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United States Department of Agriculture

Agricultural Research Service

Title: Comparison of Electrostatic and Coldfog Sprayers Using Cold Field Emission Scanning Electron Microscopy and Energy Dispersive X-Ray Microanalysis

item Krause, Charles
item Derksen, Richard

Submitted to: Brighton Conference Symposium Proceedings
Publication Type: Proceedings
Publication Acceptance Date: September 9, 2000
Publication Date: N/A

Interpretive Summary: Floral crops grown in the United States are valued at over $5 billion annually. However, growers must spray their crops with fungicides to control diseases that reduce the quality and salability of these crops. Two relatively new types of sprayer systems, electrostatic and coldfog sprayers, were tested to determine the uniformity of fungicide and tracer chemical spray coverage. A cold field emission scanning electron microscope was used to measure the residue. This new type of microscope combined with another instrument, an energy dispersive x-ray analyzer, permitted chemical analysis and photography of droplet residues of less than 1/million inch in diameter, revealing a unique Abasketweave@ type crystal structure. Studies indicated that the electrostatic sprayer provided better coverage that the coldfog sprayer. The above research could lead to a reduction of pesticide usage with more efficient disease congrol, ,benefitting the farmer and consumer.

Technical Abstract: Handgun-type electrostatic and coldfog sprayers were evaluated in a production greenhouse. Spray distribution and canopy penetration were measured using cold field emission scanning electron microscopy (CFESEM) with energy dispersive x-ray analysis. When both instruments are used together, the technique is termed as cold field emission electron beam analysis (CFE-EBA). This unique, alternative imaging assessment method improved clarity and resolution resulting in higher magnification of fungicide/tracer residue, not previously available with conventional thermionic scanning electron microscopes. The use of CFESEM minimized specimen preparation time by eliminating the need for coating and other histological procedures. CFE-EBA indicated that the electrostatic sprayer used in this study demonstrated superior coverage over that of the coldfog sprayer.

Last Modified: 5/5/2015
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