scholarly journals Reducing the Nursery Pesticide Footprint with Laser-guided, Variable-rate Spray Application Technology

HortScience ◽  
2021 ◽  
pp. 1-13
Author(s):  
Lauren Fessler ◽  
Amy Fulcher ◽  
Liesel Schneider ◽  
Wesley C. Wright ◽  
Heping Zhu
Keyword(s):  
Powdery Mildew ◽  
Variable Rate ◽  
Spray Application ◽  
Pesticide Application ◽  
Air Blast ◽  
Growing Seasons ◽  
Wide Range ◽  
Application Characteristics ◽  
Deposit Density ◽  
Control Disease

Nursery producers are challenged with growing a wide range of species with little to no detectable damage from insects or diseases. Growing plants that meet consumer demand for aesthetics has traditionally meant routine pesticide application using the most time-efficient method possible, an air-blast sprayer, despite its known poor pesticide application efficiency. New variable-rate spray technology allows growers to make more targeted applications and reduce off-target pesticide loss. In this study, a prototype laser-guided variable-rate sprayer was compared with a traditional air-blast sprayer. Pesticide volume, spray application characteristics, and the control of powdery mildew were evaluated over the course of two growing seasons. Spray application characteristics were assessed using water-sensitive cards (WSCs) and DepositScan software. This prototype sprayer reduced pesticide volume by an average of 54% across both years despite being tested against a low rate (<250 L⋅ha−1). In 2016, the conventional sprayer had more than double the deposit density on target WSCs among distal trees than the variable-rate sprayer; however, within proximal trees, there was no difference between the two sprayer types. In 2017, when the trees were larger, within both the distal and proximal trees, the conventional sprayer had greater deposit density on target WSCs than the variable-rate sprayer. In 2016, coverage on target WSCs was nearly 7-fold greater with the conventional treatment than with the variable-rate treatment. In 2017, when trees were larger, there was greater coverage on target WSCs in proximal trees (3.8%) compared with those in distal trees (1.0%) regardless of the sprayer type. This variable-rate spray technology provided acceptable control of powdery mildew severity on individual branches and whole trees and maintained the incidence of powdery mildew to levels comparable to that occurring among trees sprayed with a traditional air-blast sprayer. Therefore, the variable-rate spray technology has the potential to effectively control disease, dramatically reduce the pesticide footprint, and preserve natural resources such as ground and surface water, soil, and beneficial insects found within and around nurseries.

scholarly journals Advancing Sustainability in Tree Crop Pest Management: Refining Spray Application Rate with a Laser-guided Variable-rate Sprayer in Apple Orchards

HortScience ◽  
2020 ◽  
Vol 55 (9) ◽  
pp. 1522-1530
Author(s):  
Lauren Fessler ◽  
Amy Fulcher ◽  
Dave Lockwood ◽  
Wesley Wright ◽  
Heping Zhu
Keyword(s):  
Cost Savings ◽  
Application Rate ◽  
Variable Rate ◽  
Spray Application ◽  
Laser Rangefinder ◽  
Pesticide Application ◽  
Nontarget Organisms ◽  
Sensing Technology ◽  
Spray Rate ◽  
Deposit Density

Advanced variable-rate spray technology, which applies pesticides based on real-time scanning laser rangefinder measurements of plant presence, size, and density, was developed and retrofitted to existing sprayers. Experiments were conducted to characterize the application of four programmed spray rates (0.03, 0.05, 0.07, or 0.09 L·m−3 of crop geometric volume) when applied to Malus domestica Borkh. ‘Golden Delicious’ apple trees using this crop sensing technology. Water-sensitive cards (WSCs) were used as samplers to quantify spray coverage, deposits, and deposit density in the target and nontarget areas, and an overspray index based on a threshold of greater than 30% coverage was calculated. The application rate ranged from 262 L·ha−1 at the programmed spray rate of 0.03 L·m−3 to 638 L·ha−1 at the rate of 0.09 L·m−3. For a given WSC position, spray coverage and deposits increased as the spray rate increased. WSC positions 1 and 2 were oversprayed at all rates. The effect of spray rate on deposit density varied with WSC positions, with high densities achieved by low spray rates for WSCs closest to the sprayer but by high spray rates for WSCs positioned either deeper within or under the canopy. When coalescing deposits were accounted for, deposit densities met or exceeded the recommended pesticide application thresholds (insecticides 20–30 droplets/cm2; fungicides 50–70 droplets/cm2) at all WSC positions for each spray rate tested. The lowest spray rate reduced off-target loss to the orchard floor by 81% compared with the highest rate, dramatically reducing potential exposure to nontarget organisms, such as foraging pollinators, to come into contact with pesticide residues. Applying the lowest rate of 0.03 L·m−3 met deposit density efficacy levels while reducing spray volume by 83% compared with the orchard standard application of 1540 L·ha−1 and by 87% compared with the 1950 L·ha−1 application rate recommended when using the tree row volume method. Thus, there is potential for growers to refine pesticide application rates to further achieve significant pesticide cost savings. Producers of other woody crops, such as nursery, citrus, and grapes, who use air-assisted sprayers, may be able to achieve similar savings by refining pesticide applications through the use of laser rangefinder-based spray application technology.

