Part 2, Section 1: Pest Management
Pest Management
Activities Involved in an IPM Program
Assessing the success of a management alternative
Once a management alternative has been implemented, it is a sound practice to evaluate its performance. If possible, leave one area untreated and examine it to determine crop yield in the absence of the activity. Without this area, there is no way of knowing, for some insects, if an action was economically beneficial. For instance, if no insects were present in a field and a management strategy was implemented based on an improper assessment of the problem, then the absence of an untreated area would make it appear that the management action was successful.
Although it is usually easier to select a field margin for the untreated area, this is a questionable practice because many insects tend to aggregate along field margins. Damage along the margin is much greater than it is deeper in the field. The best technique for assessing the benefits of a management strategy is to randomly select two or three small areas in the field to leave untreated. For pesticides in row crops, simply turn off the applicators on part of the rows to leave untreated areas.
The only situation where leaving untreated areas in a field is not a good way to measure the effectiveness of a management strategy is in fields infested with potato leafhopper. Potato leafhopper adults will migrate from treated areas into untreated areas, resulting in increased damage and causing insecticide application benefits to be overestimated.
By evaluating the success of each possible management strategy, you can determine the most effective approach to managing a pest or combination of pests. Evaluation also can help determine which management strategies are most effective under various conditions.