The effect of phorate on wetland macroinvertebrates

Authors

  • Charles D. Dieter,

    Corresponding author
    1. Department of Wildlife and Fisheries, South Dakota State University, Brookings, South Dakota 57007, USA
    • Department of Wildlife and Fisheries, South Dakota State University, Brookings, South Dakota 57007, USA
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  • Lester D. Flake,

    1. Department of Wildlife and Fisheries, South Dakota State University, Brookings, South Dakota 57007, USA
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  • Walter G. Duffy

    1. South Dakota Cooperative Fish and Wildlife Research Unit, National Biological Survey, Brookings, South Dakota 57007, USA
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Abstract

The effects of phorate, an organophosphorus insecticide, on aquatic macroinvertebrates was studied in littoral mesocosms in South Dakota wetlands. In 1991 and 1992, four mesocosms were constructed in each of three wetlands. In each wetland, one mesocosm was a reference and phorate concentrations of 1.2, 2.4, and 4.8 kg/ha were applied to treatment mesocosms. Phorate caused mortality to amphipods and chironomids throughout the study. Leeches and snails were resistant to phorate. Few living macroinvertebrates were present in mesocosms after phorate treatment and populations recovered only slightly after 1 month. Macroinvertebrate taxa that were sensitive to phorate included: Odonata, Hemiptera, Culicidae, Heliidae, Ephemeroptera, Acarina, Coleoptera, Stratio-myidae, and Hydracarina. Taxa that were tolerant to phorate included: Hirudinea, Gastropoda, Oligochaeta, and Ostracoda.

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