The response of glyphosate-resistant and glyphosate-susceptible biotypes of annual sowthistle (Sonchus oleraceus) to mungbean density

Weed Science ◽  
2019 ◽  
Vol 67 (6) ◽  
pp. 642-648 ◽  
Author(s):  
Ahmadreza Mobli ◽  
Amar Matloob ◽  
Bhagirath Singh Chauhan
Keyword(s):  
Seed Production ◽  
Weed Management ◽  
Vigna Radiata ◽  
Competitive Ability ◽  
Management Strategies ◽  
Stand Density ◽  
Sonchus Oleraceus ◽  
Crop Density ◽  
Crop Stand ◽  
Number Of Seeds

AbstractAnnual sowthistle (Sonchus oleraceus L.) is a major weed of mungbean crops in Australia. Resistance in this weed to several herbicide groups is a challenging issue for its management. Hence, cultural weed management strategies, such as increasing the crop competitive ability through increased stand density, should be considered to reduce reliance on herbicides. It was hypothesized that a competitive crop stand may reduce the growth and seed production of S. oleraceus. Two pot studies were conducted, and each study was repeated once. The first study evaluated the effect of different mungbean [Vigna radiata (L.) R. Wilczek] densities (0, 82, 164, 246, and 328 plants m−2) on S. oleraceus growth and seed production, while the second study focused on glyphosate-resistant and glyphosate-susceptible biotypes of this weed in competition with densities of 0, 82, and 164 mungbean plants m−2. Although increasing mungbean density from 0 to 82 and 164 plants m−2 reduced S. oleraceus seed production by 55% and 78%, respectively, a large number of seeds were produced, even at the mungbean density of 328 plants m−2 (1,185 seeds plant−1). Both glyphosate-resistant and glyphosate-susceptible biotypes of S. oleraceus responded similarly to the increase in mungbean density. The results of the second study showed that height, leaves, number of inflorescence, and seed production per plant of both glyphosate-resistant and glyphosate-susceptible biotypes were reduced but not suppressed adequately. The glyphosate-resistant biotype produced fewer leaves and less biomass and, consequently, its seed production was 24% less compared with the glyphosate-susceptible biotype in the no-competition treatment. Both biotypes of S. oleraceus produced about 4,000 seeds plant−1 in competition with 164 mungbean plants m−2. The results suggest that crop competition alone cannot provide satisfactory control of S. oleraceus; therefore, for effective and adequate weed management, other practices such as PRE herbicides should be integrated with increased crop density.

Emergence timing affects growth and reproduction of goosegrass (Eleusine indica)

2019 ◽  
Vol 33 (6) ◽  
pp. 833-839
Author(s):  
Xiaoyan Ma ◽  
Yajie Ma ◽  
Hanwen Wu ◽  
Xiangliang Ren ◽  
Weili Jiang ◽  
...  
Keyword(s):  
Seed Production ◽  
Weed Management ◽  
Field Experiments ◽  
Soil Seed Bank ◽  
Management Strategies ◽  
Reproductive Investment ◽  
Average Weight ◽  
June July ◽  
Number Of Seeds ◽  
Growth And Reproduction

AbstractGoosegrass is considered one of the worst agricultural weeds worldwide. Understanding its life cycle will provide useful management information. Field experiments with six emergence times (April, May, June, July, August, and September) were conducted at Anyang, China in 2015 and 2017 to clarify the growth and reproduction of goosegrass emerging at different times within a season. The result showed that plant height, dry weight, average weight per inflorescence, total inflorescence weight, average seed number per inflorescence, and total number of seeds per plant were relatively low in the April cohort, peaked with the May or June emergence cohort, and decreased thereafter. However, the earliest emergence of goosegrass in April had the highest total number of inflorescences. The plants of the May cohort produced the greatest number of seeds: 225,954 and 322,501 seeds per plant in 2015 and 2017, respectively. Delayed emergence resulted in less seed production; most plants that emerged in September did not flower or set seed. The 1,000-seed weight did not vary among the emergence cohorts. The reproductive investment was lowest for plants of the May cohort and then increased as emergence time was delayed to June, July, and August. Fresh mature seed of all emergence cohorts was extremely dormant and had low germination only up to 6% from August to November, and high germination (44% to 93%) in December. The information gained from this study indicates that weed management strategies should focus on the early-emerged seedlings such as the April and May cohorts, so as to effectively prevent goosegrass seed production, minimize the weed seed replenishment into the soil seed bank, and reduce the infestation in subsequent seasons.

