Effects of wind direction, wind speed and travel speed on spray deposition

Nordbo, Ebbe; Kristensen, Kai; Kirknel, Erik

doi:10.1002/ps.2780380106

Cited by 20 publications

(8 citation statements)

References 21 publications

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“…the coarseness of droplets, and higher retention efficiency was consistently demonstrated with finer-droplet sprays. Increasing travel speed may improve spray collection on more vertical surfaces (Nordbo et al 1993), but this effect was not found significant in this study. The speeds used in this study may be too slow, and a track sprayer with a wider range of speed choices (Wolf et al 2000) may help determine this effect more accurately.…”

Section: Resultscontrasting

confidence: 60%

Spray Retention on Green Foxtail (Setaria viridis) and its Effect on Weed Control Efficacy by Pyricularia setariae¹

Peng¹,

Wolf²,

Byer³

et al. 2005

Weed Technology

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The importance of spray retention to the biocontrol of green foxtail with Pyricularia setariae was characterized using airbrush and broadcast sprayers at variable application volumes. Spray retention was determined by measuring amounts of a tracer dye solution on treated plants using fluorescence spectrophotometry. Depending on the droplet size, broadcast spraying at 1,000 to 2,000 L/ha produced a level of retention equivalent to that of airbrush spraying until runoff. The trend of P. setariae spore retention on green foxtail was similar to that of liquid retention. Broadcasting P. setariae at volumes producing equivalent spray retention to that of airbrush inoculation resulted in a similar level of weed control under greenhouse conditions. Reducing broadcast volume from 2,000 to 250 L/ha lowered biocontrol efficacy only slightly, when the concentration of P. setariae was increased proportionally to keep the applied fungal dose the same. A nozzle with a fine droplet spectrum (volume median diameter [VMD] 207 μm) had a significantly greater retention efficiency than a coarse spray (VMD 325 μm), but this retention difference was not translated into consistent enhancement of biocontrol efficacy. Higher retention increases may be necessary for more substantial improvement in biocontrol of green foxtail by P. setariae.

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Section: Resultscontrasting

confidence: 60%

Spray Retention on Green Foxtail (Setaria viridis) and its Effect on Weed Control Efficacy by Pyricularia setariae¹

Peng¹,

Wolf²,

Byer³

et al. 2005

Weed Technology

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“…It is not entirely clear why the youngest leaf was consistently less diseased. This emerging leaf is more vertically positioned, conceivably retaining less spray (Nordbo et al 1993). However, a separate study found that the retention was not significantly different among leaves of different positions, suggesting an equivalent amount of pathogen inoculum on all leaves (Peng et al 2001).…”

Section: Effect Of Weed Growth Stage On Biocontrol Efficacymentioning

confidence: 99%

Pyricularia setariae: a potential bioherbicide agent for control of green foxtail (Setaria viridis)

Peng¹,

Byer

Bailey

2004

Weed sci.

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One hundred and thirty-three fungal isolates, pathogenic to green foxtail, were evaluated for weed control potential under controlled conditions. To determine weed control efficacy, these pathogens were applied as spore or mycelial suspensions at approximately 105propagules ml−1to green foxtail at the three-leaf stage. One week after inoculation, most isolates caused only minor injury to the plants, but 15 isolates caused 50 to 100% disease. Among the most efficacious isolates, only those ofPyricularia setariaeexhibited strong host specificity to the target weed, revealing no significant pathogenicity on 28 other plant species tested, including many important crops such as wheat, barley, and oat. On green foxtail leaves, conidia of this fungus germinated readily at 14, 20, and 26 C, but the process of germination and appressorial formation was more rapid at the higher temperatures. The fungus applied at the concentration of 105spores ml−1reduced weed fresh weight by 34% 7 d after the treatment when compared with controls, whereas a concentration of 107spores ml−1reduced fresh weight by 87%. This efficacy was comparable with that of the herbicide sethoxydim. When applied to the weed at the one- to four-leaf stages, the fungus reduced green foxtail fresh weight by more than 80%. Efficacy was slightly lower on plants at the five-leaf stage or older. On the green foxtail biotype resistant to the herbicide sethoxydim,P. setariaecaused 80% fresh weight reduction compared with untreated controls, as opposed to 17% achieved with the herbicide. At 20 C, the fungus required a minimum of 6-h dew period to initiate infection, but a 10-h dew period was needed to cause severe damage to green foxtail.

