scholarly journals Single and sequential applications of dicamba for the control of glyphosate-resistant common ragweed in glyphosate- and dicamba-resistant soybean

2018 ◽  
Vol 98 (3) ◽  
pp. 552-556
Author(s):  
Holly P. Byker ◽  
Annemarie C. Van Wely ◽  
Nadar Soltani ◽  
Mark B. Lawton ◽  
Darren E. Robinson ◽  
...  

Confirmation of glyphosate-resistant (GR) weeds in southwestern Ontario has led to a change in weed management practices, particularly in soybean. Registered soil-applied herbicides have been identified that have activity on GR common ragweed; however, due to the long emergence period of common ragweed, additional postemergence options are required. The recent development of glyphosate- and dicamba-resistant soybean (Roundup Ready Xtend soybean) allows for the preplant and postemergence application of dicamba. Three field studies were conducted in Ontario, Canada, in a field with confirmed GR common ragweed. Glyphosate-resistant common ragweed interference resulted in 75% yield loss in soybean compared with the weed-free check. At 4 wk after application, dicamba tank-mixed with glyphosate applied preplant only, postemergence only, or preplant followed by postemergence controlled GR common ragweed up to 94%, 87%, and 99%, respectively. The availability of dicamba for use in glyphosate- and dicamba-resistant soybean will provide an additional mode of action for weed management in soybean.

1998 ◽  
Vol 12 (3) ◽  
pp. 522-526 ◽  
Author(s):  
Theodore M. Webster ◽  
John Cardina ◽  
Mark M. Loux

The objectives of this study were to determine how the timing of weed management treatments in winter wheat stubble affects weed control the following season and to determine if spring herbicide rates in corn can be reduced with appropriately timed stubble management practices. Field studies were conducted at two sites in Ohio between 1993 and 1995. Wheat stubble treatments consisted of glyphosate (0.84 kg ae/ha) plus 2,4-D (0.48 kg ae/ha) applied in July, August, or September, or at all three timings, and a nontreated control. In the following season, spring herbicide treatments consisted of a full rate of atrazine (1.7 kg ai/ha) plus alachlor (2.8 kg ai/ha) preemergence, a half rate of these herbicides, or no spring herbicide treatment. Across all locations, a postharvest treatment of glyphosate plus 2,4-D followed by alachlor plus atrazine at half or full rates in the spring controlled all broadleaf weeds, except giant ragweed, at least 88%. Giant foxtail control at three locations was at least 83% when a postharvest glyphosate plus 2,4-D treatment was followed by spring applications of alachlor plus atrazine at half or full rates. Weed control in treatments without alachlor plus atrazine was variable, although broadleaf control from July and August glyphosate plus 2,4-D applications was greater than from September applications. Where alachlor and atrazine were not applied, August was generally the best timing of herbicide applications to wheat stubble for reducing weed populations the following season.


Weed Science ◽  
2006 ◽  
Vol 54 (02) ◽  
pp. 380-390 ◽  
Author(s):  
Sharon A. Clay ◽  
Bruce Kreutner ◽  
David E. Clay ◽  
Cheryl Reese ◽  
Jonathan Kleinjan ◽  
...  

