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Droplet-Size Effects on Control of Chloris spp. with Six POST Herbicides

Published online by Cambridge University Press:  15 January 2019

J. Connor Ferguson*
Assistant Professor, Department of Plant and Soil Sciences, Mississippi State University, Mississippi State, MS, USA
Bhagirath S. Chauhan
Associate Professor, Queensland Alliance for Agriculture and Food Innovation (QAAFI), University of Queensland, Toowoomba, QLD, Australia
Rodolfo G. Chechetto
Researcher, AgroEfetiva Serviços SS Ltda, Botucatu, São Paulo, SP, Brazil
Andrew J. Hewitt
Senior Research Fellow, School of Agriculture and Food Sciences, University of Queensland, Gatton, QLD, Australia
Steve W. Adkins
Professor, School of Agriculture and Food Sciences, University of Queensland, Gatton, QLD, Australia
Greg R. Kruger
Weed Science and Application Technology Specialist, University of Nebraska–Lincoln, North Platte, NE, USA
Chris C. O’Donnell
Research Fellow, School of Agriculture and Food Sciences, University of Queensland, Gatton, QLD, Australia
Author for correspondence: J. Connor Ferguson, Department of Plant and Soil Sciences, Mississippi State University, 117 Dorman Hall, Mississippi State, MS 39762. (Email:


Chloris spp. are warm-season grasses that outcompete crops for scarce resources throughout Australia. In Queensland, mild winters and increased adoption of conservation tillage practices have led to an increase of this warm-season grass family in winter crops. The objective of this study is to understand whether droplet size (nozzle type) effects herbicide efficacy of summer perennial grasses, as previous research found no effect of droplet size (nozzle type) on herbicide efficacy of winter annual grasses. A study to compare droplet-size (nozzle type) effects on control of windmillgrass and its domesticated relative, rhodesgrass, was conducted at the University of Queensland in Gatton, QLD, Australia. Results showed little difference in dry weight reductions for windmillgrass or rhodesgrass across droplet size (nozzle type). Paraquat applications with the TTI nozzle resulted in significantly lower dry weight reductions compared with other droplet-size sprays (nozzle types) for rhodesgrass. Glyphosate, imazamox plus imazapyr, and clodinafop resulted in commercially acceptable control for both species, regardless of the droplet size (nozzle type) selected, indicating droplet size (nozzle type) has relatively little impact on the efficacy of these herbicides. Proper nozzle selection can result in control of Chloris spp., a hard to control weed species, while reducing the occurrence of spray drift to nearby sensitive areas.

Research Article
© Weed Science Society of America, 2019. 

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Cite this article: Ferguson JC, Chauhan BS, Chechetto RG, Hewitt AJ, Adkins SW, Kruger GR, O’Donnell CC (2019) Droplet-size effects on control of Chloris spp. with six POST herbicides. Weed Technol 33:153–158. doi: 10.1017/wet.2018.99


