Weed diversity and soybean yield with glyphosate management along a north–south transect in the United States

Weed Science ◽  
2006 ◽  
Vol 54 (4) ◽  
pp. 713-719 ◽  
Author(s):  
Julio Scursoni ◽  
Frank Forcella ◽  
Jeffrey Gunsolus ◽  
Michael Owen ◽  
Richard Oliver ◽  
...  

There are many concerns about the effects of repeated use of glyphosate in glyphosate-resistant (GR) crops, including two that are seemingly contradictory. These are (1) weed escapes and (2) loss of weed diversity. Weeds that escape glyphosate treatment represent species that likely will become troublesome and difficult to control in the future, and identifying these future problems may allow more effective management. In contrast, complete weed control directly reduces the weed component of agroecosystem biodiversity and may lower other components indirectly (e.g., weed-dependent granivores). During 2001 and 2002 effects of glyphosate and conventional weed control treatments on weed community composition and GR soybean yields were studied. Field studies were conducted along a north–south transect of sites spanning a distance of 1600 km from Minnesota to Louisiana. Low-intensity use (single application yr−1) of glyphosate allowed more escapes and maintained higher weed diversity than high-intensity use (two applications yr−1) of glyphosate, and it was equivalent to or even higher than diversity in non-GR systems. Although the same weeds escaped from low- and high-intensity glyphosate treatments, frequency of escapes was higher with less intensive use. These results suggest that limited use of glyphosate would not have profound effects on weed diversity. In addition, crop yield did not differ between GR and non-GR treatments at high latitudes, but below 40° N latitude, with a longer cropping season, yields with low-intensity glyphosate use decreased by about 2% per degree latitude because of competition from escaped weeds.

2015 ◽  
Vol 29 (4) ◽  
pp. 793-799 ◽  
Author(s):  
Samuel D. Willingham ◽  
Muthukumar V. Bagavathiannan ◽  
Katherine S. Carson ◽  
Todd J. Cogdill ◽  
Garry N. McCauley ◽  
...  

Alligatorweed is a perennial, invasive weed in southern United States rice production, but knowledge on effective management of this weed is limited, especially in conventional (non-imidazolinone-resistant) rice fields. Field studies were conducted in multiple environments in southeastern Texas to evaluate different herbicide options involving penoxsulam, propanil, triclopyr, halosulfuron, bispyribac-sodium, bensulfuron, and quinclorac for alligatorweed control in conventional drill-seeded rice when applied at early POST (EPOST), late POST (LPOST), or both. Among the herbicide options evaluated, penoxsulam alone (up to 83%), penoxsulam plus triclopyr (up to 87%), or bispyribac-sodium plus triclopyr (92%) provided superior alligatorweed control. Plots treated with penoxsulam plus triclopyr EPOST produced the highest yields (9,550 kg ha−1), which were comparable to plots receiving penoxsulam plus triclopyr LPOST (9,320 kg ha−1), penoxsulam alone EPOST (9,280 kg ha−1), and penoxsulam plus halosulfuron LPOST (9,180 kg ha−1). Considering both weed control and rice grain yields, penoxsulam plus triclopyr applied EPOST was found to be the best option among the treatments tested. The treatments bensulfuron alone, bensulfuron plus propanil, penoxsulam plus propanil, triclopyr plus propanil, and bispyribac-sodium plus propanil provided poor (≤ 65%) alligatorweed control. Results also suggest the likelihood for antagonistic interactions when tank-mix combinations tested in this study included propanil.


1988 ◽  
Vol 111 (2) ◽  
pp. 333-337 ◽  
Author(s):  
O. Fadayomi

SummaryField studies were conducted at Ilorin and Bacita during the 1985–6 cropping season to evaluate the use of hexazinone [3-cyclohexyl-6-(dimethylamino)-l methyl-1, 3, 5-triazine-2, 4(1 H, 3H)-dione] alone, and in combination with diuron [3,(3,4-dichlorophenyl)l-l dimethyl urea] in crops of sugar cane. Hexazinone, alone or in combination with diuron, effectively controlled a broad spectrum of weeds in a loamy sand soil at Ilorin. Most of the herbicide rates used were, however, severely phytotoxic to the crop. On silty clay-loam soils at Bacita, the same herbicide treatments, while giving effective control similar to that obtained at Ilorin, were not phytotoxic to the crop. Weed control effectiveness was influenced by the percentage of organic matter in the soils and by the amount of herbicides used. A broader spectrum of weeds was controlled by the mixture of hexazinone plus diuron than by hexazinone alone. There was no difference between the performance of the tank and formulated mixtures of hexazinone plus diuron.


