Efficacy of post-emergence herbicides for weed control in chemical fallows in southern Queensland

1990 ◽  
Vol 30 (1) ◽  
pp. 79
Author(s):  
VA Pope ◽  
PN McConville

Out-of-patent herbicides (2,4-D, MCPA, dichlorprop, amitrole, ametryn, atrazine and linuron) were screened at 3 rates of post-emergence application for weed control during fallow periods in southern Queensland. Herbicide efficacy was assessed on 26 weeds at 1 or more stages of growth. Each herbicide had a limited spectrum of activity over the range of species encountered, with amitrole being the most effective. The chlorophenoxy compounds controlled only some of the broad-leaved species and had no effect on grass species. Where more than 1 growth stage for each weed was encountered, differences in susceptibility to the herbicides were evident amongst stages. Most herbicides were ineffective on large weeds. The rate of herbicide application also influenced the level of activity on most species. Most of the weeds in the Brassicaceae group were susceptible to all rates of the chlorophenoxy herbicides.

2007 ◽  
Vol 21 (4) ◽  
pp. 997-1001 ◽  
Author(s):  
Derek M. Scroggs ◽  
Donnie K. Miller ◽  
James L. Griffin ◽  
Lawrence E. Steckel ◽  
David C. Blouin ◽  
...  

Field studies were conducted 2004 and 2005 to evaluate weed control following POST applications of glyphosate in combination with eitherS-metolachlor (premix formulation), pyrithiobac, or trifloxysulfuron in conjunction with glyphosate in second-generation glyphosate-resistant cotton (Roundup Ready Flex). These herbicides were applied in combination with glyphosate in a two-application program at the 2-leaf (LF) (followed by glyphosate alone at the 10-LF growth stage), 6-LF (following glyphosate alone at the 2-LF growth stage), or 10-LF (following glyphosate alone at the 2-LF growth stage) cotton growth stages. No differences in weed control between residual herbicide were observed for goosegrass, hemp sesbania, Johnsongrass, Palmer amaranth, redroot pigweed, sicklepod, or smellmelon. Optimum control of barnyardgrass and browntop millet was achieved with glyphosate plusS-metolachlor. No differences were observed among application timings for control of goosegrass, hemp sesbania, Johnsongrass, pitted morningglory, and smellmelon. Control of barnyardgrass, browntop millet, Palmer amaranth, redroot pigweed, and sicklepod was optimized with residual herbicide application at the 2- or 10-LF timing. No yield differences were observed between residual herbicides, and seed cotton yield averaged 2,800 kg/ha. Yield was maximized when residual herbicide was applied at the 2- or 10-LF growth stage (2,960 to 2,730 kg/ha). Analysis based on numerical yield at particular residual-herbicide application timings and calculated yield for each timing based on the percentage of a standard three-application glyphosate program indicated the most consistent residual-herbicide timing for optimizing yield in a reduced-input Roundup Ready Flex weed-control program occurred at the two-leaf growth stage. All reduced-input programs, however, resulted in cotton yield of at least 93% of that obtained with the standard program.


Plants ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 732
Author(s):  
Ana Pintar ◽  
Zlatko Svečnjak ◽  
Valentina Šoštarčić ◽  
Josip Lakić ◽  
Klara Barić ◽  
...  

Alopecurus myosuroides Huds. is an important pinoxaden-resistant grass weed in many countries of Europe. Recently, the low efficacy of pinoxaden was reported in winter cereals in Croatia, but a preliminary dose–response trial showed no herbicide resistance for the investigated weed population. Therefore, a two-year experiment was conducted under greenhouse conditions to determine the efficacy of various pinoxaden doses (20, 40 and 80 g a.i. ha−1) on weed visual injuries and biomass reduction after herbicide application at different growth stages. As expected, the maximum weed biomass reduction (97.3%) was achieved by applying the highest dose (80 g a.i. ha−1) at the earliest growth stage (ZCK 12–14). A pinoxaden dose of 20 g a.i. ha−1 resulted in satisfactory weed biomass reduction (88.9%) only when applied at ZCK 12–14. The recommended dose (40 g a.i. ha−1) also provided sufficient weed control up to the growth stage ZCK 21–25. Slightly delayed (ZCK 31–32) application of the recommended dose brought about a low weed biomass reduction (60.1%). Double than the recommended dose also failed to provide satisfactory weed control at the advanced weed growth stages (ZCK 31–32 and ZCK 37–39). Thus, reported low efficacy of pinoxaden is most likely because of delayed herbicide application when A. myosuroides is overgrown.


