Effects of Application Variables on Glyphosate Phytotoxicity

1987 ◽  
Vol 1 (1) ◽  
pp. 14-17 ◽  
Author(s):  
Douglas D. Buhler ◽  
Orvin C. Burnside

Glyphosate [N-(phosphonomethyl)glycine] toxicity to volunteer wheat (Triticum aestivumL.) and large crabgrass [Digitaria sanguinalis(L.) Scop. # DIGSA] was influenced more by carrier volume than application method. Glyphosate phytotoxicity increased when carrier volume was reduced with both application methods. When compared at equal carrier volumes, there was little difference in volunteer wheat or large crabgrass control when glyphosate was applied with a controlled droplet applicator or flat fan nozzles. Volunteer wheat and large crabgrass control with controlled droplet applicators was influenced by application factors. At a given carrier volume, application factors which yielded larger droplets generally resulted in superior vegetation control.

1989 ◽  
Vol 3 (1) ◽  
pp. 105-109 ◽  
Author(s):  
Reid J. Smeda ◽  
Alan R. Putnam

Foliar activity of the butyl ester of fluazifop on large crabgrass was determined by varying the concentration of a petroleum-based oil concentrate and the carrier volume. Increasing the concentration of petroleum oil or reducing the carrier volume improved large crabgrass control. Under greenhouse conditions, both visible injury and plant dry weight reflected greater control with adjuvant concentrations increasing from 0.62 to 5.0% v/v. Similarly, reducing carrier volumes from 374 to 47 L/ha increased grass control. No significant interaction between carrier volume and adjuvant concentration suggests the effects of these two variables are independent of one another. For both variables, effects were greater with sublethal rates of fluazifop.


2021 ◽  
pp. 1-24
Author(s):  
Benjamin P. Sperry ◽  
Jason A. Ferrell

Mesocosm studies were conducted in 2020 to evaluate the effects of carrier volume and application method on waterhyacinth response to 2,4-D, glyphosate, and diquat. Carrier volumes of 935, 467, and 187 L ha-1 were applied using either a conventional stream, conventional cone, adjustable cone, or a drizzle stream spray pattern. Reducing carrier volume from 935 L ha-1 reduced spray coverage up to 60% depending on application method. However, reducing carrier volume did not diminish efficacy of any herbicide or application method. Alternatively, waterhyacinth control from 2,4-D increased 10 to 26% when applied using 187 L ha-1 compared to 935 L ha-1. Likewise, waterhyacinth biomass was reduced 91% when 2,4-D was applied using 935 L ha-1; however, treatment applied at 187 L ha-1 resulted in 99% biomass reduction. In general, 2,4-D resulted in roughly 10% greater control when conventional or adjustable cone applications were used compared to either stream applications. Waterhyacinth control 7 days after treatment (DAT) from diquat increased with decreasing carrier volumes; however, treatment effects in diquat experiments were not detected at other evaluation intervals. Glyphosate efficacy was highly influenced by carrier volume as waterhyacinth control increased up to 61% when applied using 187 L ha-1 compared to 935 L ha-1. Moreover, waterhyacinth biomass reduction increased from 55% in 935 L ha-1 treatment to 97% in 187 L ha-1 treatments. Glyphosate application methods consisting of conventional stream or conventional cone sprayers resulted in slightly increased waterhyacinth control by 28 DAT; however, no differences among application methods were observed in waterhyacinth biomass data. These data support further evaluations of alternative application techniques for waterhyacinth control under field conditions as well as other herbicides and aquatic plant species.


Weed Science ◽  
1987 ◽  
Vol 35 (3) ◽  
pp. 412-417 ◽  
Author(s):  
Douglas D. Buhler

Weed control in reduced-tillage corn (Zea maysL. ‘Pioneer 3732′) with butylate [S-ethyl bis(2-methylpropyl) carbamothioate] and EPTC (S-ethyl dipropyl carbarnothioate) was not reduced when these herbicides were applied jointly with dry or liquid fertilizer. In most cases, application with fertilizer resulted in weed control similar to that observed when the herbicide was applied in water at 285 L/ha. Butylate applied as a granular formulation also gave weed control similar to the spray at 285 L/ha. Application in 95 L/ha of water consistently resulted in reduced weed control. Corn injury was not greatly influenced by application method, and differences in corn yield appeared to be due to differences in weed control. Growth chamber bioassays indicated that both butylate and EPTC dissipated more rapidly when applied in 95 L/ha of water than the other application methods, which may explain differences in weed control observed in the field.


