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

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.

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Seed production and seedbank dynamics in subthreshold velvetleaf (Abutilon theophrasti) populations

Weed Science ◽

10.1017/s0043174500092511 ◽

1997 ◽

Vol 45 (1) ◽

pp. 85-90 ◽

Cited By ~ 26

Author(s):

John Cardina ◽

Heather M. Norquay

Keyword(s):

Pest Management ◽

Seed Production ◽

Weed Management ◽

Seedling Emergence ◽

Seed Rain ◽

Abutilon Theophrasti ◽

No Tillage ◽

Single Seed ◽

No Till ◽

The Impact

The impact of seed production by subthreshold weed populations on future weed problems has impeded the adoption of integrated pest-management principles for weed management. Studies were conducted in fields with no velvetleaf history to determine how seedbanks and seedling populations change following seed production 1 yr or 5 consecutive yr in plow-disk and no-tillage corn. Cumulative seed production by 0.19 velvetleaf plants m−2increased in a linear fashion from 1989 to 1994, with annual additions averaging from 330 seeds m−2for velvetleaf in corn to 2,500 seeds m−2for velvetleaf without competition from corn. Five-year cumulative seed production was 1,480 seeds m−2in plow-disk and 1,810 seeds m−2in no-till corn. In no-till corn, 42 velvetleaf seedlings m−2emerged the 1st year after the 1989 seed rain, but only 35 seedlings m−2emerged over the next 4 yr. In plow-disk plots, annual emergence averaged 12 seedlings m−2. Five years after the 1989 seed rain, the proportion of seeds lost to emergence was about 20% in both tillage treatments. Where velvetleaf seeds were allowed to return to the soil every year, cumulative seedling emergence was lower in plow-disk than in no-till corn, with total emergence of 70 and 360 seedlings m−2, respectively, after 5 yr. Seedbank numbers ranged from 10 seeds m−25 yr after a single seed rain (290 seeds m−2) by velvetleaf in plow-disk corn to 1,020 seeds m−2following 5 consecutive yr of seed rain where 12,580 seeds m−2were returned without corn competition in no-till. Seedbank samples in the fall of the 5th year had 69 to 98% fewer seeds than were accounted for by cumulative seed rain and seedling emergence, with greater apparent seed losses in plow-disk corn than in no-till corn. Over 90% velvetleaf control would be required annually to maintain subthreshold populations for 5 yr following a single seed rain. By comparison, over 95% control would be required annually to maintain subthreshold populations where velvetleaf seed return is permitted each year.

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Seed Germination, Seedling Emergence, and Response to Herbicides of Triquetrous Murdannia (Murdannia triquetra) in Rice

Weed Science ◽

10.1614/ws-d-16-00048.1 ◽

2016 ◽

Vol 65 (1) ◽

pp. 141-150 ◽

Cited By ~ 2

Author(s):

Wei Tang ◽

Jie Chen ◽

Jianping Zhang ◽

Yongliang Lu

Keyword(s):

Seed Germination ◽

Weed Management ◽

Seedling Emergence ◽

Management Strategies ◽

Soil Surface ◽

Rice Fields ◽

Integrated Weed Management ◽

Burial Depth ◽

Nacl Concentration ◽

Dark Regime

Triquetrous murdannia is an annual weed commonly found in rice fields in China. Laboratory and screenhouse experiments were carried out to determine the effect of light, temperature, osmotic and salt stress, seed burial depth, amount of rice residue, and depth of flooding on seed germination and seedling emergence of triquetrous murdannia and to evaluate the response of this weed to commonly available POST herbicides in China. Germination was greater than 93% under a wide day/night temperature range of 20/10 to 30/20 C in the light/dark regime. The time to onset of germination decreased as temperature increased. Germination was slightly stimulated when seeds were placed in light/dark conditions compared with seeds placed in the dark. The osmotic potential and NaCl concentration required for 50% inhibition of maximum germination were −0.5 MPa and 122 mM, respectively. The highest germination (68%) was observed from seeds sown on the soil surface, but decreased with increasing burial depth. Only 7% of seedlings emerged from a depth of 4 cm, and no seedlings emerged from seeds buried deeper than 6 cm. Seedling emergence decreased from 93 to 35% with increasing quantity of rice residue (1 to 6 103kg ha−1) applied on the soil surface. Seedling emergence was reduced by 40, 48, 64, and 70% at flooding depths of 1, 2, 4, and 6 cm, respectively, for the seeds sown on the soil surface. Fluroxypyr and MCPA herbicides provided 100% control of triquetrous murdannia at the 2- to 6-leaf stages; however, to achieve 100% control with bispyribac-sodium, MCPA+bentazone or MCPA+fluroxypyr, herbicides had to be applied by the 4-leaf stage. The results of this study could help in developing more sustainable and effective integrated weed management strategies for the control of triquetrous murdannia in rice fields in China.

