Effect of Application Timing on Rhizome Johnsongrass (Sorghum halepense) Control with DPX-V9360

Weed Science ◽  
1990 ◽  
Vol 38 (1) ◽  
pp. 45-49 ◽  
Author(s):  
Timothy T. Obrigawitch ◽  
William H. Kenyon ◽  
Henry Kuratle

Field, greenhouse, and laboratory studies were conducted to examine the effect of application timing on the activity of DPX-V9360 on rhizome johnsongrass. Field and greenhouse studies indicated that johnsongrass treated with postemergence applications of DPX-V9360 at late growth stages (>5 leaves) was controlled more effectively than when treated in early growth stages (<5 leaves). Johnsongrass control was optimized with split-postemergence applications (treatments applied at early and late growth stages) in field studies compared to a single postemergence application at either early or late growth stages. The pattern of translocation of 2-14C (pyrimidine)-labeled DPX-V9360 applied to a fully expanded johnsongrass leaf did not differ significantly between three different growth stages of 10-, 30-, and 60-cm height. Over 60% of the absorbed14C remained in the treated leaf. Most of the translocated14C moved out of the treated leaf within 3 days after application and distributed to the shoot in greater quantities than to the rhizomes. About 40% of14C-DPX-V9360 applied to the leaf surfaces of a tolerant species (corn) or susceptible species (johnsongrass) was absorbed into the leaf. Corn metabolized over 90% of absorbed DPX-V9360 within 20 h, while there was no perceptible metabolism of DPX-V9360 in johnsongrass leaves after 24 h. Late growth stage and split-postemergence applications appear to provide more effective control than early growth stage applications because of better control of regrowth (new shoot emergence from rhizomes after application) and because tillering and plant emergence are more nearly complete at application time.

2006 ◽  
Vol 20 (4) ◽  
pp. 992-998 ◽  
Author(s):  
Christos A. Damalas ◽  
Kico V. Dhima ◽  
Ilias G. Eleftherohorinos

Experiments were conducted to study the effect of application rate, growth stage, and tank-mixing azimsulfuron or bentazon on the activity of cyhalofop, clefoxydim, and penoxsulam against two morphologically distinctEchinochloaspecies from rice fields in Greece. Mixtures of penoxsulam with MCPA were also evaluated. Cyhalofop (300 to 600 g ai/ha) applied at the three- to four-leaf growth stage provided 62 to 85% control of early watergrass but 41 to 83% control of late watergrass averaged over mixture treatments. Control ranged from 37 to 80% for early watergrass and from 35 to 78% for late watergrass when cyhalofop was applied at the five- to six-leaf growth stage averaged over mixture treatments. Mixtures of cyhalofop with azimsulfuron or bentazon reduced efficacy on both species irrespective of growth stage or cyhalofop application rate compared with cyhalofop alone. Clefoxydim (100 to 250 g ai/ha) applied alone at the three- to four-leaf growth stage provided 98 to 100% control of early watergrass and 91 to 100% control of late watergrass; when clefoxydim was applied alone at the five- to six-leaf growth stage the control obtained was 91 to 100% for early watergrass and 79 to 100% for late watergrass. Mixtures of clefoxydim with azimsulfuron or bentazon reduced efficacy on late watergrass at the early growth stage and on both species at the late growth stage. Penoxsulam (20 to 40 g ai/ha) applied alone provided 94 to 100% control of both species at both growth stages. Mixtures of MCPA with penoxsulam reduced efficacy on late watergrass at the early growth stage and on both species at the late growth stage. Mixtures of penoxsulam with azimsulfuron or bentazon reduced efficacy only on late watergrass at the late growth stage.


2007 ◽  
Vol 21 (1) ◽  
pp. 37-40 ◽  
Author(s):  
Robert J. Richardson ◽  
Henry P. Wilson ◽  
Gregory R. Armel ◽  
Thomas E. Hines

Field studies were conducted in 1999, 2000, and 2001 to evaluate cotton response to trifloxysulfuron applied postemergence over the top (POT) or postemergence-directed (PDIR) at various growth stages. Treatments included trifloxysulfuron at 3.8 or 7.5 g ai/ha plus nonionic surfactant (NIS) applied POT to one-, three-, and five-leaf cotton or applied PDIR to 30- and 45-cm tall cotton. Crop injury 7 d after treatment (DAT) varied by year and ranged from 17 to 50%, 19 to 46%, and 5 to 23% with trifloxysulfuron applied POT to one-, three-, and five-leaf cotton, respectively. Injury 21DAT averaged 22, 16, and 6% with one-, three-, and five-leaf applications respectively. Trifloxysulfuron applied PDIR injured cotton 2 to 9% 7 DAT and 0 to 12% 21 DAT. At 30 DAT, cotton height was reduced with one-leaf trifloxysulfuron application, whereas differences were not present across other treatments. Heights at 90 days after planting (DAP) did not differ between treatments. Neither trifloxysulfuron rate or application timing negatively affected cotton yield or fiber quality.