Weed Science ◽  
2009 ◽  
Vol 57 (1) ◽  
pp. 1-5 ◽  
Author(s):  
Wesley J. Everman ◽  
Cassandra R. Mayhew ◽  
James D. Burton ◽  
Alan C. York ◽  
John W. Wilcut

Greenhouse studies were conducted to evaluate14C-glufosinate absorption, translocation, and metabolism in glufosinate-resistant corn, goosegrass, large crabgrass, and sicklepod. Glufosinate-resistant corn plants were treated at the four-leaf stage, whereas goosegrass, large crabgrass, and sicklepod were treated at 5, 7.5, and 10 cm, respectively. All plants were harvested at 1, 6, 24, 48, and 72 h after treatment (HAT). Absorption was less than 20% at all harvest intervals for glufosinate-resistant corn, whereas absorption in goosegrass and large crabgrass increased from approximately 20% 1 HAT to 50 and 76%, respectively, 72 HAT. Absorption of14C-glufosinate was greater than 90% 24 HAT in sicklepod. Significant levels of translocation were observed in glufosinate-resistant corn, with14C-glufosinate translocated to the region above the treated leaf and the roots up to 41 and 27%, respectively. No significant translocation was detected in any of the weed species at any harvest timing. Metabolites of14C-glufosinate were detected in glufosinate-resistant corn and all weed species. Seventy percent of14C was attributed to glufosinate metabolites 72 HAT in large crabgrass. Less metabolism was observed for sicklepod, goosegrass, and glufosinate-resistant corn, with metabolites composing less than 45% of detectable radioactivity 72 HAT.


2001 ◽  
Vol 28 (1) ◽  
pp. 28-33 ◽  
Author(s):  
J. P. Damicone ◽  
K. E. Jackson

Abstract Two trials with iprodione and three trials with fluazinam were conducted to assess the effects of application method and rate on the control of Sclerotinia blight of peanut with fungicide. In order to concentrate the fungicides near the crown area where the disease causes the most damage, applications were made through a canopy opener with a single nozzle centered over the row to achieve a 30.5-cm-wide band (canopy opener), and through a single nozzle centered over the row to achieve a 46-cm-wide band (band). Broadcast applications were compared to these methods at rates of 0, 0.28, 0.56, and 1.12 kg/ha on the susceptible cultivar Okrun. Sclerotinia blight was severe, with > 70% disease incidence and < 2000 kg/ha yield for the untreated controls in each trial. Linear reductions in area under the disease progress curve (AUDPC), but not final disease incidence, with iprodione rate were significant (P < 0.05) for all methods of application. However, the rate of decrease did not differ among application methods. Linear increases in yield with rate of iprodione were greater for canopy opener compared to the band or broadcast applications. Only a 50% reduction in AUDPC and a maximum yield of < 2700 kg/ha was achieved with iprodione using the best method. At the maximum rate of 1.12 kg/ha, fluazinam provided > 75% disease control and > 4000 kg/ha yield for all application methods. Differences in disease control and yield among application methods only occurred at the 0.28 and 0.56 kg/ha rates of fluazinam. Reductions in AUDPC with fluazinam rate were quadratic for all application methods, but AUDPC values were less for the canopy opener and band methods at 0.28 and 0.56 kg/ha compared to the broadcast methods. The yield response to rate for broadcast applications of fluazinam was linear. However, predicted yield responses to fluazinam rate were quadratic for the band and canopy opener methods and approached the maximum response at 0.84 kg/ha. Targeting fungicide applications using the band and/or canopy opener methods was beneficial for fluazinam at reduced rates. Disease control with iprodione was not adequate regardless of application method.


Weed Science ◽  
1986 ◽  
Vol 34 (4) ◽  
pp. 520-524 ◽  
Author(s):  
John R. Teasdale ◽  
Ray B. Taylorson

Methyl isothiocyanate (MIT) consistently killed large crabgrass [Digitaria sanguinalis(L.) Scop. # DIGSA] seed at concentations of 4.0 mM or greater. Concentrations of 0.6 to 1.0 mM MIT delayed germination of large crabgrass seed but ultimately allowed the majority of seed to germinate. Dormant large crabgrass seed were killed at concentrations of MIT similar to those required to kill nondormant seed. MIT stimulated germination of dormant large crabgrass seed at sublethal concentrations (0.1 to 1.0 mM). Experiments with metham (sodium methyldithiocarbamate) in the greenhouse and field (metham rapidly degrades to MIT in soils) confirmed results of laboratory experiments with MIT.


1995 ◽  
Vol 9 (4) ◽  
pp. 716-723 ◽  
Author(s):  
B. Jack Johnson ◽  
Robert N. Carrow

A field experiment was conducted over a 2-yr period to determine the effects of reduced PRE herbicide rates on large crabgrass infestation in six tall fescue cultivars. With the exception of oryzalin and benefin plus oryzalin in 1993, there was no cultivar by herbicide interaction for large crabgrass infestation when final ratings were made in 1993 and 1994. This interaction was caused by moderate to severe turfgrass injury that thinned the turf. When cultivars were disregarded, prodiamine was the only herbicide applied at one-third recommended rate in 1993 that effectively suppressed large crabgrass for the full season. Prodiamine and dithiopyr were the only PRE herbicides applied at one-third recommended rates for two consecutive years that effectively suppressed large crabgrass in 1994. Two-thirds recommended rate was needed for two consecutive years for oxadiazon, pendimethalin, oryzalin, benefin plus oryzalin, and benefin plus trifluralin to maintain optimum large crabgrass suppression in 1994.