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

Weed Science ◽

10.1017/s0043174500090883 ◽

1998 ◽

Vol 46 (4) ◽

pp. 447-453 ◽

Cited By ~ 52

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.

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

Invasive Plant Science and Management ◽

10.1614/ipsm-d-11-00048.1 ◽

2012 ◽

Vol 5 (1) ◽

pp. 69-82 ◽

Cited By ~ 13

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.

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Effect of Crop Residue on Seedling Emergence and Growth of Selected Weed Species in a Sprinkler-Irrigated Zero-Till Dry-Seeded Rice System

Weed Science ◽

10.1614/ws-d-12-00147.1 ◽

2013 ◽

Vol 61 (3) ◽

pp. 403-409 ◽

Cited By ~ 15

Author(s):

Bhagirath S. Chauhan ◽

Seth B. Abugho

Keyword(s):

Field Study ◽

Weed Control ◽

Weed Management ◽

Crop Residue ◽

Crop Residues ◽

Seedling Emergence ◽

Management Strategies ◽

Weed Species ◽

Weed Biomass ◽

Residue Retention

Crop residues acting as mulches can influence weed seedling emergence and weed biomass. A field study was conducted to evaluate the effect of rice residue amounts (0, 3, and 6 t ha−1) on seedling emergence of eight weed species in zero-till dry-seeded rice. The highest seedling emergence of spiny amaranth, southern crabgrass, crowfootgrass, junglerice, eclipta, goosegrass, and Chinese sprangletop was observed in the absence of residue. Seedling emergence of these weeds declined with increasing residue amounts; however, the greatest and most substantial reductions in emergence occurred with 6 t ha−1of residue. The presence of residue also resulted in less weed biomass than with the no-residue treatment. The emergence and biomass of threelobe morningglory seedlings, however, were not influenced by residue amounts. The use of residue also increased the time taken to reach 50% of maximum emergence for some species, for example, spiny amaranth and Chinese sprangletop. The results of our study suggest that the use of residue at high rates can help suppress seedling emergence and growth of many weeds. However, there is a need to integrate other weed management strategies with residue retention to achieve season-long weed control.

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Seed Germination Ecology of Doveweed (Murdannia nudiflora)and Its Implication for Management in Dry-Seeded Rice

Weed Science ◽

10.1614/ws-d-14-00115.1 ◽

2015 ◽

Vol 63 (2) ◽

pp. 491-501 ◽

Cited By ~ 20

Author(s):

Sharif Ahmed ◽

Jhoana L. Opeña ◽

Bhagirath S. Chauhan

Keyword(s):

