Efficacy of Interrow Weed Control Techniques in Wide Row Narrow-Leaf Lupin

2011 ◽  
Vol 25 (1) ◽  
pp. 135-140 ◽  
Author(s):  
Abul Hashem ◽  
R. Michael Collins ◽  
David G. Bowran

The sharp decline in the area of lupin grown in Australia is partly attributed to the failure to control herbicide-resistant weeds in narrow-leaf lupin crops grown with the conventional 25-cm-wide row spacing. Growing lupin with wider row spacing allows for interrow weed control by nonselective herbicides using a sprayshield or physical methods. During 2003 to 2006, two experiments conducted at five sites evaluated the efficacy of interrow weed control techniques in narrow-leaf lupin crops grown in 55- to 65-cm-wide rows within the Western Australia wheatbelt. Interrow herbicides were applied POST using sprayshields, intrarow herbicides were banded on lupin rows at seeding, and interrow weeds were mowed using a garden mower. The main weed species at each site was rigid ryegrass, blue lupin, or wild radish. Paraquat plus diquat applied on the interrow of the lupin crop with sprayshields controlled up to 100% of weeds between rows, leading to increases in lupin grain yield in most of the sites. Glyphosate alone, a mixture of glyphosate plus metribuzin, and glyphosate followed by paraquat plus diquat also controlled interrow weeds, but did not increase lupin grain yield at any site. Thus, paraquat plus diquat is a better choice for interrow weed control in wide row lupin than glyphosate. Mowing did not improve weed control, but mowing followed by paraquat plus diquat increased lupin grain yield at one site. Regression models predicted that there was a strong relationship between weed biomass and lupin grain yield.

2017 ◽  
Vol 11 ◽  
Author(s):  
Euro Pannacci ◽  
Francesco Tei ◽  
Marcello Guiducci

Three field experiments were carried out in organic winter wheat in three consecutive years (exp. 1, 2005-06; exp. 2, 2006-07; exp. 3, 2007-08) in central Italy (42°57' N - 12°22' E, 165 m a.s.l.) in order to evaluate the efficacy against weeds and the effects on winter wheat of two main mechanical weed control strategies: 1) spring tine harrowing used at three different application times (1 passage at T1; 2 passages at the time T1; 1 passage at T1 followed by 1 passage at T1 + 14 days) in the crop sowed at narrow (traditional) row spacing (0.15 m) and 2) split-hoeing and finger-weeder, alone and combined at T1, in the crop sowed at wider row spacing (0.30 m). At the time T1 winter wheat was at tillering and weeds were at the cotyledons-2 true leaves growth stage. The experimental design was a split-plot with four replicates. Six weeks after mechanical treatments, weed ground cover (%) was rated visually using the Braun–Blanquet cover-abundance scale; weeds on three squares (0.6 x 0.5 m each one) per plot were collected, counted, weighed, dried in oven at 105 °C to determine weed density and weed above-ground dry biomass. At harvest, wheat ears density, grain yield, weight of 1000 seeds and hectolitre weight were recorded. Total weed flora was quite different in the three experiments. The main weed species were: <em>Polygonum aviculare</em> L. (exp. 1 and 2), <em>Fallopia convolvulus</em> (L.) Á. Löve (exp. 1 and 3), <em>Stachys annua</em> (L.) L. (exp. 1), <em>Anagallis arvensis</em> L. (exp. 2), <em>Papaver rhoeas</em> L. (exp.3), <em>Veronica hederifolia</em> L. (exp. 3). In the winter wheat sowed at narrow rows, 2 passages with spring-tine harrowing at the same time seems to be the best option in order to reconcile a good efficacy with the feasibility of treatment. In wider rows spacing the best weed control was obtained by splithoeing alone or combined with finger-weeder. The grain yield, on average 10% higher in narrow rows, the lower costs and the good selectivity of spring-tine harrowing treatments seems to suggest the adoption of narrow rows spacing in wheat in organic and low-input farming systems.


