A Field Evaluation of Four Larval Mosquito Control Methods in Urban Catch Basins

Abstract

Effective control of mosquitoes in rural Midwestern communities that lack organized mosquito control districts would be aided by baseline data on optimal breeding sites, interannual effects of climate on population emergence and abundance, and efficacy of various control options under field conditions. During 19 surveillance weeks in the summer of 2005, we sampled 100 catch basins each week that were distributed among 10 study zones. Catch basins within each study zone were subjected to 1 of 4 different mosquito control methods or were left untreated. Of the 10 study zones, 5 were in high-intensity urban areas and 5 in low-intensity urban areas. During the study period, treatment of urban catch basins with Altosid XR extended residual briquets resulted in a 69.5% reduction in mosquito larvae numbers. However, the product did not provide sustained treatment for the 120-150 days suggested by the manufacturer. Vectolex WSP, when applied according to manufacturer's suggestions, resulted in a 73.4% reduction in mosquito larvae. VectolexWSP effectiveness was impacted by heavy rainfalls early in the surveillance period. Cleaning catch basins once or twice during the surveillance period resulted in a 40.1% and a 39.9% reduction in mosquito larvae, respectively. Catch basins in high-intensity urban areas comprised 27.7% of the total collection compared to 72.3% from low-intensity urban areas. The AltosidXR extended residual briquets and the VectolexWSP products both impacted the number of mosquito larvae collected. However, a single treatment to control mosquitoes in this study area may not be sufficient. We suggest that treatment of urban catch basins is optimized when accompanied by a comprehensive surveillance plan, and that a combination of treatments or multiple treatments during the season may be necessary to mitigate risks of vector-borne infectious diseases in areas with similar climate and precipitation trends.

Reduced productivity ofCulex pipiensandCx. restuans(Diptera: Culicidae) mosquitoes in parking area catch basins in the northeast Chicago metropolitan area

“…As suspected, catch basins in parking areas were surrounded by more impervious surface and fewer trees, similar to the characteristics of the "high-density urban areas" described by Kronenwetter-Koepel et al (2005) and Stockwell et al (2006). And, similar to those previous studies, parking area sites held catch basins that produced mosquitoes at a rate of 30% or less than that of residential street catch basins which were surrounded by less impervious surface and more trees.…”

“…The following year and in the same study area, Stockwell et al (2006) observed that 50 catch basins sampled weekly in similarly-named "highintensity" urban areas (<20% of land area covered in vegetation) held a little more than a third of the mosquitoes found in 50 basins in "low-intensity" urban areas (areas mixed with impervious surfaces and vegetation). Those authors suggested that a factor in these observed differences may have been the volume of organic debris captured in basin sumps.…”

“…Deciduous trees were chosen for this parameter as they were expected to produce greater volumes of leaf debris over time than coniferous trees and were the most common type of tree near basins. The site characteristics are similar to those used to characterize "high-and low-intensity" urban areas of Kronenwetter-Koepel et al (2005) and Stockwell et al (2006). The location of basins in relation to curbs (curbside vs open pavement) was also investigated.…”

“…Kronenwetter‐Koepel et al () found that seven untreated catch basins sampled weekly in “high‐intensity” urban areas (with >50% impervious land cover) held about 15% of the mosquitoes found in seven untreated basins in “low‐intensity” urban areas (21 to <50% impervious land cover). The following year and in the same study area, Stockwell et al () observed that 50 catch basins sampled weekly in similarly‐named “high‐intensity” urban areas (<20% of land area covered in vegetation) held a little more than a third of the mosquitoes found in 50 basins in “low‐intensity” urban areas (areas mixed with impervious surfaces and vegetation). Those authors suggested that a factor in these observed differences may have been the volume of organic debris captured in basin sumps.…”

“…Their design often includes a sump or vault below the outflow pipe that collects sediments and other debris, preventing this material from entering and clogging the outflow pipes. These sumps are often deep enough to permanently hold water and as a result, provide a habitat for aquatic stages of mosquito vector species, including Culex pipiens L., Culex quinquefasciatus Say, and Culex restuans Theobald (Covell and Resh 1971, Munstermann and Craig 1977, Stockwell et al 2006, Anderson et al 2011, Rydzanicz et al 2016, Cx. quinquefasciatus (Say) (Maddock et al 1963, Rey et al 2006, Molaei et al 2007, Aedes albopictus (Skuse) (Prioteasa et al 2015, Vallorani et al 2015 and Ae.…”