VISUAL AND IMAGE SYSTEM MEASUREMENT OF SPRAY DEPOSITS USING WATERâSENSITIVE PAPER

Abstract

Watersensitive papers (WSP) were attached to leaves in nursery trees and sprayed with airblast sprayers.Deposit patterns on the WSP were rated visually for coverage, from 0 (no spots) to 10 (completely blue). Visual counts of spotdensity (spots/cm2) were made for cards representing coverage ratings from 1 to 6. WSPs were analyzed with an imagingsystem; several spot size parameters, number of spots, and area coverage percentage were measured. Visual ratings of 6, 7,and 8 had considerable variability in area coverage percentage. Sample WSPs with visual coverage ratings of 3, 5, 6, and8 and minimum, median, and maximum coverage percentages are presented. Visually measured spot density was greater thanimagesystem measured spot density for all rating numbers, especially for higher spot densities. Spot density began todecrease at visual rating numbers greater than 7.