[ASAE] American Society of Agricultural and Biological Engineers (2009) Spray Nozzle Classification by Droplet Spectra. Standard 572.1. St Joseph, MI: American Society of Agricultural and Biological EngineersGoogle Scholar
[ABARES] Australian Bureau of Agricultural and Resource Economics and Sciences (2012) Agricultural Yearbook 2012. Accessed: November 12, 2015Google Scholar
Borger, J, Ferris, D (2013) Tolerance of Subtropical Grasses to In-Crop Selective Herbicides during Winter. GRDC Crop Updates Western Australia. 3 p.,_John_et_al_Tolerance_of_subtropical_grasses_to_in-crop_grass. Accessed: November 14, 2015Google Scholar
Borger, CPD, Reithmuller, G, Hashem, A (2009) Control of windmillgrass over the summer fallow increase wheat yield. Pages 48–51 in Zydenbos SM, ed., Proceedings of the 17th Australasian Weeds Conference. Christchurch, NZ: New Zealand Plant Protection SocietyGoogle Scholar
Byass, JB, Lake, JR (1977) Spray drift from a tractor-powered field sprayer. Pestic Sci 8:117126Google Scholar
Cook, T (2014) The Northern Grains Region: its unique herbicide resistance challenges. Pages 308–311 in Baker M, ed., Proceedings of the 19th Australasian Weed Conference. Hobart, TAS: Tasmanian Weed SocietyGoogle Scholar
Cook, T, Brooke, G, Street, M, Widderick, M (2014) Herbicides and Weeds—Regional Issues, Trials and Developments. GRDC Crop Updates Goondiwindi 2014. Accessed: November 12, 2015Google Scholar
Dorr, GJ, Hewitt, AJ, Adkins, SW, Hanan, J, Zhang, H, Noller, BA (2013) Comparison of initial spray characteristics produced by agricultural nozzles. Crop Prot 53:109117Google Scholar
[EPA] U.S. Environmental Protection Agency (1999) Spray drift on pesticides. EPA Publication No. 735 F99024. Washington, DC: U.S. Environmental Protection AgencyGoogle Scholar
[FAO] Food and Agricultural Organization of the United Nations (2011) FAO STAT Comparison of Wheat Area of Australia to the Rest of the World. Accessed: November 12, 2015Google Scholar
Felton, WL, Wicks, GA, Welsby, SM (1994) A survey of fallow practices and weed floras in wheat stubble and grain sorghum in northern New South Wales. Aust J Exp Agri 34:22236Google Scholar
Ferguson, JC, Chechetto, RG, Adkins, SW, Hewitt, AJ, Chauhan, BS, Kruger, GR, O’Donnell, CC (2018). Effect of spray droplet size on herbicide efficacy on four winter annual grasses. Crop Prot 112:118124Google Scholar
Ferguson, JC, Chechetto, RG, Hewitt, AJ, Chauhan, BS, Adkins, SW, Kruger, GR, O’Donnell, CC (2016a) Assessing the deposition and canopy penetration of nozzles with different spray qualities in an oat (Avena sativa L.) canopy. Crop Prot 81:1419Google Scholar
Ferguson, JC, Chechetto, RG, O’Donnell, CC, Dorr, GJ, Moore, JH, Baker, GJ, Powis, KJ, Hewitt, AJ (2016b) Determining the drift potentials of Venturi nozzles compared to standard nozzles across three insecticide spray solutions in a wind tunnel. Pest Manag Sci 72:14601466Google Scholar
Ferguson, JC, O’Donnell, CC, Chauhan, BS, Adkins, SW, Kruger, GR, Wang, R, Urach Ferreira, P, Hewitt, AJ (2015) Determining the uniformity and consistency of droplet size across spray drift reducing nozzles in a wind tunnel. Crop Prot 76:16Google Scholar
Grover, R, Kerr, LA, Maybank, J, Yoshida, K (1978) Field measurements of droplet drift from ground sprayers. Can J Plant Sci 58:611622Google Scholar
Hennigh, DS, Al-Khatib, K, Stahlman, PW, Shoup, DE (2005) Prairie cupgrass (Erichloa contract) and windmillgrass (Chloris verticillata) response to glyphosate and acetyl-CoA carboxylase-inhibiting herbicides. Weed Sci 53:31532210.1614/WS-04-112RGoogle Scholar
Hewitt, AJ (1997) The importance of droplet size in agricultural spraying. Atomization Sprays 7:235244Google Scholar
Kenward, MG, Roger, JH (1997) Small sample interference for fixed effects from restricted maximum likelihood. Biometrics 53:98399710.2307/2533558Google Scholar
Lamp, C, Forbes, S, Cade, J (2001) Grasses of Temperate Australia—A Field Guide. Melbourne, VIC, Australia: Blooming Books. 310 pGoogle Scholar
Michael, PJ, Borger, CP, MacLeod, WJ, Payne, PL (2010) Occurrence of summer fallow weeds within the grain belt region of southwestern Australia. Weed Technol 24:56256810.1614/WT-D-09-00060.1Google Scholar
Milford, R, Minson, DJ (1968) The digestibility and intake of six varieties of Rhodes grass (Chloris gayana). Aust J Exp Agric Anim Husb 8:413418Google Scholar
Mueller, TC, Womac, AR (1997) Effect of formulation and nozzle type on droplet size with isopropylamine and trimesium salts of glyphosate. Weed Technol 11:639643Google Scholar
Patra, J, Lenka, M, Panda, BB (1994) Tolerance and co-tolerance of the grass Chloris barbata Sw. to mercury, cadmium and zinc. New Phytol 128:165171Google Scholar
Peltzer, SC, Hashem, A, Osten, VA, Gupta, ML, Diggle, AJ, Reithmuller, GP, Douglas, A, Moore, JA, Koetz, EA (2009) Weed management in wide-row cropping systems: a review of current practices and risks for Australian farming systems. Crop Pasture Sci 60:395406Google Scholar
Sidak, Z (1967) Rectangular confidence regions for the means of multivariate normal distributions. J Am Stat Soc 62:626633Google Scholar
Southcombe, ESE, Miller, PCH, Ganzelmeier, H, Van de Zande, JC, Miralles, A, Hewitt, AJ (1997) The International (BCPC) Spray Classification System Including a Drift Potential Factor. Pages 371–380 in Proceedings of the Brighton Crop Protection Conference—Weeds. Brighton, UK: Brighton Crop Protection ConferenceGoogle Scholar
Stobbs, TH (1973) The effect of plant structure on the intake of tropical pastures. II Differences in sward structure, nutritive value, and bite size of animals grazing Setaria anceps and Chloris gayana at various stages of growth. Aust J Agric Res 24:82182910.1071/AR9730821Google Scholar
Syme, H, Botwright Acuña, TL, Abrecht, D, Wade, LJ (2007) Nitrogen contributions in a windmill grass (Chloris truncata) wheat (Triticum aestivum L.) system in south-western Australia. Aust J Soil Res 45:635642Google Scholar
Uk, S (1977) Tracing insecticide spray droplets by sizes on natural surfaces. The state of the art and its value. Pestic Sci 8:501509Google Scholar
Wicks, GA, Felton, WL, Murison, RD, Martin, RJ (2000) Changes in fallow weed species in continuous wheat in northern New South Wales 1981–1990. Aust J Exp Agri 40:831842Google Scholar
Yang, CW, Zhang, ML, Liu, J, Shi, DC, Wang, DL (2009) Effects of buffer capacity on growth, photosynthesis, and solute accumulation of a glycophyte (wheat) and a halophyte (Chloris virgata) Phytosynthetica 47:5560Google Scholar