2017 ◽  
Vol 35 (15_suppl) ◽  
pp. e18524-e18524 ◽  
Author(s):  
Bruno C. Medeiros ◽  
Bhavik J. Pandya ◽  
Anna Hadfield ◽  
Samuel Wilson ◽  
Cynthia Mueller ◽  
...  

e18524 Background: The effective treatment of patients with acute myeloid leukemia (AML) remains a challenge in clinical practice. This analysis describes the patient characteristics and real-world use of AML treatments in the United States for patients on high- and low-intensity treatment. Methods: Data from the Adelphi AML Disease-Specific Programme, a real-world, cross-sectional survey conducted between February–May 2015, were analysed. A total of 61 hematologist/hem-oncologists, across academic, non-academic and office-based practice locations, provided data on 457 AML patients. Patient characteristics were derived from physician-completed patient record forms where each physician was asked to provide treatment details, including the treatment intensity, for each line of therapy. Results: A total of 91% (n = 415) of patients included in this analysis were previously untreated for AML. Patients had a mean age of 60 years and been diagnosed with AML for a median of 5.0 months. At first-line induction therapy, over half (53%; n = 241) of the patients were initiated on a high-intensity treatment, the most common regimen being cytarabine plus anthracycline (61%; n = 147). The remaining 47% (n = 216) of patients received a low-intensity induction therapy such as low dose cytarabine monotherapy (28%, n = 61), azacitidine monotherapy (25%, n = 54), or decitabine monotherapy (21%, n = 45). Over half (55%, n = 62) of patients suited to high intensity treatment went on to receive cytarabine monotherapy during the consolidation phase of their first-line treatment. Conclusions: According to treating physicians, the large majority of patients receive traditional, well-established therapies at first-line induction for AML. Whilst cytarabine combinations dominate the high-intensity treatment setting, the hypomethylating agents, azacitidine and decitabine, are frequently used for those more suited to low-intensity treatment.


2019 ◽  
Vol 34 (2) ◽  
pp. 292-300 ◽  
Author(s):  
Graham W. Charles ◽  
Brian M. Sindel ◽  
Annette L. Cowie ◽  
Oliver G. G. Knox

AbstractField studies were conducted over five seasons from 2004 to 2015 to determine the critical period for weed control (CPWC) in high-yielding, irrigated cotton using a competitive mimic grass weed, Japanese millet. Japanese millet was planted with or after cotton emergence at densities of 10, 20, 50, 100, and 200 plants m−2. Japanese millet was added and removed at approximately 0, 150, 300, 450, 600, 750, and 900 degree days of crop growth (GDD). Data were combined over years. Japanese millet competed strongly with cotton, with season-long interference resulting in an 84% reduction in cotton yield with 200 Japanese millet plants m−2. The data were fit to extended Gompertz and logistic curves including weed density as a covariate, allowing a dynamic CPWC to be estimated for densities of 10 to 200 Japanese millet plants m−2. Using a 1% yield-loss threshold, the CPWC commenced at 65 GDD, corresponding to 0 to 7 d after crop emergence (DAE), and ended at 803 GDD, 76 to 98 DAE with 10 Japanese millet plants m−2, and 975 GDD, 90 to 115 DAE with 200 Japanese millet plants m−2. These results highlight the high level of weed control required throughout the cropping season in high-yielding cotton to ensure crop losses do not exceed the cost of weed control.