Weeds generally occur in patches in production fields. Are these patches spatially and temporally stable? Do management recommendations change on the basis of these data? The population density and location of annual grass weeds and common ragweed were examined in a 65-ha corn/soybean production field from 1995 to 2004. Yearly treatment recommendations were developed from field means, medians, and kriging grid cell densities, using the hyperbolic yield loss (YL) equation and published incremental YL values (I), maximum YL values (A), and YL limits of 5, 10, or 15%. Mean plant densities ranged from 12 to 131 annual grasses m−2and < 1 to 37 common ragweed m−2. Median weed densities ranged from 0 to 40 annual grasses m−2and were 0 for common ragweed. The grassIvalues used to estimate corn YL were 0.1 and 2% and treatment was recommended in only 1 yr when the highIvalue and either the mean or median density was used. The grassIvalues used for soybean were 0.7 and 10% and estimated YL was over 10% all years, regardless ofIvalue. The common ragweedIvalues were 4.5 and 6% for corn and 5.1 and 15.6% for soybean. On the basis of mean densities, fieldwide treatment would have been recommended in 6 of 9 yr but in no years when the median density was used. Recommendations on the basis of grid cell weed density and kriging ranged from > 80% of the field treated for grass weeds in 3 of 4 yr in soybean to < 20% of the field treated for common ragweed in 2002 and 2004 (corn). Grass patches were more stable in time, space, and density than common ragweed patches. Population densities and spatial distribution generally were variable enough so that site-specific information within this field would improve weed management decisions.


2006 ◽  
Vol 46 (9) ◽  
pp. 1177 ◽  
Author(s):  
J. A. Werth ◽  
C. Preston ◽  
G. N. Roberts ◽  
I. N. Taylor

Forty growers in 4 major cotton-growing regions in Australia were surveyed in 2003 to investigate how the adoption of glyphosate-tolerant cotton (Roundup Ready) had influenced herbicide use, weed management techniques, and whether changes to the weed spectrum could be identified. The 10 most common weeds reported on cotton fields were the same in glyphosate-tolerant and conventional fields in this survey. Herbicide use patterns were altered by the adoption of glyphosate-tolerant cotton with up to 6 times more glyphosate usage, but 21% fewer growers applying pre-emergence herbicides in glyphosate-tolerant fields. Other weed control practices such as the use of post-emergence herbicides, inter-row cultivation and hand hoeing were only reduced marginally. However, growers indicated that management practices are likely to change over time, especially with the introduction of enhanced glyphosate tolerance technology (Roundup Ready Flex), and anticipate a 32% decrease in the number of growers using alternative weed management practices. To date, management practices other than glyphosate use have not changed markedly in glyphosate-tolerant cotton indicating a conservative approach by growers adopting this technology and reflecting the narrow window of herbicide application. The range of weed control options still being employed in glyphosate-tolerant cotton would not increase the risk of glyphosate resistance development.


Weed Science ◽  
2006 ◽  
Vol 54 (1) ◽  
pp. 94-99 ◽  
Author(s):  
Martin M. Williams ◽  
Rick A. Boydston

Weed management systems in carrot are limited in part by a lack of fundamental understanding of crop–weed interactions. Irrigated field studies were conducted to quantify the effect of volunteer potato density and duration of interference on carrot yield and to determine relationships among weed density, duration of weed growth, and volunteer potato tuber production. A season-long volunteer potato density of 0.06 plants m−2produced from 150 to 230 g tubers m−2and resulted in an estimated 5% crop yield loss. At two volunteer potato plants m−2, the same level of crop loss was estimated with a duration of interference of 430 growing degree days (GDD), a time at which the weed had already produced 130 g tubers m−2. Volunteer potato height at the time of weed removal predicted carrot yield loss (R2= 0.77) and may be useful for timing of management strategies such as hand weeding. Functional relationships describing carrot–volunteer potato interactions provide simple information that is useful for developing weed management recommendations for carrot, a crop that relies on multiple tactics for managing weeds, and rotational crops that are negatively affected by persistence of volunteer potato.


