Carrot weed management programs without linuron herbicide

2019 ◽  
Vol 33 (03) ◽  
pp. 490-494
Author(s):  
Jed B. Colquhoun ◽  
Richard A. Rittmeyer ◽  
Daniel J. Heider

AbstractLinuron herbicide has been a mainstay of carrot weed management for years, but uncertainty around regulatory registration review and an increased prevalence of herbicide-resistant weeds have spurred interest in identifying alternatives that can be readily adopted in production. With this context in mind, herbicide programs were evaluated on a coarse-textured, low organic matter soil in 2015 and 2016. Season-long weed control without compromising yield was possible with weed management programs that included prometryn POST instead of linuron. With that said, a PRE herbicide such as pendimethalin was critical to establish an early-season competitive advantage for carrot plants over weeds, and careful attention should be paid to the prometryn rate, as selectivity is marginal. Carrot is often interseeded with a grain nurse crop to mitigate risk of wind erosion. Nurse crop injury was minimal where S-metolachlor, pendimethalin, or prometryn was applied at rates labeled for PRE use in carrot, with the exception of where prometryn was applied at rates above 1.1 kg ai ha−1.

2005 ◽  
Vol 75 (4) ◽  
pp. 79-84 ◽  
Author(s):  
D. Shaner

Some of the first products of biotechnology to reach the marketplace have been herbicide-resistant crops. Industry sees the development of herbicide-resistant varieties as a way to increase the availability of proven herbicides for a broader range of crops. However, the development of herbicide- resistant crops requires special attention to potential environmental questions such as herbicide usage, selection of resistant weed biotypes and spread of resistance from the resistant crop to wild species. Industry is actively addressing these concerns during the process of development. Proper development and use of herbicide-resistant crops in integrated weed management programs will provide farmers with increased flexibility, efficiency, and decreased cost in their weed control practices without increasing the risk of herbicide-resistant weeds. Furthermore, herbicide-resistant crops should prove to be valuable tools in managing herbicide- resistant weeds.


2019 ◽  
Vol 33 (03) ◽  
pp. 411-425
Author(s):  
Andrea Smith ◽  
Nader Soltani ◽  
Allan J. Kaastra ◽  
David C. Hooker ◽  
Darren E. Robinson ◽  
...  

AbstractTransgenic crops are being developed with herbicide resistance traits to expand innovative weed management solutions for crop producers. Soybean with traits that confer resistance to the hydroxyphenylpyruvate dioxygenase herbicide isoxaflutole is under development and will provide a novel herbicide mode of action for weed management in soybean. Ten field experiments were conducted over 2 years (2017 and 2018) on five soil textures with isoxaflutole-resistant soybean to evaluate annual weed control using one- and two-pass herbicide programs. The one-pass weed control programs included isoxaflutole plus metribuzin, applied PRE, at a low rate (52.5 + 210 g ai ha−1), medium rate (79 + 316 g ai ha−1), and high rate (105 + 420 g ai ha−1); and glyphosate applied early postemergence (EPOST) or late postemergence (LPOST). The two-pass weed control programs included isoxaflutole plus metribuzin, applied PRE, followed by glyphosate applied LPOST, and glyphosate applied EPOST followed by LPOST. At 4 weeks after the LPOST application, control of common lambsquarters, pigweed species, common ragweed, and velvetleaf was variable at 25% to 69%, 49% to 86%, and 71% to 95% at the low, medium, and high rates of isoxaflutole plus metribuzin, respectively. Isoxaflutole plus metribuzin at the low, medium, and high rates controlled grass species evaluated (i.e., barnyardgrass, foxtail, crabgrass, and witchgrass) 85% to 97%, 75% to 99%, and 86% to 100%, respectively. All two-pass weed management programs provided 98% to 100% control of all species. Weed control improved as the rate of isoxaflutole plus metribuzin increased. Two-pass programs provided excellent, full-season annual grass and broadleaf weed control in isoxaflutole-resistant soybean.


2004 ◽  
Vol 18 (4) ◽  
pp. 1006-1012 ◽  
Author(s):  
K. Neil Harker ◽  
George W. Clayton ◽  
John T. O'Donovan ◽  
Robert E. Blackshaw ◽  
F. Craig Stevenson

Herbicide-resistant canola dominates the canola market in Canada. A multiyear field experiment was conducted at three locations to investigate the effect of time of weed removal (two-, four-, or six-leaf canola) and herbicide rate (50 or 100% recommended) in three herbicide-resistant canola systems. Weeds were controlled in glufosinate-resistant canola (GLU) with glufosinate, in glyphosate-resistant canola (GLY) with glyphosate, and in imidazolinone-resistant canola (IMI) with a 50:50 mixture of imazamox and imazethapyr. Canola yields were similar among the three canola cultivar–herbicide systems. Yields were not influenced by 50 vs. 100% herbicide rates. Timing of weed removal had the greatest effect on canola yield, with weed removal at the four-leaf stage giving the highest yields in most cases. Percent dockage was often greater for GLU and IMI than for GLY. In comparison with the other treatments, dockage levels doubled for GLU after application at 50% herbicide rates. The consistency of monocot weed control was usually greater for GLY than for GLU or IMI systems. However, weed biomass data revealed no differences in dicot weed control consistency between IMI and GLY systems. Greater dockage and weed biomass variability after weed removal at the six-leaf stage or after low herbicide rates suggests higher weed seed production, which could constrain the adoption of integrated weed management practices in subsequent years.


