Taming a Tiger in the City: Comparison of Motorized Backpack Applications and Source Reduction Against the Asian Tiger Mosquito,Aedes albopictus

Abstract

We evaluated 2 strategies to manage Aedes albopictus: 1) motorized backpack applications and 2) source reduction (coupled with hand-applied applications of larvicide). Backpack applications used a water-dispersible granular formulation (VectoBac WDG) of Bacillus thuringiensis var. israelensis (Bti), whereas source reduction used granular formulations of the insect growth regulator methoprene (Altosid) combined with a monomolecular film surfactant (Agnique). Six subplots (total 8.02 ha) were selected for backpack applications, source reduction, and control groups. The experiments were blind with applications conducted randomly and independently. Efficacy was determined through placement of bioassay cups with larvae within experimental plots 1 day before treatment. Backpack applications resulted in 76% (+/- 8.2% SE) and source reduction resulted in 92% (+/- 4.1% SE) larval mortality. Backpack applications required 50 times less labor than source reduction (0.25 versus 0.005 ha/h). The cost of backpack applications, including labor, was $159.88/ha, compared with $659.65/ha for source reduction. Although overall efficacy was slightly lower, motorized backpack applications of Bti were more efficient and cost-effective than source reduction methods to control Ae. albopictus in urban settings at the community level.

Wide area spray of bacterial larvicide, Bacillus thuringiensis israelensis strain AM65-52, integrated in the national vector control program impacts dengue transmission in an urban township in Sibu district, Sarawak, Malaysia

“…The drainage system consisting of earth and concrete drains in this site was also generally blocked by discard containers. All outdoor containers exposed to rain or sewer water provide a suitable harbourage for the colonization of dengue vectors [25][26][27][28]. In the larvae survey conducted in 2015-2016 in 4 ongoing dengue hotspot sites in Malaysia, it was identified that the highest number of positive containers were found outdoors and these outdoor containers were 3.5 folds more productive than indoor containers.…”

“…In the pilot operational field efficacy study in 2015, the impact of Bti treatment on Aedes spp mosquito population was determined by making comparisons between the treated (Z-7L) and the control (Z-5) sites for Aedes index (AI), larval density (LD) and ovitrap index (OI). The comparisons were made between the sites at 3 different phases: pre Bti treatment phase (EW 19-23); Bti treatment phase (EW [24][25][26][27][28][29][30][31][32][33][34][35]; and post Bti treatment phase (EW 36-41). All analyses were conducted using IBM Statistical Package for Social Science software (SPSS) ver.…”

“…Source reduction, covering 400 m from the case house, is another one of the key control measures included in the MOH dengue control program [8], but it is a near impossible feat to search and destroy all the cryptic receptacles. In New Jersey, USA it was found that removing and discarding disposable containers, together with hand-treating container habitats that could not be removed, were less efficient and less cost-effective than motorized backpack applications of Bti [27].…”

Targeting a Hidden Enemy: Pyriproxyfen Autodissemination Strategy for the Control of the Container Mosquito Aedes albopictus in Cryptic Habitats

“…albopictus , including discarded tires, trash, soda cans, plant pots, bird baths, corrugated drain pipes etc., is extremely challenging and labor intensive [5,6]. In addition, mosquito control agencies find it difficult to get access to the private properties where these habitats are located [8]. Moreover, accumulation of containers such as beverage cans and other trash are hard to manage because they are often rapidly re-generated.…”

“…For instance, Bacillus thuringiensis var. israelensis is a well-established larvicide used for mosquito control, particularly in urban areas, with proven efficacy [8,10]. It is imperative for any larvicide application to reach concealed cryptic habitats, where this mosquito prefers to oviposit.…”