2014 ◽  
Vol 28 (4) ◽  
pp. 653-659 ◽  
Author(s):  
M. Ryan Miller ◽  
Peter J. Dittmar ◽  
Gary E. Vallad ◽  
Jason A. Ferrell

Integrated management programs are becoming increasingly necessary for nutsedge control in the absence of methyl bromide. In 2012, field studies were established and maintained for a period of 2 yr at two locations to evaluate the additive effect of fallow programs and preplant fumigants for nutsedge control in bell pepper. The study included eight fallow programs consisting of eight combinations of glyphosate (G) and cultivation (C), and two fumigants; 1,3-dichloropropene + chloropicrin, dimethyl-disulfide + chloropicrin, and a nontreated check. All fallow programs provided greater late-season control of nutsedge compared to the nontreated, with the greatest control of nutsedge observed with glyphosate fb (followed by) glyphosate (GG) and glyphosate fb cultivation fb glyphosate (GCG) fallow programs. Fumigation provided additional nutsedge control in single-input fallow programs. Increased marketable yield was observed in 2012 with the application of either fumigant compared to a nonfumigated control. Furthermore, increased marketable yield was observed with more intensive fallow programs in 2013. Nutsedge control in bell pepper was significantly increased when a fallow program was used in combination with other weed-management practices.


Weed Science ◽  
2008 ◽  
Vol 56 (3) ◽  
pp. 477-483 ◽  
Author(s):  
Jim S. Broatch ◽  
Lloyd M. Dosdall ◽  
John T. O'Donovan ◽  
K Neil Harker ◽  
George W. Clayton

Weed management strategies can influence insect infestations in field crops, yet no attempts have been made previously to manipulate weed populations in canola for integrated weed and insect management. Field studies were conducted during 2003 to 2005 at Lacombe and Beaverlodge, Alberta, Canada to manipulate weed and root maggot, Delia spp. (Diptera: Anthomyiidae), interactions in canola. Densities of monocot weeds were varied by altering herbicide applications, with rates ranging from 0 to 100% of the rate recommended. Weed populations declined, and yields were variable with increased herbicide rates. Root maggot damage decreased with increases in monocot weed dry weight for both canola species at both study sites. Results support the hypothesis that heterogenous environments, arising from mixed populations of monocot weeds with canola, minimize opportunities for females of Delia spp. to complete the behavioral sequence required for oviposition, leading to reduced infestation levels in weedy systems. However, effects of dicot weeds on root maggot infestations varied between sites as a result of site-related differences in weed species complexes. When wild mustard was common, crop damage increased, because this weed can serve as an alternate host for root maggots. The study emphasizes the importance of adopting crop management practices that are compatible for both weed and root maggot control.


1999 ◽  
Vol 13 (1) ◽  
pp. 104-111 ◽  
Author(s):  
Lee R. Van Wychen ◽  
R. Gordon Harvey ◽  
Mark J. Vangessel ◽  
Thomas L. Rabaey ◽  
David J. Bach

Field studies were conducted at Arlington, WI, in 1996 and 1997 and at Georgetown, DE, and LeSueur, MN, in 1997 to determine weed control efficacy, crop injury, and yield response of PAT-transformed sweet corn to glufosinate-based weed management. Sequential applications of glufosinate 10 to 18 d apart at 0.4 and 0.3 kg ai/ha controlled common lambsquarters, common ragweed, velvetleaf, wild-proso millet, and fall panicum 90% or better at all locations. Weed control varied little among 0.3, 0.4, or 0.3 and 0.3 (sequential) kg/ha glufosinate rates. Glufosinate applied alone, with, or following atrazine controlled velvetleaf 90% or greater but was less consistent on common ragweed and common lambsquarters (73 to 100%). Atrazine plus metolachlor applied preemergence (PRE) and glufosinate applied alone postemergence (POST) provided inconsistent wild-proso millet and fall panicum control (43 to 99%). Metolachlor followed by glufosinate improved consistency of grass control (> 76%). Glufosinate followed by cultivation provided 80% or greater control of velvetleaf and wild-proso millet. Glufosinate did not injure or delay maturity of PAT-transformed sweet corn. Sweet corn treated with glufosinate resulted in yields greater than or equal to the sweet corn that was hand-weeded or received a standard herbicide treatment.


2019 ◽  
Vol 46 (2) ◽  
pp. 182-190
Author(s):  
A.T. Hare ◽  
D.L. Jordan ◽  
R.G. Leon ◽  
K.L. Edmisten ◽  
A.R. Post ◽  
...  

