Location: Fruit and Tree Nut ResearchTitle: The Effect of Tractor Speed, Volume and a Volute on Spray Deposition in Tall Pecan Trees
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 5/13/2020
Publication Date: 12/1/2020
Citation: Bock, C.H., Hotchkiss, M.W. 2020. The Effect of Tractor Speed, Volume and a Volute on Spray Deposition in Tall Pecan Trees. Meeting Abstract. Vol 110, No. 12S. https://doi.org/10.1094/PHYTO-110-12-S2.1.
Interpretive Summary: Abstract Only.
Technical Abstract: Scab (caused by Venturia effusa) is the major disease of pecan in the southeastern US. In epidemic seasons yield loss is substantial in susceptible cultivars. Fungicide coverage from air-blast sprayers declines with height in the canopy. How application volume (L/ha), speed (kph) and use of a volute influence deposition (% area) at different heights is unknown. Deposition was quantified using kromekote cards and vision pink dye at heights of 5, 7.2, 9.4, 11.6, 13.8, 15, 17.2 and 19.2 m using a patternator, and at 5, 7.5, 10, 12.5 and 15 m in tree canopies. A 3785 L air-blast sprayer was used at 468, 935 and 1871 L/ha at 2.4 and 3.2 kph. A volute was also tested at 468 and 935 L/ha at 2.4 and 3.2 kph using the patternator. Nozzles were selected to provide proportionally similar volumes to the upper and lower canopy positions at set speeds. Speeds tested did not affect deposition. However, without a volute, higher volumes resulted in significantly greater deposition in the canopy, but most of that increase was at heights <12.5 m. Although significant differences existed at =12.5 m, they were numerically small. In this study use of a volute resulted in more uniform deposition at all heights, but numerically or significantly more at heights >15 m, but less at heights <15 m compared to other treatments. The study demonstrates that higher volumes result in more deposition, but the effect declines rapidly with height. Volutes may increase deposition at heights >15 m.