2018 ◽  
Vol 36 (4) ◽  
pp. 133-139
Author(s):  
Cody J. Stewart ◽  
S. Christopher Marble ◽  
Brian E. Jackson ◽  
Brian J. Pearson ◽  
P. Christopher Wilson

Abstract Research objectives were to determine the effect of fertilization method (incorporation, subdress, and topdress) on weed growth and the performance of preemergence herbicides applied to soilless substrates. Nursery containers were filled with a pine bark:peat substrate and fertilized at two different rates [4.4 and 9.5 kg.m−3 (8.9 and 19.2 lb.yd−3)] via topdressing, subdressing, or incorporating. Containers were treated with either dimethenamid-P for spotted spurge (Euphorbia maculata L.), flumioxazin for eclipta (Eclipta prostrata L.) or prodiamine for large crabgrass (Digitaria sanguinalis L.). A control was established for each fertilizer rate/placement and weed species that was not treated. Incorporating or subdressing fertilizer resulted in reduced large crabgrass and spotted spurge growth in non-treated containers. Weeds grew larger at the higher fertility rates in both topdress and incorporated treatments but fertilizer rate did not affect growth of spotted spurge or large crabgrass when fertilizers were subdressed. Herbicides generally provided commercially acceptable weed control regardless of fertilizer treatment, but results varied with species. Results suggest that in the absence of herbicides, topdressing may result in greater weed growth compared with subdressing or incorporating fertilizers; however, fertilizer placement will have less impact on herbicide performance if proper herbicides are chosen and applied correctly. Index words: topdress, subdress, incorporate, large crabgrass, eclipta, spotted spurge, preemergence Chemicals used in this study: Flumioxazin (SureGuard®); 2-[7-fluoro-3,4-dihydro-3-oxo-4-(2-propynyl)-2H-1,4-benzoxazin-6-yl]-4,5,6,7-tetrahydro-1H-isoindole1,3(2H)-dione; Dimethenamid-P (Tower) 2-chloro-N-[(2,4-dimethyl-3-thienyl)-N-(2-methoxy-1-methylethyl)acetamide; Prodiamine (Barricade) 2,4-dinitro-N3, N3-dipropyl-6-(trifluoromethyl)-1,3-benzenediamine (Barricade®) Species used in this study: Large crabgrass (Digitaria sanguinalis L.); Eclipta (Eclipta prostrata L.); Spotted spurge (Euphorbia maculata L.)


Weed Science ◽  
1976 ◽  
Vol 24 (4) ◽  
pp. 422-424 ◽  
Author(s):  
B. J. Johnson

Six herbicides were applied monthly from February to May for control of large crabgrass [Digitaria sanguinalis (L.) Scop.] and goosegrass [Eleusine indica (L.) Gaertn.]. Bensulide [O,O-diisopropyl phosphorodithioate S-ester with N-(2-mercaptoethyl)benzenesulfonamide] applied in February or March controlled at least 70% of large crabgrass, whereas, treatments applied in April resulted in similar control at two of three locations. All herbicides failed to control large crabgrass when applied in May. Oxadiazon [2-tert-butyl-4(2,4-dichloro-5-isopropoxyphenyl)-δ2-1,3,4-oxadiazolin-5-one] and butralin [4-(1,1-dimethylethyl)-N-(1-methylpropyl)-2,6-dinitrobenzenamide] controlled goosegrass for the full season when applied in March or April. Oxadiazon also controlled goosegrass when applied in May.


1999 ◽  
Vol 13 (2) ◽  
pp. 253-256 ◽  
Author(s):  
Zachary J. Reicher ◽  
Daniel V. Weisenberger ◽  
Clark S. Throssell

There are limited options for controlling large crabgrass in spring-seeded cool-season turf. The objective of this experiment was to evaluate the safety and effectiveness of dithiopyr and quinclorac to control large crabgrass in spring-seeded Kentucky bluegrass and perennial ryegrass stands. Quinclorac at 0.84 kg/ha and dithiopyr at 0.56 kg/ha were applied separately at various times prior to seeding and after emergence of Kentucky bluegrass and perennial ryegrass. Quinclorac applied once at 2, 4, 8, or 12 weeks after emergence (WAE) or split-applied preplant incorporated (PPI) + 12 WAE will give season-long control of large crabgrass with no injury to spring-seeded Kentucky bluegrass or perennial ryegrass. Quinclorac applied PPI or 0 WAE is safe to use in spring seedings, but it will not provide season-long control of large crabgrass. Dithiopyr applied 2 or 4 WAE will control large crabgrass season-long while not injuring spring-seeded Kentucky bluegrass or perennial ryegrass. However, dithiopyr applied PPI or 0 WAE will severely limit germination of desirable turf, and dithiopyr applied 8 or 12 WAE will not control mature crabgrass.


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