CHARACTERIZATION OF TRUCK-MOUNTED ATOMIZATION EQUIPMENT TYPICALLY USED IN VECTOR CONTROL¹

Abstract

The control of medically important arthropod vectors of human and animal disease is a high priority for both public health and military officials. Because droplet size of pesticide spray material is a critical factor affecting vector control applications, the droplet-size spectra produced by 11 sprayers and 3 spray formulations were evaluated. Droplet-size spectra were measured by a laser diffraction instrument, a hot-wire system, and rotating slides. There were considerable differences in the droplet-size spectra produced by the different sprayers tested. The volume median diameter (Dv0.5) for the water-based sprays ranged from 4.7 to 211 microm, depending on the sprayer, and the percent of spray volume contained in droplets less than 20 microm (%vol <20 microm) ranged between 0.5% and 98.9%. The Dv0.5 measurements for the oil-based sprays ranged from 9.4 to 125.3 microm and the %vol <20 microm ranged between 2.4% and 97.9%. The correlations between the Dv0.5 measured by the laser system (Dv0.5-laser) and the mass median diameter, Sauter diameter, and Dv0.5 measured by the AIMS probe were all significant. Generally, the slide Dv0.5s were numerically similar to the Dv0.5 from the laser system and the Sauter diameter from the Army Insecticide Measuring System probe. There was less consistent agreement between the % <32 microm values obtained from the slides and those from the other 2 samplers. The information presented can be used by applicators to select the sprayer that produces the droplet-size spectra needed for their particular application situation.

Spray Characterization of Thermal Fogging Equipment Typically Used in Vector Control1

“…There was a wide range in the droplet size spectra produced by the different sprayers tested. This variety in equipment performance is similar to that reported for handheld vector control equipment (Hoffmann et al 2007b) and truck-mounted equipment (Hoffmann et al 2007a).…”

Evaluation of ULV Applications Against Old World Sand Fly (Diptera: Psychodidae) Species in Equatorial Kenya

“…The compressor provides airßow at the rate of 0.3 m 3 /min at 690 kPa, with a spray ßow rate of 88.7Ð117.4 ml/min. Laboratory evaluation by Hoffmann et al (2007) found that the Terminator with a No. 24 oriÞce produces D V0.1 of 3.6 m, D V0.5 of 17.2 m, and D V00.9 of 38.8 m, with 56.6% of droplets Ͻ20 m when applying a test material of BVA 13 ULV oil.…”

“…The Grizzly has a laminar air ßow (IHPLAT) nozzle and the sprayerÕs maximum ßow rate is 500 ml/min. Laboratory evaluation by Hoffmann et al (2007) found that the Grizzly produces D V0.1 of 3.5 m, D V0.5 of 17.5 m, and D V0.9 of 38.6 m, with 56.4% of droplets Ͻ20 m when applying a test material of BVA 13 ULV oil. In the Þeld we carried out a calibration run with the Grizzly on ßow rate setting #7 and determined it to produce a ßow rate of 303 ml/min for this study.…”

Research Contributing to Improvements in Controlling Florida’s Mosquitoes and Mosquito-borne Diseases

“…Studies provided information on the importance of the adulticide droplet size on the effectiveness of aerial ULV [27,31,32], the calibration of spray, dosage rates and effects of different spray systems on droplet size spectrums [33,34,35,36,37], the importance of meteorological effects on adulticide applications [27,35,38,39,40,41], barriers to adulticide effectiveness [26,42,43,44], improvements to measure pesticide residues to reduce non-target effects [45], and tests to gauge the non-target effects of mosquito control ULV pesticides [46,47,48,49,50]. …”