1999 ◽  
Vol 13 (4) ◽  
pp. 691-696 ◽  
Author(s):  
Ronald F. Krausz ◽  
George Kapusta ◽  
Joseph L. Matthews ◽  
John L. Baldwin ◽  
Jason Maschoff

Field studies were conducted in 1996 and 1997 at Belleville and Pawnee, IL, to evaluate single and sequential applications of glufosinate on tolerance of glufosinate-resistant corn and annual weed control. Glufosinate caused 0 to 13% corn injury 7 days after treatment (DAT) and 0 to 6% corn injury 28 DAT. Injury was characterized as stunting with glufosinate. Glufosinate at 400 to 1,200 g ai/ha did not reduce final corn height or grain yield. At Pawnee in both years and at Belleville in 1996, a single application of glufosinate at 400 g/ha controlled giant foxtail, velvetleaf, ivyleaf morningglory, and common lambsquarters 85 to 100%. At Belleville in 1997, sequential applications of glufosinate provided greater weed control (87 to 100%) than a single application (0 to 63%) because of weed emergence after application. Weed control with a single application of glufosinate or with nicosulfuron plus bromoxynil was similar at both locations. Height and grain yield of glufosinate-resistant corn were not different from that of glufosinate-susceptible corn (isoline of glufosinate-resistant corn).


1999 ◽  
Vol 13 (3) ◽  
pp. 478-483 ◽  
Author(s):  
Jimmy D. Wait ◽  
William G. Johnson ◽  
Raymond E. Massey

Field studies were conducted at two locations in 1997 and 1998 to evaluate crop injury, weed control, yield, and net economic returns of single and sequential postemergence applications of labeled and reduced rates of glyphosate to no-till, glyphosate-resistant soybean planted in narrow rows. Sequential applications provided at least 91% control of giant foxtail, while single applications provided at least 86% control with labeled rates and 68–93% control with reduced rates. Common waterhemp control was slightly higher with sequential vs. single treatments and with labeled rates vs. reduced rates. Velvetleaf control was greater than 96% with all treatments. Common cocklebur control was 90% or higher with all treatments except a single application of glyphosate at 210 g/ha. Lower control of giant foxtail and common waterhemp with single-application, reduced-rate treatments in two of the four trials resulted in lower yields. Overall, sequential applications, regardless of rate, provided greater weed control, yield, and net income and lower coefficients of variation (C.V.s) of net income than reduced-rate single applications. Single-application treatments showed a trend of decreased weed control, yield, and net income and higher C.V.s of net income with reduced rates of glyphosate.


2004 ◽  
Vol 18 (4) ◽  
pp. 1111-1116 ◽  
Author(s):  
Daniel O. Stephenson ◽  
Jason A. Bond ◽  
Eric R. Walker ◽  
Mohammad T. Bararpour ◽  
Lawrence R. Oliver

Field studies were conducted in Arkansas in 1999, 2000, and 2001 to evaluate mesotrione applied preemergence (PRE) and postemergence (POST) for weed control in corn grown in the Mississippi Delta region of the United States. Mesotrione was applied PRE (140, 210, and 280 g/ha) alone and POST (70, 105, and 140 g/ha), alone or in tank mixtures with atrazine (280 g/ha). Standard treatments for comparison were S-metolachlor/atrazine PRE and S-metolachlor plus atrazine PRE followed by atrazine POST. All PRE treatments controlled velvetleaf, pitted morningglory, entireleaf morningglory, prickly sida, and broadleaf signalgrass 95% 2 wk after emergence (WAE). Mesotrione controlled velvetleaf 89% or more 4 and 6 WAE. Control of morningglory species by mesotrione POST averaged 92% 6 WAE. Prickly sida was controlled at least 90% by all treatments 4 WAE. Mesotrione applied alone PRE and POST controlled broadleaf signalgrass 83 to 91% 4 WAE. All treatments controlled broadleaf signalgrass less than 90% 6 WAE, except treatments that contained S-metolachlor, which gave 94% or greater control. Corn yield ranged from 10.5 to 12.4 Mg/ha and did not differ among treatments. Mesotrione PRE and POST provided excellent control of broadleaf weeds, but S-metolachlor was needed for broadleaf signalgrass control.


