USE OF IMAGE ANALYSIS FOR MEASUREMENT OF INSECTICIDE DROPLETS FROM ULTRA-LOW VOLUME SPRAYS

Abstract

The use of computer image analysis (IA) for the measurement of droplets from ULV aerosols collected on teflon-coated microscope slides was evaluated through direct comparisons with the conventional method which uses a compound microscope with an ocular micrometer scale. No statistically significant difference was found in the accuracy of either method. Changing the subject performing droplet measurements with the conventional method had a significant effect on the droplet volume median diameter (VMD) determined, while with the IA method droplet VMDs were not significantly different. Repeated measurement of droplets indicated that the IA method was a more precise method overall. The majority of test subjects (3 of 5) found that the time required to measure 100 droplets using the conventional method was significantly greater than the IA method. The IA method provides a viable alternative to the conventional technique of droplet size measurements in applications where aerosol analyses are frequent, a large number of samples are taken, a high level of precision is required, the persons doing the measurements are changing, and finances are not too restrictive.