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“…As a result, many sprayers are now configured with their nozzles angled 30 to 45Њ forward to facilitate spray deposition. Faster travel speeds also impart more horizontal trajectories to the spray (Nordbo et al 1993). In notill, vertically oriented stubble canopies may, like grassy weeds, be preferentially targeted by forward-oriented spray trajectories, reducing spray penetration.…”

mentioning

confidence: 99%

Optimizing postemergence herbicide deposition and efficacy through application variables in no-till systems

Wolf¹,

Harrison

Hall

et al. 2000

Weed Science

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Laboratory experiments were conducted to determine the effects of application factors and standing Triticum aestivum stubble on herbicide spray deposition and efficacy in a simulated no-till environment. Spray deposition on weeds was reduced in the presence of stubble, and deposition losses on Amaranthus hybridus were greater than those on Setaria faberi. Spray penetration through stubble was significantly enhanced with electrostatic charging of a fine hydraulic spray. The combination of 45 kV electrostatic charge and 50 cm nozzle spacing produced maximum spray deposition on weeds and resulted in a 96% and 345% increase in deposition on A. hybridus and S. faberi, respectively, compared to the uncharged controls. Deposit reduction from standing stubble was greater at travel speeds of 16 km h−1 (36 to 52%) than 8 km h−1 (9 to 38%). On a dry weight and plant density basis, weeds retained more spray than was retained by stubble, yet stubble, at average densities, was capable of capturing 9 to 12% of total applied spray dose per unit area. Bounce studies of individual droplets of water or imazethapyr plus adjuvant mixture demonstrated that T. aestivum straw had a general affinity for all spray droplets, exhibiting no rebound even for 800-µm water droplets. Setaria faberi foliage exhibited poor retention of droplets: both 350- and 800-µm water droplets as well as 800-µm droplets of imazethapyr plus adjuvant mixture rebounded. Only 350-µm herbicide mixture droplets were retained by S. faberi. Amaranthus hybridus retained all droplets. In broadcast spraying, British Crop Protection Council “Medium” quality sprays were poorly retained by S. faberi compared to “Fine” sprays, whereas A. hybridus retained both sprays equally well. However, imazethapyr spray deposits resulting from coarser sprays were more efficacious on S. faberi than fine spray deposits, a difference that was not observed for A. hybridus.

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Effects of wind direction, wind speed and travel speed on spray deposition

Cited by 20 publications

References 21 publications

Spray Retention on Green Foxtail (Setaria viridis) and its Effect on Weed Control Efficacy by Pyricularia setariae¹

Spray Retention on Green Foxtail (Setaria viridis) and its Effect on Weed Control Efficacy by Pyricularia setariae¹

Pyricularia setariae: a potential bioherbicide agent for control of green foxtail (Setaria viridis)

Optimizing postemergence herbicide deposition and efficacy through application variables in no-till systems

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Effects of wind direction, wind speed and travel speed on spray deposition

Cited by 20 publications

References 21 publications

Spray Retention on Green Foxtail (Setaria viridis) and its Effect on Weed Control Efficacy by Pyricularia setariae1

Spray Retention on Green Foxtail (Setaria viridis) and its Effect on Weed Control Efficacy by Pyricularia setariae1

Pyricularia setariae: a potential bioherbicide agent for control of green foxtail (Setaria viridis)

Optimizing postemergence herbicide deposition and efficacy through application variables in no-till systems

Contact Info

Product

Resources

About

Spray Retention on Green Foxtail (Setaria viridis) and its Effect on Weed Control Efficacy by Pyricularia setariae¹

Spray Retention on Green Foxtail (Setaria viridis) and its Effect on Weed Control Efficacy by Pyricularia setariae¹