2004 ◽  
Vol 18 (3) ◽  
pp. 527-531 ◽  
Author(s):  
Jason K. Norsworthy

Field studies were conducted to determine the sensitivity of conventional ‘Motte’ and ‘Pioneer 9831’ soybean to simulated glyphosate drift rates applied during vegetative and reproductive development and the effect of glyphosate on progeny. Glyphosate at 8, 84, and 420 g ae/ha was applied to soybean at the V3, V6, R2, and R5 growth stages. Glyphosate at 8 and 84 g/ha did not reduce soybean plant population, growth, or yield or cause deleterious effects on progeny, regardless of the growth stage at application. Soybean population, growth, and yield were reduced as much as 99 to 100% after application of 420 g/ha glyphosate at the V3 growth stage. Glyphosate at 420 g/ha applied at V6 was less detrimental to soybean compared with the V3 timing. Delaying the application of 420 g/ha glyphosate until R2 and R5 reduced soybean yields 22 to 49% and 43 to 44%, respectively. Soybean injury from 420 g/ha glyphosate was generally transient or less severe when applied at the V6 growth stage or later. However, 420 g/ha glyphosate at R5 (initial podfill) caused a 390 to 450 kg/ha yield reduction compared with the V6 application, which indicated greater soybean vulnerability to glyphosate drift during podfill than in the late-stage vegetative development. Although glyphosate at 420 g/ha was injurious to soybean, regardless of application timing, progeny was not affected.


Weed Science ◽  
1997 ◽  
Vol 45 (4) ◽  
pp. 497-501 ◽  
Author(s):  
Shane E. Taylor ◽  
Lawrence R. Oliver

Field studies were conducted at the Main Experiment Station, Fayetteville, AR, in 1994 and 1995 to evaluate the effect of postemergence herbicides applied at late-season timings on sicklepod seed production and viability. AC 263,222, dicamba, glyphosate, glufosinate, and paraquat were applied at five rates (zero; labeled rate; one-half, one-fourth, and one-eighth the labeled rate) to three sicklepod growth stages (bud formation, flowering to 9-cm pods, and 15- to 30-cm pods). The greatest reduction in seed production occurred when herbicides were applied at the flowering to 9-cm pod growth stage. All herbicides applied at one-half the labeled rate to sicklepod at bud formation and at the flowering to 9-cm pod growth stage reduced seed production greater than 80%, except glufosinate. Regardless of herbicide, rate, or application timing, viability of remaining seed was ≥ 90% with all treatments.


Plants ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 284
Author(s):  
Jackline Abu-Nassar ◽  
Maor Matzrafi

Solanum rostratum Dunal is an invasive weed species that invaded Israel in the 1950s. The weed appears in several germination flashes, from early spring until late summer. Recently, an increase in its distribution range was observed, alongside the identification of new populations in the northern part of Israel. This study aimed to investigate the efficacy of herbicide application for the control of S. rostratum using two field populations originated from the Golan Heights and the Jezreel Valley. While minor differences in herbicide efficacy were recorded between populations, plant growth stage had a significant effect on herbicide response. Carfentrazone-ethyl was found to be highly effective in controlling plants at both early and late growth stages. Metribuzin, oxadiazon, oxyfluorfen and tembutrione showed reduced efficacy when applied at later growth stage (8–9 cm height), as compared to the application at an early growth stage (4–5 cm height). Tank mixes of oxadiazon and oxyfluorfen with different concentrations of surfactant improved later growth stage plant control. Taken together, our study highlights several herbicides that can improve weed control and may be used as chemical solutions alongside diversified crop rotation options. Thus, they may aid in preventing the spread and further buildup of S. rostratum field populations.


2011 ◽  
Vol 25 (2) ◽  
pp. 192-197 ◽  
Author(s):  
Jason A. Bond ◽  
Timothy W. Walker

