Conservation and evaluation of natural enemies in IPM systems for Bemisia tabaci

Abstract

Conservation biological control emphasizes the preservation and enhancement of natural enemies and is the cornerstone of all approaches to biological control. This review critically examines recent and current research efforts in conservation biological control by predators and parasitoids of Bemisia tabaci worldwide. A large number of natural enemy species have been identified from many agricultural systems. Further research has demonstrated that these natural enemies may act along with other mortality agents to inflict high levels of mortality on populations of B. tabaci. Less effort has been placed on determining the factors constraining or potentially enhancing biological control. The widespread use of broad-spectrum insecticides in many crops has severely hampered the contribution of predators and parasitoids to pest suppression. However, the arsenal of selective insecticides has grown in the past decade and their increased usage may permit the true integration of biological control into IPM systems. The effects of species interactions (e.g., intraguild predation) and host-plant attributes on disruption of biological control are poorly understood in most systems. Research in the area of habitat manipulation and enhancement is minimal. Very little research has addressed the evaluation of natural enemy effects on B. tabaci population dynamics in any system. As a result our ability to predict and exploit these effects for pest suppression are limited. Problems in estimating and interpreting parasitism are highlighted. Recent life table studies of B. tabaci in Arizona cotton are summarized to demonstrate how integration of natural enemies with use of selective insecticides resulted in the development of an efficient pest management system. Avenues for future research are discussed that may enhance the use of conservation biological control as a key tactic in IPM of B. tabaci.