scholarly journals Effects of Palmer Amaranth (Amaranthus palmeri) Establishment Time and Distance from the Crop Row on Biological and Phenological Characteristics of the Weed: Implications on Soybean Yield

Weed Science ◽  
2019 ◽  
Vol 67 (1) ◽  
pp. 126-135 ◽  
Author(s):  
Nicholas E. Korres ◽  
Jason K. Norsworthy ◽  
Andy Mauromoustakos
Keyword(s):  
Seed Production ◽  
Weed Management ◽  
Cropping Systems ◽  
Management Strategies ◽  
Palmer Amaranth ◽  
Yield Reduction ◽  
Amaranthus Palmeri ◽  
Soybean Yield ◽  
Management Measures ◽  
Weed Population Dynamics

AbstractInformation about weed biology and weed population dynamics is critical for the development of efficient weed management programs. A field experiment was conducted in Fayetteville, AR, during 2014 and 2015 to examine the effects of Palmer amaranth (Amaranthus palmeriS. Watson) establishment time in relation to soybean [Glycine max(L.) Merr.] emergence and the effects ofA. palmeridistance from the soybean row on the weed’s height, biomass, seed production, and flowering time and on soybean yield. The establishment time factor, in weeks after crop emergence (WAE), was composed of six treatment levels (0, 1, 2, 4, 6, and 8 WAE), whereas the distance from the crop consisted of three treatment levels (0, 24, and 48 cm). Differences inA. palmeribiomass and seed production averaged across distance from the crop were found at 0 and 1 WAE in both years. Establishment time had a significant effect onA. palmeriseed production through greater biomass production and height increases at earlier dates.Amaranthus palmerithat was established with the crop (0 WAE) overtopped soybean at about 7 and 10 WAE in 2014 and 2015, respectively. Distance from the crop affectedA. palmeriheight, biomass, and seed production. The greater the distance from the crop, the higherA. palmeriheight, biomass, and seed production at 0 and 1 WAE compared with other dates (i.e., 2, 4, 6, and 8 WAE).Amaranthus palmeriestablishment time had a significant impact on soybean yield, but distance from the crop did not. The earlierA. palmeriinterfered with soybean (0 and 1 WAE), the greater the crop yield reduction; after that period no significant yield reductions were recorded compared with the rest of the weed establishment times. Knowledge ofA. palmeriresponse, especially at early stages of its life cycle, is important for designing efficient weed management strategies and cropping systems that can enhance crop competitiveness. Control ofA. palmeriwithin the first week after crop emergence or reduced distance between crop and weed are important factors for an effective implementation of weed management measures againstA. palmeriand reduced soybean yield losses due to weed interference.

Management of Avena ludoviciana and Phalaris paradoxa with barley and less herbicide in subtropical Australia

2001 ◽  
Vol 41 (8) ◽  
pp. 1179 ◽  
Author(s):  
S. R. Walker ◽  
G. R. Robinson ◽  
R. W. Medd
Keyword(s):  
Seed Production ◽  
Weed Management ◽  
Field Experiments ◽  
Management Strategies ◽  
Maximum Yield ◽  
Yield Reduction ◽  
Weed Seed ◽  
Tiller Density ◽  
Weed Emergence ◽  
Subtropical Australia