2014 ◽  
Vol 28 (2) ◽  
pp. 371-376
Author(s):  
O. Steven Norberg ◽  
Joel Felix

Teff is a warm-season C4 annual grass crop grown for forage and food grain that has recently increased in production in parts of the United States. Hay from teff is well suited for livestock, especially horses. The objective of this study was to evaluate teff and weed response to selected herbicides in field studies conducted at the Malheur Experiment Station, Ontario, OR in 2009 and 2010. Herbicides were applied POST when teff was at the four-leaf stage. Broadleaf weed control at 21 d after treatment was greater than 91% across herbicide treatments. Only the premix of 2.5 g ai ha−1florasulam + 99 g ae ha−1fluroxypyr + 15 g ai ha−1pyroxsulam provided acceptable control of barnyardgrass. Due primarily to barnyardgrass competition, teff treated with a premix of 2.5 g ha−1florasulam + 99 g ha−1fluroxypyr + 15 g ha−1pyroxsulam produced 7,200 kg ha−1of teff hay compared with 4,800 kg ha−1of teff hay for 2,4-D and dicamba and 4,200 kg ha−1teff hay when no herbicides were used. Teff grain production was greater with 2.5 g ha−1florasulam + 99 g ha−1fluroxypyr + 15 g ha−1pyroxsulam compared with any of the other treatments. The use of a premix of florasulam + fluroxypyr + pyroxsulam would improve broadleaf and grass weed control in ‘Tiffany' and ‘Dessie' teff varieties, improve hay and grain yield, and reduce production costs.


2006 ◽  
Vol 7 (1) ◽  
pp. 24
Author(s):  
Gerald M. Ghidiu ◽  
Erin Hitchner ◽  
Melissa Zimmerman ◽  
Elwood Rossell

Field studies were conducted during 2004-2005 at the Rutgers Agricultural Research and Extension Center, Bridgeton, NJ to determine the effect of two different nozzle arrangements on the control of the carrot weevil, Listronotus oregonensis (LeConte), in processing carrots (Daucus carota L.). Two drop nozzles per row directed at the base of the plant resulted in significantly fewer damaged carrots caused by carrot weevil feeding each year as compared with a single nozzle centered as a 15.2-cm band located 30.5 cm over the row. However, carrot weevil damage to carrots was high each year in all treatments even during and after multiple pesticide applications, suggesting that growers need to use other management tactics with their spray program. Crop rotation, weed control, and planting date may be as important as pesticide selection and application for effective management of the carrot weevil. Accepted for publication 7 February 2006. Published 3 April 2006.


2021 ◽  
Vol 27 (9) ◽  
pp. 1622-1628
Author(s):  
Emily Breza ◽  
Fatima Cody Stanford ◽  
Marcella Alsan ◽  
Burak Alsan ◽  
Abhijit Banerjee ◽  
...  

AbstractDuring the Coronavirus Disease 2019 (COVID-19) epidemic, many health professionals used social media to promote preventative health behaviors. We conducted a randomized controlled trial of the effect of a Facebook advertising campaign consisting of short videos recorded by doctors and nurses to encourage users to stay at home for the Thanksgiving and Christmas holidays (NCT04644328 and AEARCTR-0006821). We randomly assigned counties to high intensity (n = 410 (386) at Thanksgiving (Christmas)) or low intensity (n = 410 (381)). The intervention was delivered to a large fraction of Facebook subscribers in 75% and 25% of randomly assigned zip codes in high- and low-intensity counties, respectively. In total, 6,998 (6,716) zip codes were included, and 11,954,109 (23,302,290) users were reached at Thanksgiving (Christmas). The first two primary outcomes were holiday travel and fraction leaving home, both measured using mobile phone location data of Facebook users. Average distance traveled in high-intensity counties decreased by −0.993 percentage points (95% confidence interval (CI): –1.616, −0.371; P = 0.002) for the 3 days before each holiday compared to low-intensity counties. The fraction of people who left home on the holiday was not significantly affected (adjusted difference: 0.030; 95% CI: −0.361, 0.420; P = 0.881). The third primary outcome was COVID-19 infections recorded at the zip code level in the 2-week period starting 5 days after the holiday. Infections declined by 3.5% (adjusted 95% CI: −6.2%, −0.7%; P = 0.013) in intervention compared to control zip codes. Social media messages recorded by health professionals before the winter holidays in the United States led to a significant reduction in holiday travel and subsequent COVID-19 infections.


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