It is important to point out the impact of using broad-spectrum insecticides. While most users understand the general concerns of pollution and human safety surrounding these chemicals, most have little idea of the impact these materials have on desirable nontarget organisms. The best understood of the impacts are resurgence and secondary pest outbreaks.
Resurgence of a target pest occurs when a broad-spectrum insecticide is applied before it is necessary. This often results in a rapid rebounding of the pest to levels higher than at the time of application due to the elimination of the pest's predators or parasites. This occurs often enough to warrant seeking other solutions. At least wait to see if a pesticide application is really necessary.
Secondary pest outbreaks occur when broad-spectrum insecticides are applied to control one target pest, and they eliminate parasites and predators of other pests as well.