The competitive advantage of barley compared with wheat was quantified for suppressing seed production of Avena ludoviciana Durieu. (wild oats) andPhalaris paradoxa L. (paradoxa grass), and for improving herbicide effectiveness on these major winter grass weeds of the subtropical grain region of Australia. Eight field experiments were broadcast with weed seed before sowing wheat or barley, in which the emerged weeds were then treated with 4 herbicide doses (0, 25, 50, 100% of recommended rates). Yield reduction from untreated weeds was on average 4 times greater in wheat than in barley, with greater losses from A. ludoviciana than P. paradoxa. Barley did not affect weed emergence, but suppressed weed tiller density and, to a lesser extent, the number of weed seeds per tiller. Seed production was, on average, 4340 and 5105 seeds/m2 for A. ludoviciana and P. paradoxa, respectively, in untreated wheat compared with 555 and 50 seeds/m2 in untreated barley. Weed seed production following treatment with 25% herbicide rate in barley was similar or less than that after treatment with 100% herbicide rate in wheat. Overall, 25% herbicide rate was optimal for both conserving yield and minimising weed seed production in barley. For wheat, maximum yield was achieved with 50% herbicide but weed seed production was lowest with 100% herbicide rate. This indicates that weeds can be effectively controlled in barley with considerably less herbicide than required in wheat, highlighting the importance of including barley as a part of weed management strategies that aim to reduce herbicide inputs.

Influence of corn (Zea mays) population and row spacing on corn and velvetleaf (Abutilon theophrasti) yield

Weed Science ◽  
1998 ◽  
Vol 46 (4) ◽  
pp. 447-453 ◽  
Author(s):  
John R. Teasdale
Keyword(s):  
Seed Production ◽  
Weed Management ◽  
Management Strategies ◽  
Light Availability ◽  
Integrated Weed Management ◽  
Row Spacing ◽  
Corn Yield ◽  
Corn Production ◽  
One Year ◽  
Reduced Light

Research was conducted to determine the optimum population and row spacing for corn production and for suppressing velvetleaf growth and seed production. Corn was grown in a factorial arrangement of three populations targeted at 64,000 (1 ×), 96,000 (1.5 ×), or 128,000 (2 ×) plants ha−1and two row spacings of 38 or 76 cm. Influences on corn were determined in weed-free plots, and influences on velvetleaf were determined for target plants established at 1.5–m intervals along the center of corn interrows. Four velvetleaf plantings were made at weekly intervals beginning at corn planting. Corn row spacing had little influence on corn or velvetleaf. Corn yield exhibited a parabolic response to population with a maximum of approximately 90,000 plants ha−1in one year, no response to population in another year, and a linear decline with increasing population in a dry year. Velvetleaf seed production was reduced 69 to 94% by the 1.5 × population and 99% by the 2 × population compared to the standard 1 × population when velvetleaf emerged with corn. Velvetleaf seed production was eliminated when velvetleaf emerged at or later than corn leaf stages 3, 5, and 6 for corn populations of 2 ×, 1.5 ×, and 1 ×, respectively. Reduced velvetleaf seed production was correlated with lower positioning of plants in the corn canopy and reduced light availability. Results suggest that higher corn populations could aid integrated weed management strategies by reducing seed production and limiting the build-up of weed populations.

scholarly journals The Impact of Herbicide Application and Defoliation on Barley Grass (Hordeum murinum subsp. glaucum) Management in Mixed Pasture Legumes

Agronomy ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 671
Author(s):  
Jane Kelly ◽  
Allison Chambers ◽  
Paul Weston ◽  
William Brown ◽  
Wayne Robinson ◽  
...  
Keyword(s):  
Seed Production ◽  
Weed Management ◽  
Seedling Emergence ◽  
Management Strategies ◽  
Biomass Accumulation ◽  
Integrated Weed Management ◽  
Wagga Wagga ◽  
Weed Biomass ◽  
Hordeum Murinum ◽  
The Impact

