Canopy density may be affected by pruning practices, tree vigor, time of season, or cultivar, but tree size also affects canopy density. These experiments support the concept that rates of chemicals applied per hectare should be reduced to obtain similar chemical deposits for small and large trees and for more open and dense canopies. In Experiments 1 and 2, the trees were fully foliated. Data presented here suggest adjustments in the TRV rate should be considered for vertical tree training systems between and within blocks. However, because the Lincoln canopy had a deep, dense canopy that split the air pattern, a vertical air volume would be required to penetrate this canopy.
Sprayer designs now greatly limit adjustments on a per tree basis within a block.
An ultrasonic electronic tree canopy sensing device and individual nozzle controls similar to those designed by Giles et al. Literature Cited Byers, R. E., C. G. Lyons, Jr., K. S. Yoder, and R. L. Horsburgh. 1984. Effects of apple tree size and canopy density on spray chemical deposit. Byers, R. E., C. G. Lyons, Jr., and S. J. Donohue. Effect of chemical deposits from spraying adjacent rows on efficacy of peach bloom thinners.