Weed Management ◽

Crop Residues ◽

Seedling Emergence ◽

Management Strategies ◽

Soil Surface ◽

Integrated Weed Management ◽

Burial Depth ◽

Similar Response ◽

Leaf Stage ◽

Dark Regime

This study was conducted in the laboratory and screenhouse to determine the effects of temperature, light, osmotic stress, salt stress, burial depth, use of crop residues as mulch, depth of flooding, and use of POST herbicides on the emergence, survival, and growth of doveweed. In the light/dark regime, germination was higher at alternating day/night temperatures of 35/25 C (95%) than at 30/20 C (72%), and no germination occurred at 25/15 C. Light strongly influenced germination (95%) and dark completely inhibited germination. No germination occurred at an osmotic potential of −0.8 MPa and a salt concentration of 150 mM and above. The highest germination (91%) was observed from the seeds sown on the soil surface and emergence decreased by 78, 86, and 92% when burial depths were increased to 0.5, 1, and 2 cm, respectively. No seedlings emerged from seeds buried at depths of more than 2 cm. The use of rice residues as mulch significantly reduced the emergence and growth of doveweed seedlings. The amount of residue required to suppress 50% of the maximum biomass was 2.5 t ha−1. Flooding had a more pronounced effect on seedling biomass than seedling emergence. Biomass was reduced by 78, 92, and 96% when flooding depths increased from 0 to 2, 4, and 6 cm, respectively, for the seeds placed on the soil surface, whereas for the seeds buried at 0.5 cm, these values were 78, 100, and 100%. Bentazon (100 g ha−1) and bispyribac-sodium (30 g ha−1) provided 100% control of doveweed when applied at the three-leaf stage. Doveweed control was less than 31% with glyphosate rates up to 2,000 g ha−1. The application of 2,4-D (500 g ha−1) provided 100% control of doveweed even when applied at the seven-leaf stage. The information from this study could help in developing more sustainable and effective integrated weed management strategies for the control of this weed and weeds with similar response in dry-seeded rice systems.

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Crowfootgrass (Dactyloctenium aegyptium) Germination and Response to Herbicides in the Philippines

Weed Science ◽

10.1614/ws-d-11-00048.1 ◽

2011 ◽

Vol 59 (4) ◽

pp. 512-516 ◽

Cited By ~ 15

Author(s):

Bhagirath Singh Chauhan

Keyword(s):

Seed Germination ◽

Weed Management ◽

Seedling Emergence ◽

Management Strategies ◽

Soil Surface ◽

The Philippines ◽

Integrated Weed Management ◽

Burial Depth ◽

Early Application ◽

Dark Regime

Crowfootgrass, a C4species, is one of the principal weeds of dry-seeded rice in Asia. Weed management decisions for this species can be derived from knowledge of its seed germination biology. Experiments were conducted in the laboratory and screenhouse to determine the effects of light, alternating day/night temperatures, water stress, seed burial depth, and rice residue on seed germination and seedling emergence of crowfootgrass and to evaluate the response of this weed to commonly available selective POST herbicides in the Philippines. Light stimulated seed germination, but it was not an absolute requirement for germination. Germination in the light/dark regime was greater at alternating day/night temperatures of 25/15 C (92%) than at 30/20 (70%) or 35/25 C (44%). The osmotic potential required for 50% inhibition of maximum germination was −0.23 MPa, although some seeds germinated at −0.6 MPa. Seedling emergence was greatest for the seeds placed on the soil surface (64%), and emergence declined with increased burial depth in soil. No seedlings emerged from a burial depth of 6 cm or greater. Seedling emergence of crowfootgrass was reduced by the addition of rice residue to the soil surface at rates equivalent to 4 to 6 Mg ha−1. Fenoxaprop-p-ethyl + ethoxysulfuron at 45 g ai ha−1provided excellent control of crowfootgrass when applied at the four- (99%) and six-leaf (86%) stage. The information gained from this study could contribute to developing components of integrated weed management strategies for crowfootgrass. Soil inversion by tillage to bury weed seeds below their maximum depth of emergence, use of crop residue as mulch, and early application of an effective POST herbicide could serve as important tools for managing crowfootgrass.

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Optimisation of Weed Control in Organic Processing Spinach (Spinacia oleracea L.): Impacts of Cultivar, Seeding Rate, Plant Spacing and Integrated Weed Management Strategy

Agronomy ◽

10.3390/agronomy11010053 ◽

2020 ◽

Vol 11 (1) ◽

pp. 53

Author(s):

Benny De Cauwer ◽

Lieven Delanote ◽

Michaël Devos ◽

Sander De Ryck ◽

Dirk Reheul

Keyword(s):

