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Evaluation of Predaceous Mite Releases for Spider Mite Management

Ramana G. Colfer, Jay A. Rosenheim, Larry D. Godfrey and Cynthia L. Hsu


Predatory mite releases can be an effective means to manage spider mites in many perennial cropping systems, yet little research has been performed in annual cropping systems. In earlier research, large scale releases of the western predatory mite Galendromus occidentalis in cotton at low release rates were unsuccessful in reducing spider mites. Here, we describe two experiments that evaluate: (1) predaceous mite releases under conditions of high initial spider mite densities, high predatory mite release rates, and low hemipteran predator densities; and, (2) the relative impact of generalist insect predators Geocoris spp., Orius tristicolor, and Frankliniella occidentalis on the persistence of the western predatory mite Galendromus occidentalis and how these predator-predator interactions influence spider mite control. The first experiment showed that predatory mite releases can increase predatory mite populations; these predator populations can increase their abundance through recruitment; and they can suppress spider mite populations. We do not know if similar results can be obtained under unmanipulated field conditions where the environment may be less optimal for predatory mite population growth. The second experiment demonstrated that hemipteran predators can have a negative impact on predatory mite persistence but can improve spider mite suppression. No detectable impact of F. occidentalis was observed on either G. occidentalis or spider mite populations.

Reprinted from Proceedings of the 1998 Beltwide Cotton Conferences pp. 976 - 982
©National Cotton Council, Memphis TN

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Document last modified Sunday, Dec 6 1998