Avoidable obstacles to colonization in classical biological control of insects

Abstract

Most classical biological control attempts worldwide against pest insects have failed to meet the objective of solving the pest problems permanently. The dominant cause was failure by introduced agents to colonize. Most failures to colonize can be attributed to procedures that were detrimental to the numbers or health or the target-finding or field survival abilities of newly released agents. Administrative reactions to the low success rate, poor cost/benefit data, and overselling of the method were basically responsible for those procedures. As ways of avoiding such procedures exist, it is feasible to make colonization a probability. This should substantially improve the chances of control being successful, enable past failures to be reopened, and expand the scope of classical biological control.