Efficacy of Bacillus thuringiensis treatment on Aedes population using different applications at highrise buildings

Abstract

Bacillus thuringiensis israelensis (Bti) is an effective biological insecticide for killing mosquito larvae. However, choosing the suitable application method for larviciding is critical in increasing its effectiveness. Therefore, this study aimed to determine the effectiveness of Bti (VectoBac®) WG using various applications at high-rise buildings. Three different applications of Bti treatment were applied at three high-rise buildings in Bandar Saujana Putra. The ULV machine is used for Pangsapuri Impian, a mist blower for Pangsapuri Seri Saujana and a pressured sprayer for BSP 21. BSP Skypark does not undergo treatment and acts as a control. The efficacy of Bti treatment was measured by analyzing the ovitrap surveillance data collected (POI and MLT) for pre and post-treatment. Post-treatment ovitrap surveillance indicates that the Aedes sp. mosquito density was lower than the density at the time of pre-treatment surveillance. Overall, the Aedes albopictus species in both an indoor and outdoor environment setting had shown a reduction. The highest Aedes sp. density reduction is seen through the use of mist blowers in outdoor settings for Aedes albopictus, (%POI reduction = 87.4%; %MLT reduction = 93.8%). The mist blower yielded results that is significantly higher compared to other larviciding applications; the order from greatest to the least was mist blower > pressured sprayer > ULV. It can be concluded that each application produces different degrees of effectiveness in reducing the Aedes sp. density in different environmental settings.