Journal of Insect Science (2003) 3 (33), p. 16 (Naranjo et al.)

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Steven E. Naranjo and Peter C. Ellsworth (2003)
The role of conservation in biological control of Bemisia tabaci: A life table approach
Journal of Insect Science 3 (33), 16-16
XIII International Entomophagous Insects Workshop - July 27-31, 2003, Tucson, Arizona, U.S.A.
Abstract: Within agricultural systems there are multiple abiotic and biotic mortality forces acting on pest insect populations. These forces may be naturally-occurring, as in the case indigenous natural enemies, or man-made as exemplified by insecticides or cultural manipulations. Estimating the contribution and effect of each mortality factor may be difficult because of interactions between factors resulting in mortalities that may be either replaceable or indispensable. From the perspective of conservation biological control, estimating mortality caused by extant natural enemies within the context of other mortality agents is important to understanding the base contribution of biological control to pest suppression, and to evaluating the benefits of manipulating the habitat and other system inputs. Field studies examined the role of natural enemy conservation in cotton within the context of alternative management strategies for Bemisia tabaci (Gennadius) based on selective and non-selective insecticides. In situ, cohort-based life tables were used to structure, quantify, analyze and interpret the effects of natural enemies relative to the effects of other simultaneous mortality factors acting on pest populations in these systems. Results showed that single applications of selective insecticides initially functioned by replacing some mortality from predation and parasitism, and contributing an immediate, and essential, level of irreplaceable mortality. However, because these selective materials did not significantly disrupt natural enemies populations, parasitoids, and especially predators, were able to supply irreplaceable mortality that contributed to pest suppression for the remainder of the season. In contrast, repeated applications of conventional insecticides were required for pest control because natural enemy populations were reduced and unable to contribute significant irreplaceable mortality. This study demonstrates the role of multiple mortality factors in managing B. tabaci and provides a mechanistic understanding of the important contribution of conservation biological control.
Database assignments for author(s): Steven E. Naranjo, Peter C. Ellsworth

Research topic(s) for pests/diseases/weeds:
biocontrol - natural enemies
control - general

Pest and/or beneficial records:

Beneficial Pest/Disease/Weed Crop/Product Country Quarant.

Bemisia tabaci Cotton (Gossypium)