scholarly journals Control of Insects and Diseases with Intelligent Variable-rate Sprayers in Ornamental Nurseries1

2019 ◽  
Vol 37 (3) ◽  
pp. 90-100 ◽  
Author(s):  
Liming Chen ◽  
Matthew Wallhead ◽  
Heping Zhu ◽  
Amy Fulcher
Keyword(s):  
Powdery Mildew ◽  
Apple Scab ◽  
Pesticide Use ◽  
Cornus Florida ◽  
Variable Rate ◽  
Malus Pumila ◽  
Platanus Acerifolia ◽  
Growing Seasons ◽  
Constant Rate ◽  
Malus Pumila Mill

Abstract Intelligent spray technology can reduce pesticide use and safeguard the environment; however, its ability to effectively control insects and disease must be validated before its adoption by growers. Comparative tests for two different laser-guided variable-rate intelligent sprayers and the same sprayers with conventional constant-rate mode were conducted to control pests at two ornamental nurseries in two growing seasons in Ohio. Crabapple [Malus ‘Sutyzam’ (Sugar Tyme®), M. sargentii], apple (Malus pumila), maple [Acer ×freemanii ‘Jeffersred' (Autumn Blaze®), A. rubrum ‘Franksred' (Red Sunset®) and A. rubrum], birch (Betula nigra and Betula populifolia ‘Whitespire'), London planetree (Platanus ×acerifolia ‘Bloodgood') and dogwood (Cornus florida) were used as the test plants. Intelligent spray technology reduced pesticide use by 56.1% and 51.8% on average at the two nurseries, respectively. Compared to conventional air-assisted sprayers, severity of scab on apple trees and powdery mildew in dogwood was reduced on intelligent spray-treated plants at one nursery, and there were equal or fewer leafhoppers in maple trees and aphids in birch trees when sprayed using intelligent spray technology at both nurseries. These results suggest that intelligent, variable-rate sprayers achieve equivalent or greater insect and disease control in ornamental tree nurseries compared to conventional, constant-rate sprayers. Index words: aphid, apple scab, environmental protection, leafhopper, precision spray, powdery mildew, sustainable. Species used in this study: apple (Malus pumila Mill), birches (Betula nigra L, Betula populifolia Marsh. ‘Whitespire'), crabapples [Malus ‘Sutyzam' (Sugar Tyme®), M. sargentii Rehder], dogwood (Cornus florida L.), maples [Acer ×freemanii E. Murray ‘Jeffersred' (Autumn Blaze®), A. rubrum L. ‘Franksred'(Red Sunset®) and A. rubrum L.], London planetree [Platanus ×acerifolia (Ait.) Willd. ‘Bloodgood'].

Management of grape powdery mildew with an intelligent sprayer and sulfur

Plant Disease ◽  
2022 ◽  
Author(s):  
Brent Warneke ◽  
Lloyd Nackley ◽  
Jay W. Pscheidt
Keyword(s):  
Powdery Mildew ◽  
Pacific Northwest ◽  
Pulse Width Modulation ◽  
Variable Rate ◽  
Agricultural Commodity ◽  
Air Blast ◽  
Spray System ◽  
Constant Rate ◽  
Spray Rate ◽  
Grape Powdery Mildew

