It is a man-made term and has no ecological validity.
Pests come in many different types and shapes.
As you have probably encountered, pests can cause tremendous problems. When we have a pest problem, we have to take some action to solve or control the problem. IPM or Integrated Pest Management has been developed extensively for agricultural systems. However, IPM is in its infancy for landscape management. Simply stated, IPM is an ecological approach to preventing or reducing unacceptable pest presence or damage .