Efficacy of several commercially formulated essential oils against caged female Aedes albopictus and Culex quinquefasciatus when operationally applied via an automatic-timed insecticide application system

Abstract

The effectiveness of several commercially available products containing plant essential oils against caged female Aedes albopictus and Culex quinquefasciatus was studied. Products operationally applied via an automatic-timed insecticide application system (MistAway) at maximum label rates were EcoExempt MC (9.0 ml/liter, rosemary oil [18% AI], cinnamon oil [2% AI], lemongrass oil [2% AI], plus 78% "other ingredients" in wintergreen oil). Misting System Concentrate (4 ml/liter, oil of Juniperus virginiana [85% AI]), Mosquito Barrier (31.1 ml/liter, garlic oil [99.3% AI], and citric acid [0.5% AI]), and No-See-Um Organic Repellent (99.5 ml/liter, lemongrass [4% AI], citronella [3% AI], castor oil [3% AI], sodium laurate [3%], and garlic oil [1% AI] in an 86% [AI] mixture of wintergreen oil, lecithin, and water). All products were compared with a commercial formulation of synergized pyrethrins, Riptide (9.0 ml/liter, pyrethrins [5% AI], piperonyl butoxide [25% AI]), as a standard. Mortality was the greatest for Riptide to both mosquito species with effectiveness influenced by distance from the nozzle (ranging from > 80% at 3 m to > 10% at 20 m). The essential oil products resulted in < 10% mortality for each species regardless of application exposure distance with the exception of EcoExempt, which gave approximately 13% mortality of caged female Ae. albopictus 6 m from the nozzles.