Wine grapes are an important agricultural commodity in the Pacific Northwest where grape powdery mildew (GPM) is one of the main disease problems. The efficacy of different sulfur concentrations and different output volumes from an air blast sprayer retrofitted with the Intelligent Spray System (ISS) were evaluated for the management of GPM. The ISS consists of a LiDAR sensor, Doppler speed sensor, embedded computer, flow controller, and individual pulse-width-modulation solenoid valves at each nozzle. GPM cluster severity ranged from 55% to 75% across all trials in the study when using the ISS at its default spray rate of 62.5 ml m-3 and micronized sulfur at 6 g L-1, which was significantly higher than all other fungicide treatments, but lower than non-treated controls. Similarly, leaf incidence values were highest on non-treated vines, followed by micronized sulfur at 6 g L-1 applied at 62.5 ml m-3 , with all other fungicide treatments being significantly lower in all trials. Using the ISS at the 62.5 ml m-3 rate and a rotation of locally systemic fungicides resulted in the lowest observed GPM leaf incidence, and average cluster severity of 11% in both 2019 and 2020, the lowest cluster severity of all fungicide treatments tested. GPM control using the ISS and micronized sulfur was equivalent to a constant-rate air blast treatment at 6 g L-1 when the spray rate of the ISS was increased to 125ml m-3, or if the concentration of sulfur was increased to 24 g L-1. In those cases, the amount of sulfur applied to vines was at or above the minimum label rate from bloom until the end of the season, or the entire season, respectively. This study has shown that sufficient disease control cannot always be expected when mixing pesticides at the same rate as would be used for a constant-rate sprayer in a variable rate sprayer, especially when using contact fungicides like sulfur . With appropriate adjustments, the variable-rate ISS can be a useful tool to reduce pesticide quantities, water required for mixing, and as a result labor, as fewer trips to refill for a given spray event are required.

Long-term Effects of Triazol Growth Regulators on Stem Elongation of Rhododendron and Kalmia

HortScience ◽  
1997 ◽  
Vol 32 (3) ◽  
pp. 436E-436
Author(s):  
Martin P.N. Gent
Keyword(s):  
Dose Response ◽  
Growth Regulator ◽  
Stem Elongation ◽  
Spray Application ◽  
Long Term Effects ◽  
Potted Plants ◽  
Response Coefficient ◽  
Wide Range ◽  
Second Year

The persistence of effects of paclobutrazol or uniconazol on stem elongation was determined for several years after large-leaf Rhododendron and Kalmia latifolia were treated with a single-spray application of these triazol growth-regulator chemicals. Potted plants were treated in the second year from propagation, and transplanted into the field in the following spring. The elongation of stems was measured in the year of application and in the following 2 to 4 years. Treatments with a wide range of doses were applied in 1991, 1992, or 1995. For all except the most-dilute applications, stem elongation was retarded in the year following application. At the highest doses, stem growth was inhibited 2 years following application. The results could be explained by a model of growth regulator action that assumed stem elongation was inversely related to amount of growth regulator applied. The dose response coefficient for paclobutrazol was less than that for uniconazol. The dose that inhibited stem elongation one-half as much as a saturating dose was about 0.5 and 0.05 mg/plant, for paclobutrazol and uniconazol, respectively. The dose response coefficient decreased exponentially with time after application, with an exponential time constant of about 2/year. The model predicted a dose of growth regulator that inhibited 0.9 of stem elongation immediately after application would continue to inhibit 0.5 of stem elongation in the following year.

scholarly journals Re-Evaluation of the Podosphaera tridactyla Species Complex in Australia

2021 ◽  
Vol 7 (3) ◽  
pp. 171
Author(s):  
Reannon L. Smith ◽  
Tom W. May ◽  
Jatinder Kaur ◽  
Tim I. Sawbridge ◽  
Ross C. Mann ◽  
...  
Keyword(s):  
Phylogenetic Analysis ◽  
Powdery Mildew ◽  
Species Complex ◽  
Taxonomic Revision ◽  
Stone Fruit ◽  
Prunus Species ◽  
Wide Range ◽  
Unidentified Species ◽  
The Rose ◽  
Generation Sequencing

The Podosphaera tridactyla species complex is highly variable morphologically and causes powdery mildew on a wide range of Prunus species, including stone fruit. A taxonomic revision of the Po. tridactyla species complex in 2020 identified 12 species, seven of which were newly characterised. In order to clarify which species of this complex are present in Australia, next generation sequencing was used to isolate the fungal ITS+28S and host matK chloroplast gene regions from 56 powdery mildew specimens of stone fruit and ornamental Prunus species accessioned as Po. tridactyla or Oidium sp. in Australian reference collections. The specimens were collected in Australia, Switzerland, Italy and Korea and were collected from 1953 to 2018. Host species were confirmed using matK phylogenetic analysis, which identified that four had been misidentified as Prunus but were actually Malusprunifolia. Podosphaera species were identified using ITS+28S phylogenetic analysis, recognising three Podosphaera species on stone fruit and related ornamental Prunus hosts in Australia. These were Po.pannosa, the rose powdery mildew, and two species in the Po. tridactyla species complex: Po. ampla, which was the predominant species, and a previously unidentified species from peach, which we describe here as Po. cunningtonii.

