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.