It isn’t too difficult to find adult mosquitoes – stand in the woods or bait a mosquito trap with carbon dioxide and you’ll have plenty in no time! However, mosquito larvae are aquatic and often inhabit murky and polluted, or highly-vegetated waters that can make finding them challenging. To better quantify larval mosquito activity in these habitats, we often set traps designed to catch mosquitoes emerging from the water (emergence traps) in both of these situations.
The main mosquito vector of West Nile virus in our parish prefers to lay her eggs in polluted water. Concentrated organics in this water not only make it difficult to quantify larval activity within, they also drive away predatory fish from the area. The use of emergence traps in these roadside ditch habitats is essential for quantifying the amount of mosquito production within clean and polluted waters, as well as everything in between.
Some of the most aggravating nuisance mosquitoes in St. Tammany Parish are found in their larval stage solely within dense mats of water hyacinth plants. These mosquitoes attach to the root of this aquatic weed, and are undetectable from the water surface. Emergence trapping was used in these habitats to determine which plant species fostered mosquitoes, and is still used to this day to quantify larval abundance over time.