Forests are one of the national assets of every country and any human intervention will cause pest outbreaks. Forest pest management is different from other ecosystems because it is difficult to understand the relationship between complexity and forest ecosystem sustainability. Natural enemies that are more specific in their choice of host may be suitable for release in biocontrol programms because they feed on a limited range of hosts and so could not have destructive effects on non-target organisms. So, the suitable selection is necessary to decrease the risk of effects on non-target populations. Also, due to the fragility of forest ecosystems, it is necessary to identify, evaluate and protect native natural enemies.