Variable-rate Spray Technology Optimizes Pesticide Application by Adjusting for Seasonal Shifts in Deciduous Perennial Crops

To optimize pesticide applications to the canopies of deciduous perennial crops, spray volume should be adjusted throughout the year to match the changes in canopy volume and density. Machine-vision, computer-controlled, variable-rate sprayers are now commercially available and claim to provide adeq...

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Main Authors: Lloyd L. Nackley, Brent Warneke, Lauren Fessler, Jay W. Pscheidt, David Lockwood, Wesley C. Wright, Xiaocun Sun, Amy Fulcher
Format: Article
Language:English
Published: American Society for Horticultural Science (ASHS) 2021-06-01
Series:HortTechnology
Subjects:
Online Access:https://journals.ashs.org/horttech/view/journals/horttech/31/4/article-p479.xml
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author Lloyd L. Nackley
Brent Warneke
Lauren Fessler
Jay W. Pscheidt
David Lockwood
Wesley C. Wright
Xiaocun Sun
Amy Fulcher
author_facet Lloyd L. Nackley
Brent Warneke
Lauren Fessler
Jay W. Pscheidt
David Lockwood
Wesley C. Wright
Xiaocun Sun
Amy Fulcher
author_sort Lloyd L. Nackley
collection DOAJ
description To optimize pesticide applications to the canopies of deciduous perennial crops, spray volume should be adjusted throughout the year to match the changes in canopy volume and density. Machine-vision, computer-controlled, variable-rate sprayers are now commercially available and claim to provide adequate coverage with decreased spray volumes compared with constant-rate sprayers. However, there is little research comparing variable- and constant-rate spray applications as crop characteristics change throughout a growing season. This study evaluated spray volume, spray quality (e.g., coverage and deposit density), and off-target spray losses of variable- and constant-rate sprayers across multiple phenophases in an apple (Malus domestica) orchard and a grape (Vitis vinifera) vineyard. The variable-rate sprayer mode applied 67% to 74% less volume in the orchard and 61% to 80% less volume in the vineyard. Spray coverage (percent), measured by water-sensitive cards (WSC), was consistently greater in the constant-rate mode compared with the variable-rate mode, but in many cases, excessive coverage (i.e., over-spray) was recorded. The variable-rate sprayer reduced off-target losses, measured by WSC coverage, up to 40% in the orchard and up to 33% in the vineyard. Spray application deposit densities (droplets per square centimeter) on target canopies were typically greater in variable-rate mode. However, the deposit densities were confounded in over-spray conditions because droplets coalesced on the WSC resulting in artificially low values (i.e., few, very large droplets). Spray efficiencies were most improved early in the growing season, when canopy density was lowest, demonstrating the importance of tailoring spray volume to plant canopy characteristics.
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spelling doaj.art-54930a04bf214361905ebbfe057948282022-12-21T18:42:36ZengAmerican Society for Horticultural Science (ASHS)HortTechnology1943-77142021-06-01314479489https://doi.org/10.21273/HORTTECH04794-21Variable-rate Spray Technology Optimizes Pesticide Application by Adjusting for Seasonal Shifts in Deciduous Perennial Crops Lloyd L. NackleyBrent WarnekeLauren FesslerJay W. PscheidtDavid LockwoodWesley C. WrightXiaocun SunAmy FulcherTo optimize pesticide applications to the canopies of deciduous perennial crops, spray volume should be adjusted throughout the year to match the changes in canopy volume and density. Machine-vision, computer-controlled, variable-rate sprayers are now commercially available and claim to provide adequate coverage with decreased spray volumes compared with constant-rate sprayers. However, there is little research comparing variable- and constant-rate spray applications as crop characteristics change throughout a growing season. This study evaluated spray volume, spray quality (e.g., coverage and deposit density), and off-target spray losses of variable- and constant-rate sprayers across multiple phenophases in an apple (Malus domestica) orchard and a grape (Vitis vinifera) vineyard. The variable-rate sprayer mode applied 67% to 74% less volume in the orchard and 61% to 80% less volume in the vineyard. Spray coverage (percent), measured by water-sensitive cards (WSC), was consistently greater in the constant-rate mode compared with the variable-rate mode, but in many cases, excessive coverage (i.e., over-spray) was recorded. The variable-rate sprayer reduced off-target losses, measured by WSC coverage, up to 40% in the orchard and up to 33% in the vineyard. Spray application deposit densities (droplets per square centimeter) on target canopies were typically greater in variable-rate mode. However, the deposit densities were confounded in over-spray conditions because droplets coalesced on the WSC resulting in artificially low values (i.e., few, very large droplets). Spray efficiencies were most improved early in the growing season, when canopy density was lowest, demonstrating the importance of tailoring spray volume to plant canopy characteristics.https://journals.ashs.org/horttech/view/journals/horttech/31/4/article-p479.xmlintelligent sprayerorchardpesticide driftphenologyprecision agriculturevineyard
spellingShingle Lloyd L. Nackley
Brent Warneke
Lauren Fessler
Jay W. Pscheidt
David Lockwood
Wesley C. Wright
Xiaocun Sun
Amy Fulcher
Variable-rate Spray Technology Optimizes Pesticide Application by Adjusting for Seasonal Shifts in Deciduous Perennial Crops
HortTechnology
intelligent sprayer
orchard
pesticide drift
phenology
precision agriculture
vineyard
title Variable-rate Spray Technology Optimizes Pesticide Application by Adjusting for Seasonal Shifts in Deciduous Perennial Crops
title_full Variable-rate Spray Technology Optimizes Pesticide Application by Adjusting for Seasonal Shifts in Deciduous Perennial Crops
title_fullStr Variable-rate Spray Technology Optimizes Pesticide Application by Adjusting for Seasonal Shifts in Deciduous Perennial Crops
title_full_unstemmed Variable-rate Spray Technology Optimizes Pesticide Application by Adjusting for Seasonal Shifts in Deciduous Perennial Crops
title_short Variable-rate Spray Technology Optimizes Pesticide Application by Adjusting for Seasonal Shifts in Deciduous Perennial Crops
title_sort variable rate spray technology optimizes pesticide application by adjusting for seasonal shifts in deciduous perennial crops
topic intelligent sprayer
orchard
pesticide drift
phenology
precision agriculture
vineyard
url https://journals.ashs.org/horttech/view/journals/horttech/31/4/article-p479.xml
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