scholarly journals Rattail fescue (Vulpia myuros) interference and seed production as affected by sowing time and crop density in winter wheat

Weed Science ◽  
2020 ◽  
pp. 1-10
Author(s):  
Muhammad Javaid Akhter ◽  
Per Kudsk ◽  
Solvejg Kopp Mathiassen ◽  
Bo Melander
Keyword(s):  
Winter Wheat ◽  
Grain Yield ◽  
Seed Production ◽  
Yield Components ◽  
Field Experiments ◽  
Growing Season ◽  
Sowing Time ◽  
Growing Seasons ◽  
Crop Density ◽  
Wide Range

Abstract Field experiments were conducted in the growing seasons of 2017 to 2018 and 2018 to 2019 to evaluate the competitive effects of rattail fescue [Vulpia myuros (L.) C.C. Gmel.] in winter wheat (Triticum aestivum L.) and to assess whether delayed crop sowing and increased crop density influence the emergence, competitiveness, and fecundity of V. myuros. Cumulative emergence showed the potential of V. myuros to emerge rapidly and under a wide range of climatic conditions with no effect of crop density and variable effects of sowing time between the two experiments. Grain yield and yield components were negatively affected by increasing V. myuros density. The relationship between grain yield and V. myuros density was not influenced by sowing time or by crop density, but crop–weed competition was strongly influenced by growing conditions. Due to very different weather conditions, grain yield reductions were lower in the growing season of 2017 to 2018 than in 2018 to 2019, with maximum grain yield losses of 22% and 50% in the two growing seasons, respectively. The yield components, number of crop ears per square meter, and 1,000-kernel weight were affected almost equally, reflecting that V. myuros’s competition with winter wheat occurred both early and late in the growing season. Seed production of V. myuros was suppressed by delaying sowing and increasing crop density. The impacts of delayed sowing and increasing crop density on seed production of V. myuros highlight the potential of these cultural weed control tactics in the long-term management programs of this species.

scholarly journals Evidence for improved pollen viability as the mechanism for film antitranspirant mitigation of drought damage to wheat yield

2016 ◽  
Vol 67 (2) ◽  
pp. 137 ◽  
Author(s):  
Minuka M. Weerasinghe ◽  
Peter S. Kettlewell ◽  
Ivan G. Grove ◽  
Martin C. Hare
Keyword(s):  
Grain Yield ◽  
Field Experiments ◽  
Pollen Viability ◽  
Wheat Yield ◽  
Spray Application ◽  
Grain Number ◽  
Climatic Zones ◽  
Boot Stage ◽  
Wide Range ◽  
Drought Damage

Application of film antitranspirant to wheat during late stem extension reduces drought damage to yield, but the mechanism is unknown. Field experiments under rain shelters were conducted over 3 years to test the hypothesis that film antitranspirant applied before meiosis alleviates drought-induced losses of pollen viability, grain number and yield. The film antitranspirant di-1-p-menthene was applied at third-node stage, and meiosis occurred at the early boot stage, with a range of 11–16 days after spray application in different years. Irrigated, unsprayed plots were included under the rain-shelters, and pollen viability, measured in 2 years in these plots, averaged 95.3%. Drought reduced pollen viability to 80.1% in unirrigated, unsprayed plots, but only to 88.6% in unirrigated plots treated with film antitranspirant. Grain number and yield of irrigated plots, measured in all years, were 16 529 m–2 and 9.55 t ha–1, respectively, on average. These were reduced by drought to 11 410 m–2 and 6.31 t ha–1 in unirrigated, unsprayed plots, but only to 12 878 m–2 and 6.97 t ha–1 in unirrigated plots treated with film antitranspirant. Thus compared with unirrigated, unsprayed plots, antitranspirant gave a grain yield benefit of 0.66 t ha–1. Further work is needed to validate the pollen viability mechanism in different climatic zones and with a wide range of cultivars.

