scholarly journals INFLUENCE OF DROPLET SIZE ON SPRAY DEPOSITION AND WEED CONTROL USING GLYPHOSATE

2021 ◽  
Vol 41 (4) ◽  
pp. 449-457
Author(s):  
Osmar G. T. M. Oliveira ◽  
Paulo R. M. Lopes ◽  
Carlos G. Raetano ◽  
Ronaldo C. Lima ◽  
Evandro P. Prado
Keyword(s):  
Weed Control ◽  
Droplet Size ◽  
Spray Deposition

Fading Activities of Herbicidal Droplets Amended with Emulsifiable Spray Adjuvants on Cucurbitaceous Leaves

2018 ◽  
Vol 61 (6) ◽  
pp. 1881-1888
Author(s):  
Jeng-Liang Lin ◽  
Heping Zhu
Keyword(s):  
Weed Control ◽  
Droplet Size ◽  
Spray Deposition ◽  
Herbicide Application ◽  
Spray Droplet ◽  
Coverage Area ◽  
Maximum Coverage ◽  
Fading Time ◽  
Selection Of ◽  
Spray Adjuvants

Abstract. Understanding reactions of surfactant-amended droplets on difficult-to-wet weed surfaces could help develop application strategies to increase herbicide efficacy. Behaviors of herbicidal droplets containing different emulsifiable anti-evaporation spray adjuvants were investigated by characterizing 250 and 450 µm herbicidal droplet dispersion and fading time on cucurbitaceous leaves placed inside a 20°C chamber at 30% and 60% relative humidity (RH). Droplet maximum coverage area increased with droplet size but not with RH, while droplet fading time increased with both droplet size and RH. Despite 450 µm droplets having greater maximum coverage area than 250 µm droplets, the larger droplets had higher fading rates and lower ratios of maximum coverage area to droplet volume. Droplet maximum coverage area and fading time on leaves were affected by adding spray adjuvants to the herbicide-only solution. The Uptake surfactant was more effective than the other two surfactants (AntiEvap+BS1000 and Enhance) in increasing droplet maximum coverage area and fading time. Compared to the herbicide-only solution, addition of Uptake surfactant to the herbicide solution could increase maximum coverage area by 68% and 52% for 250 and 450 µm droplets, respectively, but addition of AntiEvap+BS1000 or Enhance surfactants did not show significant increase. Similarly, addition of Uptake surfactant to the herbicide-only solution increased droplet fading times by 11.1% and 13.2% at 30% and 60% RH, respectively, for 250 µm droplets and by 34.7% and 2.8% at 30% and 60% RH, respectively, for 450 µm droplets. In contrast, addition of AntiEvap+BS1000 surfactant reduced fading time, and addition of Enhance surfactant did not significantly affect fading time. Therefore, appropriate selection of spray adjuvants for herbicide applications could significantly influence droplet deposit behaviors on cucurbitaceous leaves, leading to improved effectiveness of weed control. Keywords: Herbicide application, Spray deposition, Spray droplet, Surfactant, Weed control.

Effect of day time climatic conditions associated with different 2,4-D formulations on spray deposition and weed control

2019 ◽  
Vol 54 (10) ◽  
pp. 803-809
Author(s):  
Robinson L. Contiero ◽  
Fabiano A. Rios ◽  
Denis F. Biffe ◽  
Guilherme B. P. Braz ◽  
Jamil Constantin ◽  
...  
Keyword(s):  
Weed Control ◽  
Spray Deposition ◽  
Climatic Conditions

Effect of Formulation and Nozzle Type on Droplet Size with Isopropylamine and Trimesium Salts of Glyphosate

1997 ◽  
Vol 11 (4) ◽  
pp. 639-643 ◽  
Author(s):  
Thomas C. Mueller ◽  
Alvin R. Womac
Keyword(s):  
Nonionic Surfactant ◽  
Weed Control ◽  
Droplet Size ◽  
Management Tool ◽  
Spray Droplet ◽  
Droplet Distribution ◽  
Extended Range ◽  
Glyphosate Formulation ◽  
Nozzle Type ◽  
Flat Fan Nozzle

When spray mixtures were examined using a laser spray droplet analyzer, the new isopropylamine glyphosate formulation produced more small droplets than a previous isopropylamine salt of glyphosate formulation or glyphosate–trimesium plus nonionic surfactant. The use of a pre-orifice flat-fan nozzle and an impact type flat-fan nozzle reduced the amount of small droplets produced compared to an existing extended range flat-fan nozzle, while maintaining a spray droplet distribution that could still provide good weed control. The new nozzle technologies could provide a useful management tool to manage potential drift situations.

scholarly journals Spray deposition, adjuvants, and physiochemical properties affect benzobicyclon efficacy