2009 ◽  
Vol 23 (1) ◽  
pp. 49-53 ◽  
Author(s):  
Mark J. VanGessel ◽  
Barbara A. Scott ◽  
Quintin R. Johnson ◽  
Susan E. White-Hansen

Infestations of glyphosate-resistant (GR) horseweed have become widespread in the eastern United States. This biotype is problematic in no-tillage production that relies extensively on glyphosate for weed control. Because horseweed is treated at various stages of growth, a greenhouse study explored rate response of glyphosate-resistant and -susceptible horseweed at three growth stages. GR horseweed was more responsive to glyphosate at the seedling stage than at the large rosette or bolting stages. A field study evaluated GR horseweed response when treated with glyphosate at soybean planting time, POST in-crop (about 45 d after planting), or both at planting and POST in-crop. There was a cumulative effect of the at-planting followed by POST in-crop glyphosate applications. When evaluating single glyphosate applications, the at-planting application was more effective at suppressing GR horseweed than a POST in-crop application. Because glyphosate cannot control GR horseweed, this biotype should be controlled with an herbicide with an alternate mode of action and applied at the most effective timing.


2013 ◽  
Vol 85 (2) ◽  
pp. 813-822 ◽  
Author(s):  
LEONARDO B. DE CARVALHO ◽  
PEDRO L.C.A. ALVES ◽  
STEPHEN O. DUKE

Weed management systems in almost all Brazilian coffee plantations allow herbicide spray to drift on crop plants. In order to evaluate if there is any effect of the most commonly used herbicide in coffee production, glyphosate, on coffee plants, a range of glyphosate doses were applied directly on coffee plants at two distinct plant growth stages. Although growth of both young and old plants was reduced at higher glyphosate doses, low doses caused no effects on growth characteristics of young plants and stimulated growth of older plants. Therefore, hormesis with glyphosate is dependent on coffee plant growth stage at the time of herbicide application.


2017 ◽  
Vol 35 (0) ◽  
Author(s):  
L.F. CIESLIK ◽  
R.A. VIDAL ◽  
A.B. MACHADO ◽  
M.M. TREZZI

ABSTRACT Grass weeds are common in summer crops and strongly decreases the grain yield of the common bean crop. The time of herbicide application influences the variability of environmental conditions and affects the product performance. The objectives of this work were to identify the time of fluazifop-p-butyl (fluazifop) application which gives best grass weed control in the common bean crop and to elucidate the environmental variables most important for the efficacy of this herbicide. Field experiments were conducted involving five application times (2 a.m., 6 a.m., 11 a.m., 4 p.m. and 9 p.m.) and five doses of fluazifop (80, 110, 140, 170 and 200 g ha-1), with additional no-herbicide control. At the time of the herbicide application it was determined the air temperature, relative humidity, the photosynthetically active radiation (PAR) and the leaf angle, whereas the weed control and the dry mass of the weed Urochloa plantaginea was assessed at 20 days after treatment (DAT). Efficacy on grass control with fluazifop was dependent on the herbicide dose and on the time of day that the product was applied. Spray at early morning hours (6 a.m.) showed better efficacy on weed control in relation to periods during warmer conditions of the day (11 a.m. and 4 p.m.). Nocturnal fluazifop application had better weed control when compared to herbicide sprayed in the afternoon. The air temperature, relative humidity and PAR were correlated to weed leaf angle, which correlated the most with fluazifop performance.


2013 ◽  
Vol 31 (4) ◽  
pp. 893-902 ◽  
Author(s):  
C.E. Schaedler ◽  
J.A. Noldin ◽  
D.S. Eberhardt ◽  
D. Agostinetto ◽  
N.R. Burgos

ALS-inhibiting herbicides usually provide adequate weed control in irrigated rice fields. After consecutive years of use, the Cyperaceae species, globe fringerush (Fimbristylis miliacea) began to show resistance to ALS (acetolactate synthase) inhibitors. Globe fringerush is one of the most problematic herbicide-resistant weeds in irrigated rice in the state of Santa Catarina in the South of Brazil. The objective of this research was to examine cross resistance of globe fringerush to ALS inhibitors, under field conditions. Two experiments were conducted in a rice field naturally infested with ALS-resistant globe fringerush in Santa Catarina, in the 2008/09 and 2009/10 cropping seasons. The experimental units were arranged in randomized complete block design, with five replicates, consisting of two factors (herbicide and dose) in a 4 x 5 factorial arrangement. ALS herbicides included bispyribac-sodium, ethoxysulfuron, pyrazosulfuron-ethyl and penoxsulam. Six-leaf globe fringerush was sprayed with herbicide doses of 0, 0.5, 1, 2 and 4X the recommended doses in a spray volume of 200 L ha-1. The number of rice culm, filled and sterile grains, plant height, dry shoot biomass and grain yield were recorded. Globe fringerush control was evaluated 28 and 70 days after herbicide application (DAA); shoots were harvested at 13 weeks after herbicide application and dry weight recorded. Competition with globe fringerush reduced the number of culm and rice grain yield. The globe fringerush biotype in this field was resistant to all ALS herbicides tested. Penoxsulam had the highest level of activity among treatments at 28 and 70 DAA, but the control level was only 50% and 42%, respectively, in the second year of assessment. This was not enough to prevent rice yield loss. Alternative herbicides and weed control strategies are necessary to avoid yield losses in rice fields infested with ALS-resistant biotypes of globe fringerush.


