Mosquito Management on National Wildlife Refuges, Ecosystem Effects Study. Phase II, Part 1 - Effects of Ultra Low Volume Applications of Pyrethrin, Malathion and Permethrin on Macro-Invertebrates in the Sacramento National Wildlife Refuge, California

Metadata Updated: October 10, 2019

Mosquito control districts often use ultra-low volume (ULV) applications of insecticides to control adult mosquitoes. Few field studies have tested the effects of these applications on non-target species. We quantified the effect of ULV applications of synergized pyrethrin, permethrin, and malathion on non-target invertebrates and mosquitofish inhabiting seasonal wetlands on the Sutter and Colusa National Wildlife Refuges (NWR)s in central California. Synergized pyrethrin was applied over three irrigated fields at Sutter NWR, and malathion and permethrin were each applied over two fields at Colusa NWR. There were three control fields at each site. We monitored the abundance, biomass, and species composition of aquatic invertebrates before and after treatments, analyzed water samples for pesticide residue, counted flying insects 'knocked down' by the treatments, trapped flying insects (Colusa only), and tracked survival of caged adult and larval mosquitoes and mosquitofish. Survivorship of larval mosquitoes indicated whether pesticides were deposited in the water in quantities lethal to aquatic insects. We also tested the efficacy of pyrethrin against mosquitoes in riparian vegetation. No reductions were detected in the total abundance or biomass of aquatic macro-invertebrates in treated or control fields in any trial. Aquatic Coleoptera and Ephemeroptera showed lower post-treatment abundances in one treated field each (permethrin and malathion, respectively) but not in the other of the same treatment. Larval mosquitoes showed high survival in all treated and control fields. Mosquitofish died from unrelated causes at Sutter NWR, but all survived at Colusa NWR. All adult mosquitoes died when caged over fields treated with malathion and permethrin. All survived in control fields, indicating that insecticide did not drift into control areas. Abundances of flying insects decreased in both treated and control fields when insecticides were applied, Flying insect abundance rebounded 24 h later in both sets of fields. Our tests of the efficacy of ULV application of pyrethrin in riparian vegetation showed that few caged adult mosquitoes died when wind speeds were approximately 1 mph, but mortality was evident when wind speed was 8- 10 mph. Higher wind speeds allow better penetration of the vegetation. The results of our study suggest that ULV applications of these insecticides for the control of adult mosquitoes do not substantially affect the abundance of aquatic macro-invertebrates or fish in treated wetlands. The reasons for this are discussed.

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Public: This dataset is intended for public access and use. License: No license information was provided. If this work was prepared by an officer or employee of the United States government as part of that person's official duties it is considered a U.S. Government Work.

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Metadata Created Date May 1, 2019
Metadata Updated Date October 10, 2019

Metadata Source

Harvested from DOI CKAN Harvest Source

Additional Metadata

Resource Type Dataset
Metadata Created Date May 1, 2019
Metadata Updated Date October 10, 2019
Publisher Fish and Wildlife Service
Unique Identifier FWS_ServCat_23269
Brent Frakes
Maintainer Email
Public Access Level public
Bureau Code 010:18
Metadata Context
Metadata Catalog ID C:\Program Files (x86)\FWS\DataStore\Application\OpenData\FWS_ServCat_v1_1.json
Schema Version
Catalog Describedby
Data Quality true
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Harvest Object Id 39051fee-c007-4273-b9c0-8cd776ac999e
Harvest Source Id 34ce571b-cb98-4e0b-979f-30f9ecc452c5
Harvest Source Title DOI CKAN Harvest Source
Data First Published 1998-01-01
Homepage URL
Data Last Modified 1998-01-01
Program Code 010:094, 010:028
Related Documents ""
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Source Hash 1d77e14a63cf52768a68faef5cfc73dfd4d822a8
Source Schema Version 1.1
Spatial -122.195076,39.0119934,-121.727043,39.4512329
Category "Unpublished Report"

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