2010 ◽  
Vol 24 (3) ◽  
pp. 310-318 ◽  
Author(s):  
Blakely H. Paynter

Field studies compared the grain yield of four two-row spring barley cultivars at four sites when sown at two-row spacing in competition with two densities of rigid ryegrass. The sites chosen had low background populations of rigid ryegrass. Although the four cultivars sown differed in their grain yield, row spacing did not influence cultivar performance. Doubling the row spacing decreased barley grain yield at three of the four sites. The impact of row spacing on grain yield was more noticeable when doubled to 48 or 50 cm compared with 36 cm. Rigid ryegrass competition reduced barley grain yield at two of the four sites. At both locations the influence of weed competition on barley grain yield was the same at both narrow and wide row spacing and at one location the impact of weed competition was modified by cultivar. Planting barley in wide rows was found to favor rigid ryegrass production through an increase in both rigid ryegrass biomass production and tiller number. The development of farming systems for barley on the basis of a row spacing greater than 25 cm is likely to be associated with an increase in weed productivity unless good integrated weed management principles are implemented. Modifications to the current system may allow an increase in row spacing without any yield loss or increased weed seed set.


1990 ◽  
Vol 4 (2) ◽  
pp. 245-249 ◽  
Author(s):  
Brenda S. Smith ◽  
Don S. Murray ◽  
J. D. Green ◽  
Wan M. Wanyahaya ◽  
David L. Weeks

Barnyardgrass, large crabgrass, and Texas panicum were evaluated in field experiments over 3 yr to measure their duration of interference and density on grain sorghum yield. When grain yield data were converted to a percentage of the weed-free control, linear regression predicted a 3.6% yield loss for each week of weed interference regardless of year or grass species. Grain sorghum grown in a narrow (61-cm) row spacing was affected little by full-season interference; however, in wide (91-cm) rows, interference increased as grass density increased. Data from the wide-row spacing were described by linear regression following conversion of grain yield to percentages and weed density to log10. A separate nonlinear model also was derived which could predict the effect of weed density on grain sorghum yield.


2021 ◽  
pp. 1-28
Author(s):  
Nicholas T. Basinger ◽  
Nicholas S. Hill

Abstract With the increasing focus on herbicide-resistant weeds and the lack of introduction of new modes of action, many producers have turned to annual cover crops as a tool for reducing weed populations. Recent studies have suggested that perennial cover crops such as white clover could be used as living mulch. However, white clover is slow to establish and is susceptible to competition from winter weeds. Therefore, the objective of this study was to determine clover tolerance and weed control in established stands of white clover to several herbicides. Studies were conducted in the fall and winter of 2018 to 2019 and 2019 to 2020 at the J. Phil Campbell Research and Education Center in Watkinsville, GA, and the Southeast Georgia Research and Education Center in Midville, GA. POST applications of imazethapyr, bentazon, or flumetsulam at low and high rates, or in combination with 2,4-D and 2,4-DB, were applied when clover reached 2 to 3 trifoliate stage. Six weeks after the initial POST application, a sequential application of bentazon and flumetsulam individually, and combinations of 2,4-D, 2,4-DB, and flumetsulam were applied over designated plots. Clover biomass was similar across all treatments except where it was reduced by sequential applications of 2,4-D + 2,4-DB + flumetsulam in the 2019 to 2020 season indicating that most treatments were safe for use on establishing living mulch clover. A single application of flumetsulam at the low rate or a single application of 2,4-D + 2,4-DB provided the greatest control of all weed species while minimizing clover injury when compared to the non-treated check. These herbicide options allow for control of problematic winter weeds during clover establishment, maximizing clover biomass and limiting canopy gaps that would allow for summer weed emergence.


2021 ◽  
pp. 1-51
Author(s):  
Amit J. Jhala ◽  
Hugh J. Beckie ◽  
Carol Mallory-Smith ◽  
Marie Jasieniuk ◽  
Roberto Busi ◽  
...  

