Large-Volume Gravid Traps Enhance Collection ofCulexVectors

Abstract

Gravid mosquito collections were compared among several large-volume (infusion volume ≥35 liters) gravid trap designs and the small-volume (infusion volume = 6 liters) Centers for Disease Control and Prevention (CDC) gravid trap used routinely by vector control districts for vector and pathogen surveillance. The numbers of gravid Culex quinquefasciatus, Cx. tarsalis, and Cx. stigmatosoma collected by large gravid traps were greater than by the CDC gravid trap during nearly all overnight trials. Large-volume gravid traps collected on average 6.6-fold more adult female Culex mosquitoes compared to small-volume CDC gravid traps across 3 seasons during the 3 years of the studies. The differences in gravid mosquito collections between large-versus small-volume gravid traps were greatest during spring, when 8- to 56-fold more Culex individuals were collected using large-volume gravid traps. The proportion of gravid females in collections did not differ appreciably among the more effective trap designs tested. Important determinants of gravid trap performance were infusion container size and type as well as infusion volume, which determined the distance between the suction trap and the infusion surface. Of lesser importance for gravid trap performance were the number of suction traps, method of suction trap mounting, and infusion concentration. Fermentation of infusions between 1 and 4 wk weakly affected total mosquito collections, with Cx. stigmatosoma collections moderately enhanced by comparatively young and organically enriched infusions. A suction trap mounted above 100 liters of organic infusion housed in a 121-liter black plastic container collected the most gravid mosquitoes over the greatest range of experimental conditions, and a 35-liter infusion with side-mounted suction traps was a promising lesser-volume alternative design.

Surveillance and Control of Culex quinquefasciatus Using Autocidal Gravid Ovitraps

“…The AGO trap is set up with 8 liters of water and a 30-g hay pack that decomposes over time, providing olfactory cues for gravid mosquitoes to lay eggs. Producing the infusion with the hay pack in situ or within the trap when it is already at the collection site has the advantage of not having to transport large quantities of liquid infusion that was fermented elsewhere to set up gravid traps (e.g., Popko and Walton 2016). Trap servicing occurs every 8 wk, which worked well for Ae.…”

Size of Openings in Water-Holding Containers: Impact on Oviposition by Culex (Culex) Mosquitoes

“…coronator populations throughout the state increases the potential for this mosquito to serve as a vector of West Nile virus [26]. Efforts to develop better gravid traps for mosquito and arbovirus surveillance have been focused mainly on various types of infusions and related attractant and the lesser extent other features of the traps [9,27,28,29,30,31]. Generally gravid traps capture far more Cx.…”

“…Containers baited with hay infusion or some other type of attractant are important components of gravid traps [8] and increasing both container and aperture size may result in improved capture rates for some species [9]. Distinguishing the impact of container size versus aperture size on mosquito collections can be problematic since larger containers often have larger apertures [10].…”

Integrating Vector and Nuisance Mosquito Control for Severe Weather Response

“…Programs legally tasked and developed solely for vector-borne disease control lacked necessary surveillance data on floodwater, nuisance species due to variations in the traps used for diseasecarrying mosquitoes and their nuisance counterparts. Gravid traps are commonly used to collect Culex mosquitoes looking to oviposit their eggs in stagnant, nutrient-rich water (Li et al 2016, Popko andWalton 2016). The BG-Sentinel traps use a lure that attracts Ae.…”