- Plants: Knowledge of the associated plant material under one's care is a primary element, including identification of the plants, as well as the components of their optimal growing environment, such as hardiness zones, soil pH, and water requirements.
- Inherent pests: Virtually every plant species has at least one potentially harmful pest associated with it. It is important to know these pests and their life cycles.
- Beneficial organisms: Nature is a system of checks and balances. Most everything in nature is a potential meal for something else. IPM practitioners must know the insects and mites that feed on potential pests and help to preserve them with sound management techniques.
- Incidentals: The vast majority (about 93%) of insect species are not pests. It is important to be able to determine when the presence of insects on plant material does not warrant any intervention.
This is the backbone of any IPM program. If one is not actively and regularly monitoring for pest activity, then IPM is not truly being implemented. Many University Extension systems provide growing degree day information (GDD) (see UMass Extension's Landscape Message), updates on recent pest activity, and reports on weather conditions to their clients. Monitoring techniques include visual inspection as well as the use of specialized traps.
Knowing the Economic/Aesthetic Injury Level:
In traditional agriculture, the relationship between the size of a pest population during the growing season and the potential severity of crop loss at harvest has long been understood. This is known, in its simplest terms, as the economic threshold level, and is the point at which the potential loss in dollars at harvest time equals the cost of managing a pest at some point during the growing season. In contrast, determining the "potential loss" of ornamental plants is a much more complex calculation, and is subject to the individual client's expectations and desires. Since the "value" of ornamental plants is based primarily on appearance, it is probably safe to speculate that the need to implement pest management occurs long before the long-term health of the plant is affected. In a nursery situation, the economic threshold is attained when a pest presence devalues the wholesale/resale potential of those plants. Oftentimes, a minor amount of insect injury that can significantly reduce a plant's value at the garden center is in no way detrimental to the plant's health.
Knowing the Correct Treatment:
Today, pest management decisions consist of much more than identifying the pest and applying a chemical pesticide. The selection of pest management materials currently available is extensive, but these diverse options require a broad understanding of how these new materials work and when they can be best used to manage pests.
Knowing the Correct Timing of Management Strategies:
When chemical pesticides were the norm for pest management, applicators could, for many pests, wait until within 24 hours of reaching the economic threshold and then apply an effective chemical that achieved almost instant results This is still the case for many of the chemicals we have today. However the new bio-rational compounds require greater thought and more carefully timed implementation for maximum effectiveness.
By law, all pesticide applicators must maintain timely and accurate records of their activities. In an IPM program, one should maintain additional records that will provide information for making the best pest management decisions in the future. Important variables to consider are weather conditions, additional stresses that the plant may be experiencing, planting history, irrigation practices, life stage of the target pest, and pH of the spray tank water. This may be cumbersome and time consuming, but can be of great value for future decision-making.
IPM can be thought of as a toolbox. The most important tool in that toolbox is the practitioner's knowledge that is gained through continued experience and education. Evaluating the sucess or failure of an attempt at pest managment is an invaluable tool for the future.
Written by: Robert Childs