Barley grass (Hordeum murinum subsp. glaucum.) is an annual weed associated with grain revenue loss and sheep carcass damage in southern Australia. Increasing herbicide resistance led to a recent investigation into effective integrated weed management strategies for barley grass in southern Australia. Field studies in Wagga Wagga, New South Wales (NSW) during 2016 and 2017 examined the effect of post-emergent herbicide applications and strategic defoliation by mowing on barley grass survival and seed production in a mixed legume pasture. Statistically significant differences between herbicide-only treatments in both years showed propaquizafop to be more than 98% effective in reducing barley grass survival and seed production. Paraquat was not effective in controlling barley grass (58% efficacy), but led to a 36% and 63.5% decrease in clover and other weed biomass, respectively, after 12 months and increased lucerne biomass by over three-fold after 24 months. A single repeated mowing treatment resulted in a 46% decline in barley grass seedling emergence after 12 months and, when integrated with herbicide applications, reduced other weed biomass after 24 months by 95%. Resistance to acetyl-CoA carboxylase (ACCase)-inhibiting herbicides observed in local barley grass populations led to additional and more focused investigation comparing the efficacy of other pre- and post-emergent herbicides for barley grass management in legume pastures. Haloxyfop-R + simazine or paraquat, applied at early tillering stage, were most efficacious in reducing barley grass survival and fecundity. Impact of defoliation timing and frequency on barley grass seedlings was also evaluated at various population densities, highlighting the efficacy of repeated post-inflorescence defoliations in reducing plant survival and seed production. Results highlight the importance of optimal environmental conditions and application timing in achieving efficacious control of barley grass and improving pasture growth and biomass accumulation.

Crop stand density enhances competitive ability of spring barley (Hordeum vulgareL.)

2011 ◽  
Vol 61 (7) ◽  
pp. 648-660 ◽  
Author(s):  
Vytautas Pilipavicius ◽  
Regina Romaneckiene ◽  
Kestutis Romaneckas
Keyword(s):  
Competitive Ability ◽  
Spring Barley ◽  
Stand Density ◽  
Crop Stand

Integrated Management of Scotch Broom (Cytisus scoparius) Using Biological Control

2012 ◽  
Vol 5 (1) ◽  
pp. 69-82 ◽  
Author(s):  
Angelica M. Herrera-Reddy ◽  
Raymond I. Carruthers ◽  
Nicholas J. Mills
Keyword(s):  
Biological Control ◽  
Seed Production ◽  
Seed Bank ◽  
Weed Management ◽  
Biological Control Agent ◽  
Integrated Management ◽  
Management Strategies ◽  
Integrated Weed Management ◽  
Scotch Broom ◽  
Mature Seeds

AbstractIntegrated weed management strategies (IWM) are being advocated and employed to control invasive plants species. In this study, we compared three management strategies (biological control alone [BC], BC with fire [BC + F], and BC with mowing [BC + M]) to determine if physical controls reduce seed production by Scotch broom and interfere with the action of the biological control agent—the Scotch broom seed weevil. We measured seed production and seed predation by the weevil at both pod and plant scale, and seed bank density over two field seasons. We found no difference in the number of seeds per pod among management strategies. However, combining management strategies (BC + M and BC + F) resulted in significant reductions in pods per plant, mature seeds per plant, and seed bank density relative to biological control alone. We did not find differences among management strategies in number of weevils per pod or proportion of seeds predated by the weevil at either pod or whole-plant scale. However, combining management strategies (BC + M and BC + F) resulted in a significant reduction in healthy mature seeds per plant relative to biological control alone. Although both integrated strategies outperformed biological control alone in reducing seed production and the seed bank, with no statistical difference between them, we propose that short-rotation prescribed fire could prove to be a more effective strategy for long-term management of Scotch broom due to its potential for slightly greater depletion of the seed bank.

