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| The State of Minnesota estabolished the Metropolitan Mosquito Control District (MMCD) in 1958. The following information was obtained from the Minnesota Office of the Legislative Auditor - Metropolitan Mosquito Control District Summary. The District's Mission: "promote health and well being by protecting the public from disease and annoyance caused by mosquitoes, black flies and ticks, in an environmentally sensitive manner." In 1985, MMCD created a 10-member independent research panel to oversee research on the effects of the District's larval insecticides. The scientific Peer Review Panel (SPRP) was composed of experts in biology and toxicology from several universities in the United States and Canada, as well as state and federal government agencies. The Scientific Peer Review Panel found that Bti and methoprene treatments had no adverse effects on aquatic micro-organisms (zooplankton), the reproduction of red-winged blackbirds, or the numbers of 18 other bird species. Mosquito Control Activities The District's primary focus is on 15 mosquito species that are either aggressive human biters or potential carriers of disease. It has identified over 65,000 mosquito breeding sites covering about 189,000 acres in the Twin Cities area. Each year since 1996 the District has increased the number of larval breeding acres treated and reduced the number of acres treated to kill adult mosquitoes. Bti accounted for 9 out of 10 acres treated to kill mosquito larvae, while resmethrin accounted for 9 out of 10 acres treated to kill adult mosquitoes between 1995 and 1998. Bti granules cost between $4.82 and $8.47 per acre, compared with over $52 per acre for methoprene pellets and over $388 per acre for methopreene briquets in 1997. Similarly, resmethrin cost between $1.00 and $1.66 per acre, compared with over $7.60 per acre for permethrin in 1997. Larval insecticides accounted over over 91% of total insecticide costs in 1997. Effectiveness Methoprene products used to kill cattail mosquito larvae have performed the best (92 to 99 percent control), while the average conrol achieved with Bti granules ranged from 78 to 89 percent control in 1995-1997. The Audit committee was unable to replicate MMCD's control figures for methoprene products used to kill floodwater mosquitoes. We recommend that the District reevaluate its use of methoprene briquets and pellets to control flodwater mosquito larvae, looking at both efficacy and cost factors. The District tested the effectiveness of resmethrin and permethrin used to kill adult mosquitoes in 1996, when it estimated that an average of 57% of adult mosquitoes were killed in treated sites. Based ont the results of District-sponsored studies in the early 1990's, the effectiveness of these adult insecticides appears to be questionable. In 1998, the District collected pre- and post-treatment adult mosquito counts. However, we havde some concerns about using these data to evaluatge the effectiveness of adult insecticides. We recommend that the District evaluate the Effectiveness of resmethrin and permethrin in scientifically designed and supervised field studies in 1999 and reexamine the role of adult mosquito treatments based on the results of its analysis. Dr. Bill suggests that New York State and Westchester County officials would better serve the public by reviewing the Minnesota record and check out other states who have set up panels and review committees to oversee effective larva and adult mosquito control |