Field Efficacy Trials of Aerial Ultra-Low-Volume Application of Insecticides Against Caged Aedes aegypti in Mexico.

We evaluated the efficacy of aerial ultra-low-volume (ULV) insecticide spraying in field bioassays with caged Aedes aegypti in May 2017 in Puerto Vallarta, Jalisco, Mexico. The insecticides tested included an organophosphate (Mosquitocida UNO ULV) and a neonicotinoid-pyrethroid combination (Cielo). Two Ae. aegypti populations were evaluated: a field pyrethroid-resistant local strain (Puerto Vallarta) and an insecticide-susceptible laboratory strain (New Orleans). Knockdown after 1 h by both products was ≥97.0%, and mortality after 24 h was ≥98% for the susceptible laboratory strain. Knockdown of the local Puerto Vallarta field strain by both products after 1 h was ≥96.5%; and mosquito mortality after 24 h was also very high (≥98%). Meteorological conditions during this evaluation were favorable for aerial mosquito control and represented conditions that typically occur during adulticide space spray applications. Temperature oscillated between 24°C and 26°C with winds between 6 and 10 km/h. The majority of droplets met the droplet distribution criteria required for the insecticides. The evaluation demonstrated an acceptable performance of both products for Ae. aegypti control when applied undiluted at a rate of 199.4 ml/ha and 73.07 ml/ha for Mosquitocida UNO ULV and Cielo, respectively. The volume median diameter (VMD) droplet size was characterized at 31.3 µm and 37.3 µm, respectively.

Bioefficacy of Two Nonpyrethroid Insecticides for Targeted Indoor Residual Spraying Against Pyrethroid-Resistant Aedes aegypti.

We evaluated the efficacy of bendiocarb (Ficam W® 80%) and pirimiphos-methyl (Actellic 300CS® 28.16%), applied to different surfaces potentially sprayable within houses during the application of a targeted indoor residual spraying (TIRS) against a field pyrethroid-resistant strain of Aedes aegypti. Bioassays with cones were performed on cement (walls), wood (doors), and textile (cloth) surfaces within typical houses in the Mexican city of Merida (n = 10). Optimal residual efficacy (>80% of mean mortality) of bendiocarb ranged from 3 months (cement) to 2 months (wood and textiles). Residual efficacy of pirimiphos-methyl ranged from 5 months (cement) to 2 months (wood and textiles). Both insecticides proved to be effective as adulticides against field Ae. aegypti and may be useful in mosquito control programs implementing TIRS with pyrethroid-resistant populations.