What alternatives are there to using insecticides ?
Since no insecticide can guarantee zero impact on the natural environment and complete eradication of the nuisance, other methods must be explored to limit this nuisance.
Better management of these areas
The mosquitoes concerned by mosquito control operations (Ochlerotatus caspius and O. detritus), formerly called Aedes, lay their eggs at the base of vegetation, in small depressions, on dry or damp land. Only female mosquitoes bite, because the blood they draw provides them with the proteins needed for their eggs to mature. These eggs can wait for several weeks, or even several years, before entering into contact with water naturally (because of precipitation or sea storms) or artificially (due to human intervention), which will start the development of the larvae and lead to the synchronised hatching of the adults a few days later. The EID estimates that approximately 25 to 30% of the production of mosquitoes is the result of artificially created wet areas (rice fields and marshes used for grazing, hunting, or nature reserves). These areas are often flooded in the summer, that is during the high tourist season, when the nuisance caused by the mosquitoes is considered to be the most serious. Therefore, a significant decrease in the nuisance could realistically be achieved by simply modifying the calendar for flooding these areas (date and frequency). Likewise, the renovation of the shores of artificial bodies of water (rice fields, hunting marshes) to make their slopes vertical and vegetation free, could help significantly reduce at a low cost the nuisance by decreasing the number of potential egg laying sites.
The use of selective traps
A new type of trap that attracts and destroys mosquitoes and other biting insects (such as midges) has recently appeared on the market. Intended for private use, these traps use propane gas and are apparently odour-free, clean, and silent, and do not emit any more CO2 than a human being at rest. The EID confirms the very selective nature of the trap, which is generally effective over a range of 25 to 65 m according to the model.
These two alternatives are interesting from an ecological point of view, and also economic given the high cost of the methods that use insecticides. For instance, mosquito control using Bti for only the Salin de Giraud area would cost €997,000 per year, according to an EID estimate in 2005.