Mosquito Control special report ///

Misting Matters
New research from Florida A&M University sheds light on automatic misting systems for the control of backyard mosquitoes.
By James E. Cilek, Charles F. Hallmon and Reginald Johnson

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tremendous amount of interest has been generated by pest control companies and industry in marketing and installing automatic misting systems for the purpose of reducing adult mosquitoes in residential areas. This technology has been primarily driven by homeowners who want to spend quality time in their backyards without being annoyed by host-seeking mosquitoes.
A typical automatic misting system consists of a multi-gallon reservoir connected to a continuous loop of rubber tubing attached to multiple single spray head nozzles. This array is then connected to a programmable electric pump set to automatically apply an insecticide at predetermined intervals (usually for 30 to 45 seconds at dusk and dawn when mosquitoes are most active). Nozzles are usually placed along

the perimeter of a backyard and in landscaping or other areas suitable for mosquito harborage.
Most systems usually apply a water-soluble synergized pyrethrins mixture.
Although most persons agree that the insecticides applied by these systems are capable of killing mosquitoes the long-term, effectiveness to reduce mosquito populations within a given area is lacking. The Florida state and local mosquito control community has questioned the effectiveness of automatic mist systems for the control of adult mosquitoes. As a result, an operational field research study recently published by the authors was funded in 2007 by the state of Florida, Department of Agriculture and Consumer Services to evaluate this technology (Cilek et al. 2008). A simulated residential backyard study with a misting system was also

installed on the grounds of Florida A&M University’s John A. Mulrennan, Sr. Public Health
Entomology Research & Education Center in
Panama City to determine the primary pathway of insecticide exposure to the mosquitoes under controlled conditions.
OPERATIONAL FIELD STUDY. The 35-week operational field study ran from March 22 to Nov.
16, 2007. A MistAway automatic misting system
(Model Gen 1.2, MistAway Systems, Houston,
Texas) previously installed by a local certified pest control firm in three residential backyards in northwestern Florida was the system that was evaluated. This pest control company leases the systems to homeowners and performs any maintenance, including insecticide refills.
The MistAway system is a continuous loop www.pctonline.com April 2009 ///

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system that uses 0.5 cm diameter rubber tubing connected to nondrip Hago #4023 nozzles.
Backyards in the study averaged about 55 feet deep by 85 feet wide with the entire perimeter area covered by the system. The number of nozzles per backyard ranged from 26 to 43 placed at
10-foot intervals. Nozzles were mounted about
3 to 4 feet above ground surface and were oriented at 45 degrees. The application system was attached to a 55-gallon drum reservoir that contained 0.05% AI solution of Summerfrost
(3% AI pyrethrins, 6% AI piperonyl butoxide, and 10% AI n-octyl bicycloheptene dicarboximide [MGK 264]). Systems were programmed to automatically apply a 45-second spray at dawn and another application at dusk. According to the manufacturer, system flow rate was 1.4 oz/ minute per nozzle at 180 psi.
The display panel on the unit also could be accessed to determine if the homeowner had overridden the system for additional sprays. No additional applications were noted during the study. Each treatment backyard was paired with an untreated yard at least 100 feet away.
Mosquito populations were monitored in all backyards with one ABC suction trap (Clarke
Mosquito Products, Roselle, Ill.) with the light on, powered by a 6v gel battery. All traps were baited with carbon dioxide dispensed from a
20-pound pressurized cylinder at a release rate of 500 ml/minute.