Taming a tiger in the city: comparison of motorized backpack applications and source reduction against the Asian tiger mosquito, Aedes albopictus.

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.