1997 ◽  
Vol 11 (3) ◽  
pp. 515-519 ◽  
Author(s):  
Julio A. Scursoni ◽  
Emilio H. Satorre

The objective of this paper was to evaluate the effect of preplant applications of trifluralin on barley stand and yield, and control of grass weeds in field experiments during 1992 and 1993. Factors examined were: (1) crop planting patterns (conventional drill with rows 15 cm apart and deep-seeder drill with rows 25 cm apart), (2) herbicide application times (22 d before sowing and immediately before sowing), and (3) herbicide application. During 1993, hand-weeded plots also were established. Trifluralin applied preplant at 528 g ai/ha reduced weed density and biomass. Weed control was higher under conventional planting than under the deep planting pattern, and there was no effect of the time of application on herbicide efficacy. There was no herbicide injury to the crop, and grain yield was higher in treated than in untreated plots due to successful weed control.


Author(s):  
M. Youssef ◽  
P.C. Chiy ◽  
C.J.C. Phillips ◽  
M. Metwally

Cattle exhibit preferences not only for certain sward species but for the same species at different stages of growth, and the various parts of an individual plant and for individual plant of preferred composition. This tendency is termed selective grazing (Fontenot and Blaser, 1965). For example ruminants will select a high Sodium diet. Calves tend to be more selective than adult cattle, muzzling herbage before eating.The aim of the present experiment was to investigate the effect of sward complexity, species and sodium fertilizer on the grazing behaviour of calves.Sixteen dairy Friesian calves, aged 5 to 6 months, with no previous grazing experience, were allocated to groups of 4 similar calves, and then at random to four pasture treatments of 3480m2 each with one (Perennial Ryegrass, P), two (P and Timothy, T), three (P, T and Cocksfoot, C) and four (P, T.C and Red Fescue, R) grass species in a balanced change over design. Each species was sown in plots of 290m2 and one half of each plot received 48Kg/ha. nacl.


2010 ◽  
Vol 26 (1) ◽  
pp. 31-37 ◽  
Author(s):  
Frank Forcella ◽  
Trevor James ◽  
Anis Rahman

AbstractCorn gluten meal (CGM) is an approved organic fertilizer and pre-emergence herbicide that can be manufactured in the form of grit. This grit was tested for its ability to abrade seedlings of the summer annual weedy grass, Setaria pumila, when plants were in the 1- to 5-leaf stages of growth. CGM was propelled at air pressures of 250–750 kPa at distances of 30–60 cm from the plants. Established seedlings of S. pumila were controlled more effectively when grit was applied at 500 and 750 kPa than at 250 kPa, as well as when the applicator's nozzle was 30 cm from the plants compared to 60 cm distance. Seedling growth and dry weights were greatly reduced by exposures to grit at 60 cm and 500 kPa for 2 s or less, and seedlings were nearly completely destroyed at 30 cm distance and 750 kPa. CGM, a soft grit, was as effective for abrading seedlings as fine quartz sand, a hard grit. CGM had little pre-emergence herbicidal effect on S. pumila. Although regrowth can occur in S. pumila after abrasion by grit, the initial grit-induced stunting is sufficient to allow competing crop plants, like maize, to escape competition and suppress the weed. Consequently, CGM may be an effective form of soft grit for post-emergence abrasion of seedlings of summer annual grass weeds in organic row crops, while simultaneously supplying the crop with fertilizer.


2015 ◽  
Vol 33 (3) ◽  
pp. 607-614
Author(s):  
G. A. M. PEREIRA ◽  
L. H. BARCELLOS JR ◽  
D. V. SILVA ◽  
R. R. BRAGA ◽  
M. M. TEIXEIRA ◽  
...  

ABSTRACTInadequate herbicide application can result in failures in weed control and/or poisoning of the crops, resulting in yield losses. In this research were assessed the effects of the sprayer nozzle boom height in the distribution of the spray solution for weed control, influencing intoxication of beans and crop yield. Experiments were conducted in laboratory and field conditions. In laboratory, the performance of flat spray tip TT 11002 was assessed at heights 0.20, 0.30, 0.40 and 0.50 meters with respect to the target surface. In the field the same heights were assessed in applications of herbicides fomesafen, fluazifop-P-butyl and fomesafen + fluazifop-P-butyl. There was an inverse relationship between the height of the spray boom and the coefficients of variation of the patterns. The mixture better efficiency in a tank of fluazifop-P-butyl + fomesafen was obtained with the height of 0.50 m from the target. This treatment resulted in better weed control, lower poisoning of the bean plants and better crop yield rates.


Sign in / Sign up

Export Citation Format

Share Document