populations because they increase the selection pressure. When pesticides no longer reduce pest populations, the quick response is to start using a pesticide with a different active ingredient or mode of action. However, this approach can lead to further issues and is often referred to as the “pesticide treadmill.” A better approach is to incorporate the use of multiple management strategies to reduce selection pressure for pesticides and improve their longevity.
Pest Identication, Monitoring and Record Keeping
In all cases, an IPM program is solely dependent on the persistent monitoring and scouting of production fields. A producer should know or become familiar with the historic trends and environmental composition of their fields and make management decisions based on that knowledge. One of the first steps in monitoring pest populations is being familiar with what pests may be present and the best methods to employ for scouting. For belowground pests, bait stations and soil samples can be used. For mobile aboveground pests, sweep net sampling, pan traps, or yellow stickycards can be effective. For slow moving pests, such as caterpillars, a beat sheet or bucket can be used to knock plants against to dislodge insects so that they can be counted. Key factors of a scouting program include:
- What pests are present and the level of infestation.
- Growth stage of the pest and crop.
- Presence of natural enemies and/or diseases of the pest.
- If the pest populations are increasing or decreasing.
- General physical conditions of the field including soil and surrounding environment.
- Recording all of this information in a notebook that can be referenced at a later date.
When pest populations are observed in the field, they should be monitored and compared to existing economic thresholds. An economic threshold is the number of pests that warrant a management action to occur. They are established to prevent pest populations from reaching the economic injury level. The economic injury level is the population of a pest that will begin to cause observable economic loss. Management recommendations that are provided through SDSU Extension give threshold information along with options for the management strategies that can be used.
Prevention and Exclusion Through the Use of Multiple Management Strategies
As mentioned previously, an observed pest population should be closely monitored to avoid economic injury. However, when an IPM program is implemented, sometimes pest populations can be kept below threshold levels without the use of pesticides. The multiple management strategies that should be incorporated in an IPM program include:
- Biological control: encourage the presence of natural predators to remove pest populations
- Cultural management: these practices can include host plant resistance, tillage, cover crops, crop rotation, etc.
- Mechanical or physical management: using barriers such as mulch or trap crops to prevent pest movement into desired crop
- Chemical management: when all else fails, use pesticides to reduce pest populations
When a management action has been taken, it is important to then re-evaluate the field to ensure that the management strategy was successful. This should be done within 1-3 days of application of a pesticide (specifically an insecticide) to monitor for effectiveness and for potential resistance issues.