Weed Science ◽  
1995 ◽  
Vol 43 (1) ◽  
pp. 121-127 ◽  
Author(s):  
Jon E. Scott ◽  
Leslie A. Weston ◽  
R. Terry Jones

Experiments were conducted at Lexington and Quicksand, KY, in 1989 and 1990 to determine the effect of preplant incorporated clomazone on weed control, crop injury, and yield of broccoli, cauliflower, green cabbage, red cabbage, and pak choi. Oxyfluorfen and trifluralin were included as standard treatments. Greater than 80% weed control was observed at both locations with 0.8 kg ai ha−1clomazone, with the exception of smooth pigweed at Lexington. All clomazone treatments caused crop injury 2 WAT. Injury was still evident 8 WAT at clomazone rates of 1.7 and 3.4 kg ha−1, but was minor with rates of 0.8 kg ha−1or less on broccoli, cauliflower, and red cabbage. Injury was less at Quicksand in both years and seasons over all clomazone rates, most likely due to higher soil organic matter content Yields of broccoli and cauliflower treated with 0.8 kg ha−1clomazone were similar to yields with oxyfluorfen on a 3% organic matter soil at Lexington in 1989. However, clomazone at 0.8 kg ha−1at Lexington reduced 1989 spring yields of green cabbage, red cabbage, and pak choi and 1990 spring yields of all cole crops as compared to oxyfluorfen. Clomazone at 0.8 kg ha−1at Quicksand reduced yield of green cabbage and pak choi in spring 1990 only on a 5.2% organic matter soil. Fall yields of broccoli and cauliflower in both years were not reduced by clomazone at 0.8 kg ha−1or less at either location. Our studies indicated potential for utilization of clomazone on cole crops in higher organic matter soils, especially if some early season crop injury and occasional yield loss can be tolerated.


Weed Science ◽  
2011 ◽  
Vol 59 (3) ◽  
pp. 390-397 ◽  
Author(s):  
Ivan Sartorato ◽  
Antonio Berti ◽  
Giuseppe Zanin ◽  
Claudio M. Dunan

The introduction of herbicide-resistant crops and postemergence herbicides with a wide action spectrum shifted the research focus from how to when crops should be treated. To maximize net return of herbicide applications, the evolution of weed–crop competition over time must be considered and its effects quantified. A model for predicting the yield trend in relation to weed removal time, considering emergence dynamics and density, was tested on data from glyphosate-resistant soybean grown in cropping systems in Italy and Argentina. Despite an ample variation of weed emergence dynamics and weed load in the four trials, the model satisfactorily predicted yield loss evolution. The estimated optimum time for weed control (OTWC) varied from about 18 d after soybean emergence in Argentina to 20 to 23 d in Italy, with time windows for spraying ranging from 14 to 28 d. Within these limits a single glyphosate application ensures good weed control at low cost and avoids side effects like the more probable unfavorable weed flora evolution with double applications and the presence of residues in grains. Despite the apparent simplicity of weed control based on nonselective herbicides, the study outlines that many variables have to be considered to optimize weed management, particularly for the time evolution of the infestation and, subsequently, a proper timing of herbicide application.


2016 ◽  
Vol 30 (2) ◽  
pp. 366-376 ◽  
Author(s):  
M. Ryan Miller ◽  
Jason K. Norsworthy

Two separate field experiments were conducted over a 2-yr period in Fayetteville, AR, during 2012 and 2013 to (1) evaluate POST herbicide programs utilizing a premixture of dimethylamine (DMA) salt of glyphosate + choline salt of 2,4-D in a soybean line resistant to 2,4-D, glyphosate, and glufosinate and (2) determine efficacy of herbicide programs that begin with PRE residual herbicides followed by POST applications of 2,4-D choline + glyphosate DMA on glyphosate-resistant Palmer amaranth. In the first experiment, POST applications alone that incorporated the use of residual herbicides with the glyphosate + 2,4-D premixture provided 93 to 99% control of Palmer amaranth at the end of the season. In the second experiment, the use of flumioxazin, flumioxazin + chlorimuron methyl, S-metolachlor + fomesafen, or sulfentrazone + chloransulam applied PRE provided 94 to 98% early-season Palmer amaranth control. Early-season control helped maintain a high level of Palmer amaranth control throughout the growing season, in turn resulting in fewer reproductive Palmer amaranth plants present at soybean harvest compared to most other treatments. Although no differences in soybean yield were observed among treated plots, it was evident that herbicide programs should begin with PRE residual herbicides followed by POST applications of glyphosate + 2,4-D mixed with residual herbicides to minimize late-season escapes and reduce the likelihood of contributions to the soil seedbank. Dependent upon management decisions, the best stewardship of this technology will likely rely on the use multiple effective mechanisms of action incorporated into a fully integrated weed management system.