Field studies were conducted to compare the response of one inbred (‘CL161’) and two hybrid (‘CLXL729’ and ‘CLXL745’) Clearfield (CL) rice cultivars to imazamox. Imazamox was applied at 44 and 88 g ai ha−1to rice in the panicle initiation (PI) and PI plus 14 d (PI + 14) growth stages and at 44 g ha−1to rice in the midboot growth stage. Maturity of hybrid CL cultivars was delayed following imazamox at 44 g ha−1applied at PI + 14 and midboot. Furthermore, imazamox at 44 g ha−1, applied at midboot, delayed maturity of CLXL745 more than CLXL729. Expressed as a percentage of the weed-free control plots, rough rice yields for CLXL729 were 91% following imazamox at 44 g ha−1applied at PI + 14, 78% following imazamox at 44 g ha−1applied at midboot, and 77% for imazamox at 88 g ha−1applied at PI + 14. Rough rice yield for CLXL745 was 77 to 92% of the control following all imazamox treatments. All imazamox treatments reduced CLXL745 rough rice yield compared with CL161. Rough rice yield, pooled across CL cultivar, varied with imazamox treatment between years, and these differences may have been a consequence of lower temperatures and solar radiation in the first year. Hybrid CL cultivars CLXL729 and CLXL745 were less tolerant than was CL161 when imazamox was applied at nonlabeled rates (88 g ha−1) and/or timings (PI + 14 or midboot). Because of variability in rice growth stages and irregularities in imazamox application in commercial fields, inbred CL cultivars should be planted where an imazamox application will likely be required.


HortScience ◽  
2018 ◽  
Vol 53 (6) ◽  
pp. 865-874 ◽  
Author(s):  
Thitipat Weeplian ◽  
Tsair-Bor Yen ◽  
Yunn-Shy Ho

To investigate the effects of light treatments on the growth morphology and chemical constituents of Mesembryanthemum crystallinum L. plants, red (R), blue (B), far red (Fr), and white (W) light-emitting diodes (LEDs) were configured to provide different combinations of light spectra and photosynthetic photon flux densities (PPFDs). In Expt. 1, five light spectra of red/white (RW), red/white/far red (RWFr), red/white/high-intensity far red (RWFrD), red/blue (RB), and red/blue/far red (RBFr) were set up in two 3-layered racks with circulating hydroponic systems. In each light spectrum treatment, the distance between the LED lamps and the transplanting board was regulated to provide low PPFD and high PPFD treatments. In Expt. 2, the effect of Fr was further investigated in plants in the early and late growth stages. RWFr light was modified by covering the Fr lamps to become red/white without far red (RW−Fr) light during the early growth stage, and then removing the covers to provide the Fr spectrum red/white with far red (RW+Fr) during the later growth stage. This study suggested that high PPFD was not beneficial for promoting plant growth in any light spectrum treatment. Among light spectrum treatments at a PPFD of 215 ± 15 μmol·m−2·s−1, RW light produced higher vegetative growth. In the late growth stage, RW and RB combined with Fr light promoted reproductive growth, antioxidant activities, and secondary compounds, such as phenolic compounds, pinitol accumulation, and betacyanins. Therefore, RW (227 μmol·m−2·s−1), RW−Fr (162 μmol·m−2·s−1), and RB (162 μmol·m−2·s−1) are suggested for the early growth stage to promote vegetative growth. Then additional Fr light can be applied in addition to RW for secondary metabolite induction in the late growth stage.


2011 ◽  
Vol 50 (No. 2) ◽  
pp. 88-94 ◽  
Author(s):  
J. Soukup ◽  
M. Jursík ◽  
P. Hamouz ◽  
J. Holec ◽  
J. Krupka

Pot trials and field studies were carried out to describe the influence of soil pH and rainfall on the phytotoxic effect of the herbicide Merlin 750 WG (isoxaflutole) in maize. Symptoms as bleaching, and root and shoot weight reduction in early growth of maize were found. In pot trials, a statistically significant crop injury in early growth of maize was found only at the herbicide dose of 100 and 130 g/ha followed by 30 mm precipitation directly after herbicide application in soils with pH 6.5 and 7.2. Bleaching and significant weight reduction of maize up to growth stage BBCH 13 were observed in field trials at treatments with early post-emergence application of Merlin and 20 mm precipitations. Bleaching symptoms recovered up to BBCH 19. Significant differences were found in maize shoot weight and cob yield between treatments with and without watering (20 mm irrigation), and between pre- and post-emergence application of Merlin under field conditions. No significant differences were found between herbicide doses tested.


1988 ◽  
Vol 116 ◽  
Author(s):  
Yoshihiro Morimoto ◽  
Shoichiro Matsumoto ◽  
Shoji Sudo ◽  
Kiyoshi Yoneda

AbstractWe report the first study on improvement in surface morphology and crystal quality of as—grown epitaxial CaF2 film on a (100) Si substrate grown through two MBE growth stages without any post-growth treatment. The degree of improvement in surfacemorphology and crystal quality depends not only on the thickness of an initial thin CaF2 film grown at the early growth stage of 550ºC but also on both the subsrate temperature and thickness of a sequential grown CaF2 film used for thesecond growth stage. Under optimum conditions, the CaF2 films exhibited high quality with an RBS/channeling minimum yield of 4%, together with a very smooth surface morphology without any other nuclel or cracks.


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