2019 ◽  
Vol 33 (2) ◽  
pp. 258-262
Author(s):  
Chad Brabham ◽  
Jason K. Norsworthy ◽  
Craig A. Sandoski ◽  
Vijay K. Varanasi ◽  
Lauren M. Schwartz-Lazaro
Keyword(s):  
Weed Control ◽  
Spray Deposition ◽  
Herbicidal Activity ◽  
Weedy Rice ◽  
Complex Activity ◽  
Complete Control ◽  
Physiochemical Properties ◽  
Flood Water ◽  
Flooded Rice ◽  
Herbicide Activity

AbstractBenzobicyclon is a new pro-herbicide being evaluated in the Midsouth United States as a post-flood weed control option in rice. Applications of benzobicyclon to flooded rice are necessary for efficacious herbicide activity, but why this is so remains unknown. Two greenhouse experiments were conducted to explore how herbicide placement (foliage only, flood water only, foliage and flood water simultaneously) and adjuvants (nonionic surfactant, crop oil concentrate, and methylated seed oil [MSO]) affect herbicide activity. The first experiment focused on importance of herbicide placement. Little to no herbicidal activity (<18% visual control) was observed on two- to four-leaf barnyardgrass, Amazon sprangletop, and benzobicyclon-susceptible weedy rice with benzobicyclon treatments applied to weed foliage only. In contrast, applications made only to the flood water accounted for >82% of the weed control and biomass reduction achieved when benzobicyclon was applied to flood water and foliage simultaneously. The second experiment concentrated on adjuvant type and benzobicyclon efficacy when applied to foliage and flood water simultaneously. At 28 days after treatment, benzobicyclon alone at 371 g ai ha−1 provided 29% and 67% control of three- to five-leaf barnyardgrass and Amazon sprangletop, respectively. The inclusion of any adjuvant significantly increased control, with MSO providing near-complete control of barnyardgrass and Amazon sprangletop. Furthermore, we used the physiochemical properties of benzobicyclon and benzobicyclon hydrolysate to derive theories to explain the complex activity of benzobicyclon observed in our study and in field trials. Benzobicyclon applications should contain an oil-based adjuvant and must be applied to flooded rice fields for optimal activity.

Increased Carrier Volume Improves Preemergence Control of Rigid Ryegrass (Lolium rigidum) in Zero-Tillage Seeding Systems

2013 ◽  
Vol 27 (4) ◽  
pp. 649-655 ◽  
Author(s):  
Catherine P. D. Borger ◽  
Glen P. Riethmuller ◽  
Michael Ashworth ◽  
David Minkey ◽  
Abul Hashem ◽  
...  
Keyword(s):  
Weed Control ◽  
Droplet Size ◽  
Water Soluble ◽  
Zero Tillage ◽  
Tillage System ◽  
Quality Water ◽  
High Carrier ◽  
Rigid Ryegrass ◽  
Carrier Volume ◽  
The Impact

PRE herbicides are less effective in the zero-tillage system because of increased residual crop stubble and reduced soil incorporation. However, since weeds are not physically controlled in the zero-tillage system, reliance on efficacy of PRE herbicides is increased. This research investigated the impact of carrier volume and droplet size on the performance of PRE herbicides (in wheat crops at four sites in 2010) to improve herbicide efficacy in conditions of high stubble biomass in zero-tillage systems. Increasing carrier volume from 30 to 150 L ha−1increased spray coverage on water-sensitive paper from an average of 5 to 32%. Average control of rigid ryegrass by trifluralin (at Cunderdin and Merredin sites) and trifluralin or pyroxasulfone (at Wickepin and Esperance sites) improved from 53 to 78% with increasing carrier volume. Use of ASABE Medium droplet size improved spray coverage compared with ASABE Extremely Coarse droplet size, but did not affect herbicide performance. It is clear that increased carrier volume improves rigid ryegrass weed control for nonwater-soluble (trifluralin) and water-soluble (pyroxasulfone) PRE herbicides. Western Australian growers often use low carrier volumes to reduce time of spray application or because sufficient high-quality water is not available, but the advantages of improved weed control justifies the use of a high carrier volume in areas of high weed density.

Spray Tip Configurations with Pulse-Width Modulation for Glufosinate-Ammonium Deposits in Palmer Amaranth (Amaranthus palmeri)

2017 ◽  
Vol 60 (4) ◽  
pp. 1123-1136 ◽  
Author(s):  
Alvin Ray Womac ◽  
Galina Melnichenko ◽  
Larry Steckel ◽  
Garrett Montgomery ◽  
Julie Reeves ◽  
...  
Keyword(s):  
Droplet Size ◽  
Pulse Width ◽  
Pulse Width Modulation ◽  
Spray Deposition ◽  
Test Methods ◽  
Palmer Amaranth ◽  
Published Data ◽  
Current Experiment ◽  
Glufosinate Ammonium ◽  
Extended Range