Manipulation of sunflower population density and herbicide rate for economical and sustainable weed management

2021 ◽  
Vol 26 (4) ◽  
pp. 2751-2758
Author(s):  
EDITA ŠTEFANIĆ ◽  
SLAVICA ANTUNOVIĆ ◽  
BOŽICA JAPUNDŽIĆ-PALENKIĆ ◽  
DINKO ZIMA
Keyword(s):  
Population Density ◽  
Weed Control ◽  
Crop Yield ◽  
Weed Management ◽  
Management Strategies ◽  
Control Efficacy ◽  
Economic Return ◽  
Crop Density ◽  
Herbicide Treatments ◽  
Weed Infestation

Field study tested weed control efficacy, crop yield and economic return using various weed management strategies in sunflower growing with different population density. Treatments included four rates of PRE emergence application of S-metolachlor + fluchloridon and one POST emergence application of flumioxazin + quizalofop-pethyl. PRE-em application (1.4 + 2.4 and 1.2 + 2.0) provided at the higher crop densities (70 000) best weed control. However, PRE- em treatments with lower doses (0.8 + 1.6 and 1.0 + 1.8) and POST- em application did not maintain acceptable control of dominant weeds. Grain yield increased with the crop density, but did not statistically differ between applied herbicide treatments. Finally, the implication of this study demonstrated that sole application of tested herbicide treatments at higher crop sowing density (60 000 and 70 000) was found to be economically the best alternative strategy for reducing weed infestation and achieving a better yield.

Weed Thresholds: The Space Component and Considerations for Herbicide Resistance

1992 ◽  
Vol 6 (1) ◽  
pp. 205-212 ◽  
Author(s):  
Bruce D. Maxwell
Keyword(s):  
Herbicide Resistance ◽  
Weed Management ◽  
Competitive Ability ◽  
Management Strategies ◽  
Agricultural Practices ◽  
Cereal Crops ◽  
Weed Population ◽  
Weed Density ◽  
Population Frequency ◽  
Selection For

As an extension of weed threshold models in which crop losses are based on weed density, an alternative model for grass weeds in cereal crops is proposed that incorporates the theoretical importance of selection for herbicide resistance, initial weed population frequency, and weed seed dispersal. Simulations suggest optimum weed population levels (thresholds) for maintaining genotypes that are susceptible to control practices and which minimize crop yield reductions. Weed population frequency, in combination with dispersal and competitive traits may determine optimum weed management strategies/Model simulations indicate that understanding how agricultural practices select for “weedy” traits (e.g. herbicide resistance, competitive ability, dispersal potential) may be important in determining weed density thresholds.

scholarly journals Allelopathic Inhibition of Nitrifying Bacteria by Legumes

2017 ◽  
Vol 22 (2) ◽  
pp. 125-130
Author(s):  
Uum Umiyati
Keyword(s):  
Weed Management ◽  
Vigna Radiata ◽  
Competitive Ability ◽  
Block Design ◽  
Nitrifying Bacteria ◽  
Mucuna Pruriens ◽  
Organic N ◽  
Available Nitrogen ◽  
N Content ◽  
Randomized Block Design

The study aimed at understanding the competitive ability of legumes Vigna radiata L. and Mucuna pruriens with weeds and their effects on the activity of nitrifying bacteria in soils and the contents of organic-N in legumes and weeds. The experiment was arranged in a randomized block design with three factors and four replications. The first factor was soil order, i.e. Inceptisol and Vertisol; the second factor was types of legumes, i.e. Vigna radiata L. cultivar Sriti and Mucuna pruriens; and the third factor was weed management, i.e. with weed management and without weed management. The results showed that Vigna radiata L. and Mucuna pruriens indirectly influence the supply of available nitrogen in soils that can be taken up by the coexisted plants or weeds via the inhibition of the growth of Nitrosomonas and Nitrobacter in soils. As a results, the organic-N content in weeds decreases, which is in contrast to the increasing amount of organic-N in Vigna radiata L. and Mucuna pruriens. The results indicated that Vigna radiata L. and Mucuna pruriens are considered as allelophatic legumes, resulting in low organic-N content in weeds.  Keywords: Allelopathic, Mucuna pruriens, Nitrosomonas, Nitrobacter, Vigna radiata 

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