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United States Department of Agriculture

Agricultural Research Service

Title: Plant-Related Factors Influence the Effectiveness of Neoseiulus Fallacis (Acari: Phytoseiidae), a Biological Control Agent of Spider Mites on Landscape Ornamental Plants

Authors
item PRATT, PAUL
item Rosetta, Robin - OREGON ST UNIVERSITY
item Croft, Brian - OREGON ST UNIVERSITY

Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: July 1, 2002
Publication Date: December 20, 2002
Citation: Pratt, P.D., Rosetta, R., Croft, B.A. 2002. Plant-related factors influence the effectiveness of neoseiulus fallacis (acari: phytoseiidae), a biological control agent of spider mites on landscape ornamental plants. Journal of Economic Entomology.

Interpretive Summary: The predatory mite Neoseiulus fallacis (Garman) was evaluated as a biological control agent of pest mites on outdoor-grown ornamental landscape plants produced in the Pacific Northwest, USA. Ornamental landscape nurseries often produce a range of plants that are typically categorized into general morphological types, including conifers, shade trees, evergreen shrubs, deciduous shrubs and herbaceous perennials. These ornamentals can be produced as potted or field grown plants and are susceptible to a range of spider mite species. When testing the ability of N. fallacis to control spider mites on a representative range of these plant types, production methods and pest species, we found that the predator was most effective on shrubs and herbaceous perennials and less effective on conifers and shade trees. Neoseiulus fallacis was equally effective at controlling spider mites on containerized (potted) versus field grown plants and there was no difference in control of the spider mites regardless of pest species. Limited control by N. fallacis occurred mostly on tall, vertical plants with sparse canopies. These data suggest that N. fallacis can be an effective biological control agent of multiple spider mite species in a range of low-growing and selected higher-growing ornamental plants.

Technical Abstract: The predatory mite Neoseiulus fallacis (Garman) was evaluated as a biological control agent of herbivorous mites on outdoor-grown ornamental landscape plants. To elucidate factors that may affect predator efficiency, replicated tests were conducted on 30 ornamental plants that varied in relation to their generalized morphology (e.g. conifers, shade trees, evergreen shrubs, deciduous shrubs and herbaceous perennials), in production methods (potted or field grown), in canopy density and in the prey species present on each. Plant morphological grouping and foliar density appeared to be the most influential factors in predicting biological control. Among plant morphological groups, N. fallacis was most effective on shrubs and herbaceous perennials and less effective on conifers and shade trees. Neoseiulus fallacis was equally effective at controlling spider mites on containerized (potted) versus field grown plants and there was no difference in control of mites on plants with Tetranychus versus those with Oligonychus or Schizotetranychus species. Limited control by N. fallacis occurred mostly on tall, vertical plants with sparse canopies. Acceptable spider mite control occurred in 4 large-scale releases of N. fallacis into production plantings of Abies procera, Thuja occidentalis "Emerald", Malus rootstock and, Viburnum plicatum "Newport". These data suggest that N. fallacis can be an effective biological control agent of multiple spider mite species in a range of low-growing and selected higher-growing ornamental plants.

Last Modified: 9/10/2014
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