Knockdown and lethal effects of three mosquito coil formulations against Aedes aegypti and Culex quinquefasciatus under different nutritional conditions

Abstract Three mosquito coil formulations, each containing either metofluthrin 0.025% w/w, d-allethrin 0.225% w/w, or esbiothrin 0.10% w/w were evaluated for knockdown and killing properties against laboratory populations of female Aedes aegypti (L.) and Culex quinquefasciatus Say under different nutritional-energy sources of blood, sucrose, and water. The tests were conducted in a 70 cm × 70 cm × 70 cm glass chamber. Mosquito responses were measured by knockdown times during the 20-min exposure period and mortality at 24 h post-exposure. The results showed the metofluthrin coil provided the most rapid knockdown for both test species and regardless of nutritional condition compared with the other two coils. Metofluthrin and d-allethrin were highly effective in killing Ae. aegypti (95–100% mortality), whereas esbiothrin produced 100% mortality to water-fed mosquitoes and 78.3 and 80% mortality for blood- and sucrose-fed specimens, respectively. >85% mortality was observed in sucrose- and water-fed Cx. quinquefasciatus against metofluthrin, while 78.3% blood-fed females survived exposure. This species showed very low mortality with d-allethrin (3.3% to 28.3%), with the highest mortality recorded (71.7%) for water-fed with esbiothrin. Overall, Ae. aegypti was more sensitive to all three coil products than Cx. quinquefasciatus. The mortality between species and nutritional conditions showed significant differences for all comparisons except for sucrose-fed mosquitoes exposed to metofluthrin.