Commercial uses often demand intensive monitoring or scouting of the cropping system. Augmentive releases are meant to reduce populations at points in time. Releases at low pest densities are more effective than attempts to reduce high pest densities. Timing of the release of natural enemies is critical since most require some time to affect the pest population. Multiple releases may also be necessary to maintain pest suppression.
Biological control using parasites is generally pest-specific.
In cases where natural enemies are unavailable for augmentation, use of a selected pesticide that spares other natural enemies may be necessary. These factors are often unpredictable and result in erratic results from releases. Release of appropriate natural enemies in greenhouses and interiorscapes often provide more consistentresults. Insecticide residues on the crop or site, or insecticide drift from adjacent areas, can remain toxic to natural enemies long after the pesticide was applied. Residues should be mitigated prior to releases.