Seismic phases and scaling associated with small high-explosive surface shots

1981 ◽  
Vol 71 (6) ◽  
pp. 1731-1741
Author(s):  
I. N. Gupta ◽  
R. A. Hartenberger
Keyword(s):  
Blast Wave ◽  
Rayleigh Waves ◽  
Wave Train ◽  
Simple Wave ◽  
P Wave ◽  
Peak Ground Velocity ◽  
Air Blast ◽  
Geological Conditions ◽  
Wide Range ◽  
First Arrival

Abstract An analysis of seismic field data from surface shots in two radically different geologic environments shows significantly different seismic phases at the two sites. At the first site, which has a layered sedimentary section, five distinct phases are observed: the P-wave first arrival; a complex wave train consisting of higher mode Rayleigh waves; a precursor to air-blast wave; the air blast wave; and the air-coupled Rayleigh waves. Records from the second site, overlying an unlayered mass of igneous rocks, show only three distinct seismic phases: the P-wave first arrival; a simple wave train of fundamental-mode Rayleigh and Love waves; and an air blast wave. Peak ground velocity, based on the average of the three largest amplitudes in the surface waves preceding the air blast wave, scales well with yield for both sites. Measurements of peak ground velocity may be used to estimate yields of explosive charges at either site within a factor of about 2 if the source distance is known. The scaling relationship appears to be valid over a wide range of yields and site geological conditions.

scholarly journals A new pest management research facility Scions largescale precision track sprayer

2014 ◽  
Vol 67 ◽  
pp. 267-273
Author(s):  
S.F. Gous ◽  
T.M. Withers ◽  
A.J. Hewitt
Keyword(s):  
Large Scale ◽  
Spray Deposition ◽  
Management Research ◽  
Application Research ◽  
Pesticide Application ◽  
Research Facility ◽  
Liquid Pressure ◽  
Plant Canopies ◽  
Wide Range ◽  
Potential Use

A new large scale precision track sprayer has been developed and evaluated for spray deposition and pesticide application research under controlled conditions The spray room is fitted with a 4 m wide electrically driven boom suspended 4 m above ground running on a 12 m long Ibeam It is fitted with 9 independently controlled shut off valves and nozzles Sprays can be applied to live plant canopies up to 3 m tall within a 2 m times; 3 m sample area The number location and type of nozzle on the boom can be altered as can spray liquid pressure and boom speed in order to simulate a wide range of spray application scenarios Calibration of the largescale precision track sprayer has been undertaken for a range of droplet spectra from extremely coarse to very fine This paper documents the calibration results and discusses the potential use of this facility for pesticide application research

scholarly journals Performance and profitability of rain-based thresholds for timing fungicide applications in soybean rust control

2020 ◽  
Author(s):  
Gustavo C. Beruski ◽  
Emerson Medeiros Del Ponte ◽  
André B. Pereira ◽  
Mark L. Gleason ◽  
Gil M. S. Câmara ◽  
...  
Keyword(s):  
Disease Severity ◽  
Disease Risk ◽  
Climatic Conditions ◽  
Soybean Rust ◽  
Yield Data ◽  
Growing Seasons ◽  
Action Threshold ◽  
Temperature Thresholds ◽  
Fungicide Mixtures ◽  
Control Disease

AbstractSoybean rust (SBR), caused by the fungus Phakopsora pachyrhizi, is the most damaging disease of soybean in Brazil. Effective management is achieved by means of calendar-timed sprays of fungicide mixtures, which do not explicitly consider weather-associated disease risk. Two rainfall-based action thresholds of Disease Severity Values (DSV50 and DSV80) were proposed and compared with two leaf wetness duration-temperature thresholds of Daily Values of Infection Probability (DVIP6 and DVIP9) and with a calendar (CAL) program, with regards to performance and profitability. An unsprayed check treatment plot was included for calculating relative control. Disease severity and yield data were obtained from 29 experiments conducted at six sites across four states in Brazil during 2012-13, 2014-15 and 2015-16 growing seasons, which represented different growing regions and climatic conditions. The less conservative rainfall action threshold (DSV80) resulted in fewer fungicide sprays compared with the other treatments and the more conservative one (DSV50) resulted in fewer sprays than the DVIP thresholds. Yield was generally higher with the increase of spray number, but the economic analysis showed no significant differences on the risk of not offsetting the costs of fungicide sprays regardless of the system. Therefore, based on the simplicity and the profitability of the rain-based model, the system is a good candidate for incorporating into management of SBR in soybean production fields in Brazil.

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