Introduction to symposium on attractants for mosquito surveillance and control

Over the past few decades public concern about potential health and environmental hazards that result from the use of broad-spectrum insecticides for controlling insect pests, including mosquitoes, has increased and become more vocal. In addition to the general public's concern, many environmental groups are demanding a pesticide-free environment. In response to these concerns and demands, environmental protection agencies have had legislation enacted or proposed that bans or places rigid use restrictions on an increasing number of pesticides. The overall impact of this environmental legislation on mosquito control is that there are now fewer adulticides available than at any other time during the past 20 years (Rathburn I 990). Rathburn (1990) further states that manufacturers and formulators have withdrawn several existing insecticides and formulations for 2 primary reasons. First, there is the high cost ofreregistration due to additional research required by the Environmental Protection Agency (EPA) to determine the environmental impact of these pesticides on humans or nontarget organisms. Second, there is the increased cost of production for a limited market, as compared with th€ more extensive agricultural market. Industry is reluctant to make the investments necessary to discover, develop, and demonstrate safety ofnew pesticides because ofthe time, risks, and high costs involved. Meanwhile mosquitoes continue to produce offspring that may become resistant to currently approved insecticides. Development of resistance will further limit the availability of suitable insecticides. For these reasons, operational mosquito control personnel are becoming concerned about the possibility that satisfactory insecticides may not be available in the near future. Thus, the need to perfect alternate mosquito control strategies is becoming increasingly urgent. This increased concern has provided the impetus to evaluate the potential ofattractant traps/ targets. Much of the optimism for this approach is based on the success that tsetse workers have had with attractant-baited, insecticide-impregnated targets in Zimbabwe (Vale 1993). Until the mid-1980s tsetse control in Zimbabwe was achieved by the broadcast ofendosulfan or deltamethrin from the airor the application of DDT from the ground (Allsopp 1984). Since then, steadily increased use of targets led to the complete replacement of spraying in I 99 I (Vale I 993). There is a nucleus of researchers worldwide that have a renewed interest in exploring the use of attractants as alternatives to currently used technology for surveillance and control of mosquitoes. This group was invited to participate in the First International Symposium on Hematophagous Insect Attractants, sponsored by the Metropolitan Mosquito Control District, Minneapolis, MN, in November 1989. Twenty-five scientists from the United States, Canada, the United Kingdom, and the Netherlands participated in this symposium. The consensus of this group ofscientists was that attractants could play a significant role in the control and surveillance ofhematophagous insects. The extent ofthat role was the subject of much discussion. The major outcome of this meeting was the agreement that an informal working group should be formed to organize workshops and symposia for the exchange ofideas and information. It was proposed that these meetings be held on an annual or biennial basis in association with major entomological meetings throughout the world. Four symposia and 3 workshops have been held since 1989. In 199 I this working group became closely afrliated u.ith the AMCA through the establishment of the AMCA Ad Hoc Attractants committee. t This symposium was co-organized by D. L. Kline, J. Day, and W. Takken. Financial aid for travel and publication costs for some ofthe participants was provided by S. C. Johnson & Son, Inc., I 525 Howe Street, Racine, WI 53403, and Zoecon Corporation, a division of Sandoz Corporation, 12200 Denton Drive. Dallas. TX 75234.