Optimizing the performance of mosquito gravid traps for improved disease surveillance and control

Mosquitoes are the most important vectors of diseases; placing more than half of the world’s population in tropical and subtropical regions in risk of acquiring devastating infections.  The problem is spreading into temperate climate, as a result of climate change.  With such threat, there is a need for standardized trapping methods that allow comparison between mosquito populations at different locations.  The present study was designed to optimize the performance of the mosquito Gravid Trap (GT) by comparing the efficacy of traps baited by different types of infusions and determining and quantitation of the physical and chemical parameters associated with increased trap efficiency.  Work was also done to test effects of adding biorational larvicides to the traps.  Gravid traps baited with hay infusion, hay and chicken manure infusion and untreated water control were tested side by side in two locations in Somerset and Wicomico counties, Maryland, USA.   Chemical and physical characteristics of the three types of media were recorded throughout the experiment.  The results indicated that the combination of chicken manure and hay infusion attracted higher numbers of female mosquitoes as compared to hay infusion and water media. Most mosquitoes attracted to the traps were Culex spp; primarily Cx. pipiens and Cx. restuans.  Preliminary data indicated that the differential attraction to different media may be related to changes in pH, dissolved oxygen content, conductivity and salinity of water.  Future research should determine specific microbial composition and odors that are responsible for mediating the attractancy of different infusions.