U.S. flag

An official website of the United States government

Dot gov

Official websites use .gov
A .gov website belongs to an official government organization in the United States.


Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.


Main content area

Assessment of spray deposition with water-sensitive paper cards

Masoud Salyani, Heping Zhu, Roy D. Sweeb, Naresh Pai
CIGR ejournal 2013 v.15 no.2 pp. 101-111
Citrus, droplets, image analysis, nozzles, paper, pesticide application, spatial distribution, spray coverage, spray deposition, spray volume, systems analysis
Spatial distributions of spray droplets discharged from an airblast sprayer, were sampled on pairs of absorbent paper (AP) and water-sensitive paper (WSP) targets at several distances from the sprayer. Spray solutions, containing a fluorescent tracer, were discharged from two size nozzles to achieve low and high volume rates commonly used in citrus applications. Spray deposits on AP targets were measured by fluorometry and spray coverage areas on WSP cards were assessed by three independent image analysis systems. Generally, there were good correlations (R2 = 0.9085 to 0.9748) among the three imaging systems in measuring WSP percent area coverage. Lower volume rate (smaller droplets) provided more useful WSP targets than higher volume rate (larger droplets). Overall, there were somewhat weak correlations between WSP area coverage and AP spray deposition measurements. Volume median diameter and number of droplet stains on WSP cards , obtained by only two imaging systems, showed noticeable differences between the measurements of the two systems.