Abstract. A commercial sprayer operated at a field speed of 24 km h-1 simultaneously applied glufosinate-ammonium through seven spray tip treatments spaced along a 30.5 m boom for measured foliar deposits of herbicide in 35 cm tall Palmer amaranth weeds and spray deposits on foliar-mounted water-sensitive paper (WSP). The experiment followed one that found increased herbicide deposits for dual tips with an adjacent, fore-aft mount, downward-pointed pre-orifice tip (Extremely Coarse) operated with blended pulse-width modulation (bPWM) and a pre-orifice tip (Fine) operated constant (non-bPWM) under moderate ambient wind velocities from 3.1 to 4.1 m s-1. Additional dual-tip treatments were added to the dual-tip configuration for the current experiment to expand droplet Coarseness and to add dual tips operated constant to isolate bPWM effects. Tested treatments in common with the previous experiment included the original dual-tip bPWM and non-bPWM combination, Y-adapter fore-aft-mounted pre-orifice tips with diverging spray patterns both operated bPWM, and an air-induction extended-range tip operated constant. Palmer amaranth weeds, total spray volume rate of 93.5 L ha-1, sprayer speed of 24 km h-1, and test methods were similar between studies, except for negligible wind in the current experiment. Conditions were clear and sunny during spraying without indicators of a stable atmosphere. Overall mean glufosinate-ammonium deposits recovered from leaves were greatest for dual-tips operated constant at reduced droplet size (Very Coarse and Fine) due to reduced required tip size operated without bPWM, and for increased droplet size for Y-adapter-mounted pre-orifice tips (Extremely Coarse and Coarse) operated with bPWM, resulting in overall mean glufosinate-ammonium leaf deposits of 15.9 and 15.0 µg a.i. cm-2, respectively. The combination of dual tips at reduced droplet size or the Y-adapter fore-aft spray pattern divergence of bPWM tips coupled with high sprayer speed enhanced droplet interception by Palmer amaranth plants under negligible wind conditions, since the collected deposits, even without summed integration over foliage height, significantly exceeded the applied rate of 8.2 µg a.i. cm-2. An air-induction extended-range tip non-bPWM (Very Coarse) provided the next highest mean in overall glufosinate-ammonium deposit. One increased-droplet size dual-tip, pre-orifice tip bPWM and non-bPWM (Ultra Coarse and Coarse) resulted in a mean deposit that was not significantly different from the air-induction extended-range tip operated non-bPWM. Other dual-tip combinations with bPWM and non-bPWM, including the original dual-tip configuration in the previous study, resulted in significantly reduced mean herbicide deposits. Considering all tested tips, advantages of bPWM depended on spray tip droplet size classifications and Y-mounted fore-aft divergence of spray patterns. Overall mean WSP spot deposits were greatest for reduced droplet size (Very Coarse and Fine) dual pre-orifice tips operated non-bPWM, corresponding with the highest numerical overall mean of glufosinate-ammonium deposit. This correspondence of highest spot deposits and highest mean glufosinate-ammonium deposit also occurred in the previous study. Increased Palmer amaranth control correlated with increased glufosinate-ammonium deposit and decreased volume median diameter (Dv0.5) determined with WSP electronic scans, with the air-induction extended-range tip operated constant and the Y-adapter pre-orifice tip operated as bPWM providing the highest weed control. Overall mean WSP spot deposits ranged from 42.3 to 81.1 spots cm-2, compared to 14.0 to 47.0 spots cm-2 previously reported for similar spray conditions, with spot deposits attributed to negligible wind versus wind, respectively. Thus, the spray environment, particularly wind, exhibited effects on nozzle tip comparisons for foliar deposition and may offer some rationale for the conflicting published data beyond the examined treatments. Keywords: Application technology, Blended pulse-width modulation, Herbicide, Herbicide resistance, Nozzle, Spray deposition, Water-sensitive paper, Weed.

Developing the USDA ARS Spray Nozzle Models for Rotary Wing Applications

2017 ◽  
Vol 33 (5) ◽  
pp. 631-640
Author(s):  
W Clint Hoffmann ◽  
Bradley K Fritz
Keyword(s):  
Droplet Size ◽  
User Interfaces ◽  
Computational Models ◽  
Spray Deposition ◽  
Orientation Angle ◽  
Spray Drift ◽  
Product Label ◽  
Aerial Application ◽  
Nozzle Orifice ◽  
Rotary Wing

Abstract. Optimizing aerial spray applications requires proper setup of the sprayer system, particularly with respect to nozzle selection and operation, which significantly affects spray deposition, product efficacy, and spray drift. Droplet size from an aerial application is a function of the combination of nozzle type, nozzle orifice size, spray pressure, orientation angle, and airspeed of the aircraft. A set of computational models for 14 commonly-used aerial application nozzles were developed and released for use by applicators. These models allow applicators to determine the droplet size characteristics associated with their specific nozzle and operational setup, determining the proper combination of orifice, pressure, orientation, and airspeeds from 22 to 54 m/s (50 to 120 mph), which are commonly-associated with applications made from rotary wing aircraft (i.e., helicopters). Both spreadsheet and smartphone user interfaces are available for applicators to use to ensure that their application conforms to the legal droplet size requirements specified on an agrochemical product label. Keywords: Aerial application, Atomization, Droplet size, Droplet size models, Spray nozzles.

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