2011 ◽  
Vol 25 (1) ◽  
pp. 6-13 ◽  
Author(s):  
Jason K. Norsworthy ◽  
Marilyn McClelland ◽  
Griff Griffith ◽  
Sanjeev K. Bangarwa ◽  
Joshua Still

Research was conducted for 2 yr at Marianna, AR, to determine whether the fall-planted cover crops rye, wheat, turnip, and a blend of brown and white mustard (Caliente) would aid weed management programs in conservation-tilled, enhanced, glyphosate-resistant cotton. Wheat and rye easily were established both years and turnip and mustard blend stands were better in the second year. The cover crops alone were more suppressive of Palmer amaranth, pitted morningglory, and goosegrass in 2007 than in 2008. Rye was generally superior to wheat in suppressing the three evaluated weeds. Once herbicides were applied, there were seldom differences among cover crops for a particular herbicide program as a result of the highly efficacious herbicide programs. Cotton yields were not affected by wheat, rye, or the mustard blend, but yields were lowest in plots that followed turnip both years, possibly because of allelopathy. Integration of cover crops, especially cereals, into conservation-tilled, glyphosate-resistant cotton aided early-season weed management and could reduce the selection of glyphosate for herbicide resistance.


HortScience ◽  
1999 ◽  
Vol 34 (3) ◽  
pp. 554C-554
Author(s):  
Yahya K. Al-Hinai ◽  
Teryl R. Roper

This experiment was conducted to determine temporal and spatial weed management characteristics for tart cherry orchards. Annual ryegrass and lambsquarter were planted in tree rows of a 14-year-old tart cherry orchard. Vegetation was controlled with nonresidual herbicides (Gramoxone + B-1956) either all season, May, June, July, August, before harvest, after harvest, or not controlled. Shoot growth measurements showed significantly more growth by trees without weed competition during the entire season, May, June, and before harvest compared to the weedy control and postharvest, July, or August treatments. Weedy early season plots reduced the shoot growth by half. All season, before harvest, May, and June weed-free plots showed higher amounts of leaf N compared with weedy controls or late-season treatments. Early season weed control is more important than late season. Vegetation-free areas of 0, 2, 3, and 4 m2 were maintained during 1998 by postemergence herbicides. Tissue analysis showed higher N concentration in leaves with vegetation controlled to 2 m2 or more compared to the weedy control. The critical vegetation free area for young cherry trees is between 0 and 2 m2.


2020 ◽  
Vol 100 (6) ◽  
pp. 692-696
Author(s):  
Nader Soltani ◽  
Lynette R. Brown ◽  
Peter H. Sikkema

Herbicide-resistant (HR) crops, specifically glyphosate-, glufosinate-, and dicamba-resistant (HT3) soybean, will offer producers a new weed management option for the control of some HR weeds in soybean. Four field experiments were conducted near Cottam and on Walpole Island, ON, Canada, during 2017 and 2018 to assess the control of multiple-resistant (MR) waterhemp (herbicide groups 2, 5, and 9) in HT3 soybean treated with various herbicide programs. Pyroxasulfone/flumioxazin, flumioxazin plus metribuzin, or S-metolachlor/metribuzin applied preemergence (PRE) and followed by (fb) glyphosate postemergence (POST) controlled MR waterhemp at 94%, 66%, and 78%, respectively, in early September. Pyroxasulfone/flumioxazin, flumioxazin plus metribuzin, or S-metolachlor/metribuzin applied PRE controlled MR waterhemp 86%–97% when fb glufosinate POST; 100% when fb glyphosate plus dicamba POST; 99%–100% when fb glufosinate plus dicamba POST; and 100% when fb glyphosate plus dicamba POST and fb glufosinate POST2 (before the R2 soybean growth stage) in early September. Reduced MR waterhemp interference with all herbicide programs resulted in an increase in HT3 soybean yield (up to 59%) relative to the weedy control. Results indicate that pyroxasulfone/flumioxazin, flumioxazin plus metribuzin, or S-metolachlor/metribuzin applied PRE fb glufosinate POST, glyphosate plus dicamba POST, glufosinate plus dicamba POST, or glyphosate plus dicamba POST fb glufosinate POST2 provides similar and excellent season-long control of MR waterhemp in HT3 soybean.


1996 ◽  
Vol 10 (2) ◽  
pp. 327-336 ◽  
Author(s):  
J. Rolf Olsen ◽  
Jayson K. Harper ◽  
William S. Curran

A computer model which selects least cost herbicide programs given a minimum desired level of weed control could provide growers with economical weed management options. Using an integer programming approach, a herbicide selection model was developed for corn production under Pennsylvania conditions. Models for three rotations (corn-soybean, corn-corn, and corn-alfalfa) under three tillage systems (conventional tillage, reduced tillage, and no-till) that evaluated 21 soil-applied and 13 postemergence herbicide options for 24 weeds were developed. Each model minimizes the cost of a herbicide program subject to a desired level of weed control. By selecting the weed species to be controlled and the level of control desired, customized herbicide programs can be generated. The models can also be used to evaluate the cost of changing the level of control desired for an individual weed species or set of weeds.


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