Abstract The objective of this paper was to review the reproductive biology, herbicide-resistant (HR) biotypes, pollen-mediated gene flow (PMGF), and potential for transfer of alleles from HR to susceptible grass weeds including barnyardgrass, creeping bentgrass, Italian ryegrass, johnsongrass, rigid (annual) ryegrass, and wild oats. The widespread occurrence of HR grass weeds is at least partly due to PMGF, particularly in obligate outcrossing species such as rigid ryegrass. Creeping bentgrass, a wind-pollinated turfgrass species, can efficiently disseminate herbicide resistance alleles via PMGF and movement of seeds and stolons. The genus Agrostis contains about 200 species, many of which are sexually compatible and produce naturally occurring hybrids as well as producing hybrids with species in the genus Polypogon. The self-incompatibility, extremely high outcrossing rate, and wind pollination in Italian ryegrass clearly point to PMGF as a major mechanism by which herbicide resistance alleles can spread across agricultural landscapes, resulting in abundant genetic variation within populations and low genetic differentiation among populations. Italian ryegrass can readily hybridize with perennial ryegrass and rigid ryegrass due to their similarity in chromosome numbers (2n=14), resulting in interspecific gene exchange. Johnsongrass, barnyardgrass, and wild oats are self-pollinated species, so the potential for PMGF is relatively low and limited to short distances; however, seeds can easily shatter upon maturity before crop harvest, leading to wider dispersal. The occurrence of PMGF in reviewed grass weed species, even at a low rate is greater than that of spontaneous mutations conferring herbicide resistance in weeds and thus can contribute to the spread of herbicide resistance alleles. This review indicates that the transfer of herbicide resistance alleles occurs under field conditions at varying levels depending on the grass weed species.


1992 ◽  
Vol 6 (3) ◽  
pp. 615-620 ◽  
Author(s):  
Jodie S. Holt

At least 57 weed species, including both dicots and monocots, have been reported to have biotypes selected for resistance to the triazine herbicides. In addition, at least 47 species have been reported to have biotypes resistant to one or more of 14 other herbicides or herbicide families. These herbicides include the aryloxyphenoxypropionics, bipyridiliums, dinitroanilines, phenoxys, substituted areas, and sulfonylureas, with two or more resistant biotypes each, as well as several other herbicides in which resistance is less well documented. Although evolved resistance presents a serious problem for chemical weed control, it has also offered new potential for transferring herbicide resistance to crop species. Mechanisms of resistance that are due to single or a few genes have become the focus of biotechnology, as the probability of their successful transfer to crop species is high.


2011 ◽  
Vol 26 (3) ◽  
pp. 193-199 ◽  
Author(s):  
A. Folgart ◽  
A. J. Price ◽  
E. van Santen ◽  
G. R. Wehtje

AbstractLegumes such as white lupin (Lupinus albus L.) provide a valuable nitrogen source in organic agriculture. With organic farming hectarage increasing and white lupin interest increasing in the southeastern USA due to newly released winter hardy cultivars, non-chemical weed control practices in lupin are needed. A two-year experiment was established at two locations in Alabama. Five weed control practices were evaluated: one pre-emergence (PRE)-applied herbicide (S-metolachlor), two mechanical (hand hoed) and two cultural (living mulch utilizing two black oat cultivars) weed control treatments. Fourteen weed species were encountered. S-metolachlor provided above 80% control of most weed species present in this experiment. The cultivation treatments and black oat companion crops also provided good weed control of many of the weeds encountered. Crop injury of all treatments was low on a 0 to 10 scale with 0 representing no injury: <2.0, <1.3 and <1.2 by S-metolachlor, the cultivation treatments and the black oat companion crops, respectively. Grain yield of cultivars ABL 1082, AU Alpha and AU Homer were 1540, 1130, 850 kg ha−1, respectively, when treated with the conventional treatment, S-metolachlor. Grain yield in the organic treatments was equivalent. The cultivation treatments and black oat companions were successful alternative weed control practices in white lupin production.


2010 ◽  
Vol 24 (4) ◽  
pp. 416-424 ◽  
Author(s):  
John C. Frihauf ◽  
Phillip W. Stahlman ◽  
Patrick W. Geier ◽  
Dallas E. Peterson

