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Experiments to determine effects of predator releases on populations ofOligonychus punicae [Acarina: Tetranychidae] on avocado in California

Research paper by J. A. McMurtry, H. G. Johnson, M. H. Badii

Indexed on: 01 Mar '84Published on: 01 Mar '84Published in: BioControl



Abstract

To determine the effect of predator releases in suppressing populations ofOligonychus punicae (Hirst), 9 species ofPhytoseiidae were released in single-tree replicated plots in an avocado orchard at rates of 1200 mites/tree over a 4-week period. The releases did not significantly affect average densities ofO. punicae or total phytoseiids. However, the percentages of the released species in the total phytoseiid populations reached 40, 38, 29, 28, and 22 forPhytoseiulus macropilis (Banks),Amblyseius limonicus (Garman & McGregor),Iphiseius degenerans (Berlese),Amblyseius californicus (McGregor), andTyphlodromus occidentalis Nesbitt, respectively.Phytoseiulus longipes Evans,Euseius concordis (Chant),E. stipulatus (A.-H.), andE. tutsi (Pritchard & Baker) increased little following the releases.