Semi-field evaluation of novel chemical lures using standard traps for vector mosquitoes (Diptera: Culicidae) in Thailand

Entomological surveillance is important to evaluate vector management efficacy and estimate disease transmission threshold. The BioGents Sentinel (BGS) trap baited with BG-lure was developed and regarded as the closest in comparison and possible replacement for human-landing catches for epidemiologically relevant monitoring of adult Aedes aegypti. We evaluated novel chemical lure candidates in semi-field screen house using two commercial traps, namely BGS trap and Blackhole UV light trap against diurnal Ae. aegypti and nocturnal Culex quinquefasciatus. L-lactic acid-based Kasetsart University (KU)-lure #1 treated BGS-traps exhibited the greatest percent attraction for the Ae. aegypti (29.5 ± 14.3) while different chemical portion of KU-lure #6 attracted the most Cx. quinquefasciatus (33.3 ± 10.7). Interestingly, a pack of BG-lure (10 g) treated BGS-traps was not significantly attracted both females compared to untreated BGS-traps (p = 0.482 and p = 0.350 for Ae. aegypti and Cx. quinquefasciatus, respectively). Meanwhile, 250ml/min of flow rated CO₂ demonstrated the most attractant efficacy for both species (42.2 ± 14.2 and 75.1 ± 16.9, respectively). Subsequently, trap efficacy between BGS and Blackhole UV light trap was compared using the nocturnal species. Both traps significantly increased the percent attraction with KU-lure #6 (p = 0.007 and 0.040 for BGS and Blackhole, respectively) and the percent attraction between traps with the KU-lure #6 was not significantly different (p = 0.280). Further studies to develop species-specific lure is urgently necessary to increase the trap efficacy for each local vector mosquito in Thailand.