Canopy spray application technology in specialty crops: a slowly evolving landscape

Warneke, Brent; Zhu, Heping; Pscheidt, Jay William; Nackley, Lloyd L.

doi:10.1002/ps.6167

Cited by 18 publications

(11 citation statements)

References 39 publications

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“…These results suggest that apple orchard foliage density was never as dense as the constant-rate spray mode was designed to cover. Excessive spray has previously been attributed to the fact that constant-rate spray systems were designed for historical orchard systems in which the trees were much larger and denser (Warneke et al, 2020). Greater spray volumes can decrease application efficiency, spray penetration, droplet uniformity, and create runoff that is transferred to the ground (Miranda-Fuentes et al, 2015).…”

Section: Discussionmentioning

confidence: 99%

“…Costs associated with pesticide applications (e.g., chemicals, equipment, labor) can account for 30% or more of the annual operating costs for an orchard (Bechtel et al, 1995) or a vineyard (Sambucci et al, 2014). Airassisted sprayers are used throughout the world to apply insecticides and fungicides to orchards, vineyards, and other specialty crop production systems (Warneke et al, 2020). Air-assisted sprayers deliver pesticides by atomizing droplets of an aqueous chemical mixture into a high-velocity air stream.…”

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confidence: 99%

“…The blast of air is designed to displace the air in the crop canopy with a stream of pesticide droplets. Air-assisted sprayers were originally designed to apply pesticides to large fruit trees, often 20 ft or more in height at maturity, but modern fruit orchards often produce on trees 6 to 12 ft tall (Fox et al, 2008;Warneke et al, 2020). Therefore, standard airassisted sprayers are often overpowered for modern crops and eject droplets above and beyond the canopy, whereby some droplets escape into the atmosphere (Grella et al, 2019 plants are often undersprayed or oversprayed (Fessler et al, 2020).…”

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confidence: 99%

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

Nackley

Warneke

Fessler

et al. 2021

hortte

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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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Section: Discussionmentioning

confidence: 99%

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confidence: 99%

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confidence: 99%

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

Nackley

Warneke

Fessler

et al. 2021

hortte

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“…The leaf, as the most important component of the canopy, occupies 80% of the canopy and serves as the main air-bearing object [23] . Petroff et al [24] studied the particle sedimentation characteristics of a broad-leaved canopy under different wind velocities, pointing out that canopy size, leaf shape and inclination angle are important factors that influence particulate matter deposition. In summary, many studies on droplet-leaf interaction are based on static target leaves, and research on dynamic target leaves and spray droplet interactions is rare.…”

Section: Introduction mentioning

confidence: 99%

Effects of leaf response velocity on spray deposition with an air-assisted orchard sprayer

Li¹,

Li²,

Ma³

et al. 2021

International Journal of Agricultural and Biological Engineering

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The interaction between leaves and airflow has a direct effect on the droplet deposition characteristics of the leaf canopy. In order to make clear the mechanism of droplet deposition in terms of the interaction between the droplets and leaves from the point of the leaf aerodynamic response velocity, the leaf movement under different airflow velocities and the influence of the leaf aerodynamic response on droplet coverage ratio were investigated. The effect of the aerodynamic response velocity of a leaf on the droplet deposition of the leaf surface was investigated. The aerodynamic characteristics of the leaf were analyzed theoretically. Boundary layer theory from fluid mechanics was used to develop a model of the leaf aerodynamic response velocity to nonperiodic excitations based on a convolution integral method. Target leaf aerodynamic velocities were detected using a high-speed camera, and the results indicated that the modeled leaf aerodynamic response velocity matched the measured values. At given conditions of spray liquid and leaf surface texture, the spray test showed that the droplet coverage ratio was influenced by the leaf aerodynamic response velocity, the droplet coverage ratio increased and then decreased with the leaf response velocity. Through analyze four droplets deposition state, the highest droplet deposition ratio and best deposition state on the leaf surface occur when the leaf aerodynamic response velocity was less than 0.14 m/s. According to the analysis of droplet deposition states, the uniformity of the droplet size and quantity distribution of droplets on the leaf surface related to the leaf aerodynamic response velocity. The results can provide a basis for the design and optimization of orchard air sprayers.

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“…These activities include the use of air-induction nozzles, the use of decision support tools [1,[6][7][8], and injection into trunk trees of plant protection products [9]. In addition, the use of the latest advanced sprayers equipped with various sensors reduces the risk of hazards [10,11]. Scientists have also presented results of research on the exposure of bystanders to the drift liquid.…”

Section: Introductionmentioning

confidence: 99%

Average Degree of Coverage and Coverage Unevenness Coefficient as Parameters for Spraying Quality Assessment

Cieniawska

Pentoś

2021

Agriculture

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The purpose of the research was to determine the influence of selected factors on the average degree of coverage and uniformity of liquid spray coverage using selected single and dual flat fan nozzles. The impact of nozzle type, spray pressure, driving speed, and spray angle on the average degree of coverage and coverage unevenness coefficient were studied. The research was conducted with special spray track machinery designed and constructed to control and change the boom height, spray angle, driving speed, and spray pressure. Based on the research results, it was found that the highest average coverage was obtained for single standard flat fan nozzles and dual anti-drift flat fan nozzles. At the same time, the highest values of unevenness were observed for these nozzles. Inverse relationships were obtained for air-induction nozzles. Maximization of coverage with simultaneous minimization of unevenness can be achieved by using a medium droplet size for single flat fan nozzles (volume median diameter (VMD) = 300 μm) and coarse droplet size for dual flat fan nozzles (VMD = 352 μm), with low driving speed (respectively 1.1 m∙s−1 and 1.6 m∙s−1) and angling of the nozzle by 20° in the opposite direction to the direction of travel.

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Canopy spray application technology in specialty crops: a slowly evolving landscape

Cited by 18 publications

References 39 publications

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

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

Effects of leaf response velocity on spray deposition with an air-assisted orchard sprayer

Average Degree of Coverage and Coverage Unevenness Coefficient as Parameters for Spraying Quality Assessment

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