Growth Rate ◽

Weed Control ◽

Weed Management ◽

Management Strategy ◽

Growth Habit ◽

Integrated Weed Management ◽

Plant Spacing ◽

Seeding Rate ◽

Weed Biomass ◽

The Impact

Weed control in organic spinach for the processing market is challenging because of the low tolerance of weed contamination in the harvested produce and the limited physical weeding options. Optimisation of weed control systems is therefore urgently needed. Three field experiments with autumn spinach were carried out in organic fields to evaluate the impact of cultivar choice, seeding rate (300 and 400 seeds m−2), plant spacing management (10.5-cm-wide single rows and 21-cm-wide single or twin rows) and integrated weed management strategy (combinations of pre-sowing, pre-emergence and post-emergence tactics) on weed biomass and spinach yield and quality. Spinach cultivars with a planophile growth habit and a high growth rate were more weed suppressive than the cultivar with an erectophile growth habit and a slower growth rate. Spinach density was significantly negatively correlated with weed biomass and weed biomass fraction in the harvested produce, but significantly positively correlated with (marketable) spinach biomass and petiole fraction in the harvested produce. Narrow row spacing systems with post-emergence broadcast harrowing had the lowest weed biomass and weed biomass fraction but also the lowest (marketable) spinach biomass as a result of the thinning action of harrowing. Post-emergence harrowing is of key importance for reducing weed biomass in any integrated weed control strategy. Weediness was lowest in systems comprising flaming on false seedbed or in pre-emergence followed by post-emergence harrowing. To mitigate the risk of crop failure, the field should preferably be cropped with quickly growing spinach plants arranged in narrow spaced rows at high plant density and weeded by pre-sowing or pre-emergence flaming followed by post-emergence harrowing.

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Seed production and retention at maturity of blackgrass (Alopecurus myosuroides) and silky windgrass (Apera spica-venti) at wheat harvest

Weed Science ◽

10.1017/wsc.2020.7 ◽

2020 ◽

Vol 68 (2) ◽

pp. 151-156 ◽

Cited By ~ 4

Author(s):

Zahra Bitarafan ◽

Christian Andreasen

Keyword(s):

Seed Production ◽

Weed Management ◽

Management Strategies ◽

Reproductive Development ◽

Integrated Weed Management ◽

Herbicide Resistant ◽

Alopecurus Myosuroides ◽

Soil Seedbank ◽

Crop Harvest ◽

Total Seed

AbstractBlackgrass (Alopecurus myosuroides Huds.) and silky windgrass [Apera spica-venti (L.) P. Beauv.] are becoming a significant problem in Europe. Due to the development of herbicide-resistant biotypes and unwanted side effects of herbicides, there is a need for new integrated weed management strategies to control weeds. Therefore, reducing weed infestations by targeting seed production during crop harvest should be considered. In 2017 and 2018, we estimated the fraction of the total seed production of A. myosuroides and A. spica-venti in a field that potentially could be collected by a grain harvester during winter wheat (Triticum aestivum L.) harvest. Twenty plants of each species were surrounded by a porous net before flowering to trap shed seeds during reproductive development. Seeds were collected and counted weekly up until and immediately before wheat harvest, and the ratio of harvestable seeds to shed seeds during the growing season was determined. Alopecurus myosuroides produced on average 953 seeds plant−1 in 2017 and 3,337 seeds plant−1 in 2018. In 2017 and 2018, 29% and 37% of the total A. myosuroides seeds produced, respectively, were retained on plants at maturity. Apera spica-venti produced on average 1,192 seeds plant−1 in 2017 and 5,678 seeds plant−1 in 2018, and retained 53% and 16% of the seeds at harvest, respectively. If a grain harvester potentially collected approximately 30% of the total seed production of the two grass weeds and removed or killed them, it would reduce seed input to the soil seedbank. However, such methods cannot stand alone to reduce weed pressure.

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Weed management in direct seeded rice: A review

Agricultural Reviews ◽

10.18805/ag.v0iof.7307 ◽

2017 ◽

Cited By ~ 1

Author(s):

Sheeja K Raj ◽

Elizabeth K Syriac

Keyword(s):

Weed Control ◽

Weed Management ◽

Sustainable Management ◽

Critical Period ◽

Seedling Emergence ◽

Management Strategies ◽

Integrated Weed Management ◽

Weed Flora ◽

Direct Seeded

Weeds are the major biological constraint in direct seeded rice (DSR) due to the concurrent emergence of competitive weeds, absence of water to suppress weeds at the time of seedling emergence and emergence of difficult to control weeds. Strategies on weed management in direct seeded rice depend on critical period of weed control, weed flora and method to be adopted. In order to achieve the long term and sustainable management of weeds in DSR an integration of different weed management strategies like integrated weed management (IWM) are essential. The literature regarding the critical period of weed control, weed flora and different methods for the sustainable management of weeds in direct seeded rice are reviewed in this paper.

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