Cross posting from Dplex-L Email List
http://www.monarchwatch.org/dplex/index.htm
From: Karen Oberhauser
Date: Sat, Jul 21, 2012 at 10:25 AM
Dear Monarch Watchers,
I've published two studies on the impacts of mosquito spraying on monarchs. Most mosquito control district use a variety of different pyrethroids in mosquito abatement efforts, and these can be sprayed as ULV (ultra low volume, or aerosol) treatments, or as barrier treatments. The ULV treatments affect insects as they're flying, and the barrier treatments remain on leaves, providing a barrier to mosquitoes that harbor in wooded or shrubby areas during the day and come out at dawn or dusk. While it is generally thought that the formulations of permethrin used for mosquito control do not pose unreasonable risks to wildlife or the environment (U.S. EPA 2003), our study is one of the few that has examined the nontarget effects of barrier applications of permethrin on foliage-inhabiting arthropods, like monarchs. Both studies showed impacts on monarch larvae AND adults, with leaves from the barrier treatments resulting in higher mortality than control groups up to 3 weeks after application.
The references to these papers are below. The PDFs can be accessed from my website, which is here (click on the publications link): http://fwcb.cfans.umn.edu/oberhauser/
Oberhauser, K.S, S. Manweiler, R. Lelich, M. Blank, R. Batalden, A. De Anda. 2009. Impacts of ULV resmethrin applications on non-target insects. Journal of the American Mosquito Control Association 25:83–93.
Oberhauser, K. S., S. J. Brinda, S. Weaver, R. D. Moon, S. A. Manweiler, N. Read. 2006. Growth and survival of monarch butterflies (Lepidoptera: Danaidae) after exposure to permethrin barrier treatments. Environ. Entomol. 35 (6): 1626-1634.
On another note, many of the ppt and poster presentations from the Minnesota Monarch Meeting are posted on the meeting website: http://www.monarchlab.org/mn2012/Presentations.aspx
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Karen Oberhauser
Associate Professor and Director of Graduate Studies, Conservation Biology
Department of Fisheries, Wildlife, and Conservation Biology
University of Minnesota
612 624-8706
http://fwcb.cfans.umn.edu/oberhauser/