ABSTRACT Field studies were conducted in 2016 and 2017 at two locations in North Carolina to evaluate common ragweed (Ambrosia artemiisifolia L.) (Lewiston-Woodville) and Palmer amaranth (Amanthus palmeri S. Wats) control (Rocky Mount), peanut (Arachis hypogaea L.) yield, and estimated economic return when herbicides were applied postemergence (POST) at 2 or 6 weeks after planting (WAP); 2 and 4 WAP; 4 and 6 WAP; and 2, 4, and 6 WAP. During the following growing season, cotton (Gossypium hirsutum L.) was planted directly into the same plots to determine the impact of weed management during the previous season on weed density. In absence of herbicides, peanut yield was 880 and 1110 kg/ha at Lewiston-Woodville and Rocky Mount, respectively. When weed control depended on a single herbicide application, yield ranged from 1760 to 2660 kg/ha at Lewiston-Woodville, and 2080 to 2480 kg/ha at Rocky Mount. When herbicides were applied twice, peanut yield ranged from 2690 to 3280 kg/ha at Lewiston-Woodville and 3420 to 3840 kg/ha at Rocky Mount. The greatest yields were recorded when herbicides were applied two or three times. Applying herbicides increased the estimated economic return of peanut compared to the non-treated control (NTC). In cotton the following year, common ragweed populations at Lewiston-Woodville were greater following the NTC or a single herbicide application 2 WAP compared to more intensive herbicide programs. Palmer amaranth density at Rocky Mount the following year in cotton was not affected by weed management the previous year in peanut. These results illustrate the relative importance of timing and duration of weed management for peanut and how they influence weed emergence in the following cotton rotational crop.


EDIS ◽  
2020 ◽  
Vol 2020 (3) ◽  
Author(s):  
Jason A. Ferrell ◽  
Gregory E. MacDonald ◽  
Pratap Devkota

Successful weed control is essential for economical corn production in Florida. Weeds reduce corn yields by competing for moisture, nutrients, and light during the growing season and interfere with harvest. Producing a good corn crop is only half the battle and will not be profitable unless the corn can be harvested. Late-season weeds can result in excessive yield loss, inefficient equipment operation, and provide a source of weed seed for the following season. Weeds can be controlled in corn; however, this involves good management practices in all phases of corn production.https://edis.ifas.ufl.edu/wg007


2006 ◽  
Vol 20 (3) ◽  
pp. 651-657 ◽  
Author(s):  
Wesley J. Everman ◽  
Scott B. Clewis ◽  
Zachary G. Taylor ◽  
John W. Wilcut

Field studies were conducted at Lewiston–Woodville and Rocky Mount, NC in 2001 and 2002 to evaluate weed control and peanut response to POST treatments of diclosulam at various rates and application timings. Diclosulam controlled common ragweed and entireleaf morningglory when applied within 35 d after planting (DAP). Common ragweed 61 cm tall was controlled ≥92% with 4 to 13 g ai/ha diclosulam and larger common ragweed (107 to 137 cm tall) were controlled ≥97% with 27 g/ha diclosulam. Common lambsquarters was controlled 62% or less with all diclosulam POST treatments following metolachlor applied PRE, which provided 48% control. Peanut injury was less than 15% with all diclosulam POST treatments and was transitory. In separate studies, POST diclosulam treatments did not affect peanut yield in a weed-free environment. Peanut yield in weedy environments was reduced as the diclosulam application timing was delayed because of early season weed interference. A linear relationship was observed between yield and application timing with yield decreasing as application timing was delayed. This yield response documents the importance of early season weed management for maximizing peanut yield potential. Virginia peanut varieties were not affected by different POST rates of diclosulam; however, early season peanut injury showed a linear and quadratic relationship with diclosulam rate and was less than 14% at rates as high as 71 g/ha, and was not apparent by late season.


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