Field experiments in winter wheat were initiated at two locations in the fall of 2006 and 2007 to evaluate winter annual broadleaf weeds and winter wheat response to POST applications of two saflufenacil formulations applied alone and in combination with 2,4-D amine. Emulsifiable concentrate (EC) and water-dispersible granule (WG) formulations of saflufenacil at 13, 25, and 50 g ai ha−1were applied with 1.0% (v/v) crop oil concentrate (COC) and mixed with 2,4-D amine at 533 g ae ha−1without adjuvant. Regardless of rate or formulation, saflufenacil plus COC and saflufenacil plus 2,4-D amine controlled blue mustard ≥ 91% at 17 to 20 d after treatment (DAT) compared with ≤ 50% control with 2,4-D amine alone. At least 25 g ha−1of saflufenacil EC was necessary to control flixweed > 90%. Excluding COC from saflufenacil plus 2,4-D amine reduced flixweed control from the saflufenacil WG formulation more than the EC formulation. Most saflufenacil treatments did not control henbit satisfactorily (≤ 80%). Wheat foliar necrosis increased with increasing saflufenacil rate to as high as 30% at 3 to 6 DAT, but declined to < 15% at 10 to 20 DAT and was not evident at 30 DAT. Saflufenacil rate, formulation, and mixing with 2,4-D amine also influenced wheat stunting, but to a lesser extent than foliar necrosis. Saflufenacil EC consistently caused greater foliar necrosis and stunting on wheat than saflufenacil WG. Leaf necrosis and stunting were reduced by tank-mixing saflufenacil formulations with 2,4-D amine without COC. Grain yields of most saflufenacil treatments were similar to 2,4-D amine under weedy conditions and herbicide treatments had no effect on grain yield in weed-free experiments. Saflufenacil formulations at 25 to 50 g ha−1with 2,4-D amine and saflufenacil WG at 25 to 50 g ha−1with COC can control winter annual broadleaf weeds with minimal injury (< 15%) and no grain yield reductions. The addition of saflufenacil as a POST-applied herbicide would give wheat growers another useful tool to control annual broadleaf weeds, including herbicide-resistant weed species.


Weed Science ◽  
2014 ◽  
Vol 62 (2) ◽  
pp. 385-392 ◽  
Author(s):  
Hugh J. Beckie ◽  
Peter H. Sikkema ◽  
Nader Soltani ◽  
Robert E. Blackshaw ◽  
Eric N. Johnson

Glyphosate-resistant (GR) giant ragweed, horseweed, and common ragweed were confirmed in southwestern Ontario, Canada in 2008, 2010, and 2011, respectively. In the western prairie provinces of Alberta and Saskatchewan, GR (plus acetolactate synthase inhibitor-resistant) kochia was discovered in 2011. This symposium paper estimates the environmental impact (EI) of the top herbicide treatments or programs used to manage these GR weed species in the major field crops grown in each region. For each herbicide treatment, EI (per ha basis) was calculated as the environmental impact quotient (EIQ), which quantifies the relative potential risk of pesticide active ingredients on human and ecological health based on risk components to farm workers, consumers, and the environment, multiplied by the application rate (kg ai ha−1). Total EI is defined as EI (per ha basis) multiplied by the application area (i.e., land area affected by a GR weed). It was assumed that all herbicide treatments would supplement the continued usage of glyphosate because of its broad spectrum weed control. For the control of these GR weeds, most treatments contain auxinic or protoporphyrinogen oxidase (PPO)-inhibiting herbicides. The majority of auxinic herbicide treatments result in low (EI ≤ 10) to moderate (11 to 20) EI, whereas all treatments of PPO inhibitors have low EI. Total EI of GR horseweed and kochia will generally be greater than that of giant or common ragweed because of rapid seed dispersal. For recommended herbicide treatments to control GR weeds (and herbicide-resistant weeds in general), EI data should be routinely included with cost and site of action in weed control extension publications and software, so that growers have the information needed to assess the EI of their actions.


2017 ◽  
Vol 44 (2) ◽  
pp. 93-99 ◽  
Author(s):  
O.W. Carter ◽  
E.P. Prostko ◽  
J.W. Davis

ABSTRACT The increase in herbicide-resistant weeds over the past decade has led to the introduction of crops that are resistant to auxin herbicides. Strict application procedures are required for the use of auxin herbicides in auxin-resistant crops to minimize off-target movement. One requirement for application is the use of nozzles that will minimize drift by producing coarse droplets. Generally, an increase in droplet size can lead to a reduction in coverage and efficacy depending upon the herbicide and weed species. In studies conducted in 2015 and 2016, two of the potential required auxin nozzle types [(AIXR11002 (coarse) and TTI11002 (ultra-coarse)] were compared to a conventional flat-fan drift guard nozzles [DG11002 (medium)] for weed control in peanut herbicide systems. Nozzle type did not influence annual grass or Palmer amaranth control in non-crop tests. Results from in-crop tests indicated that annual grass control was 5% to 6% lower when herbicides were applied with the TTI nozzle when compared to the AIXR or DG nozzles. However, Palmer amaranth control and peanut yield was not influenced by coarse-droplet nozzles. Peanut growers using the coarse-droplet nozzles need to be aware of potential reduced grass control.


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