Evaluating Seed Shatter of Economically Important Weed Species

Weed Science ◽  
2016 ◽  
Vol 64 (4) ◽  
pp. 673-682 ◽  
Author(s):  
Nikki R. Burton ◽  
Hugh J. Beckie ◽  
Christian J. Willenborg ◽  
Steven J. Shirtliffe ◽  
Jeff J. Schoenau ◽  
...  
Keyword(s):  
Weed Management ◽  
Field Experiments ◽  
Management Strategies ◽  
Wild Oat ◽  
Population Abundance ◽  
Weed Seed ◽  
Weed Species ◽  
Wild Mustard ◽  
Green Foxtail ◽  
Crop Maturity

The increasing occurrence of herbicide resistance, along with no new herbicide modes of action developed in over 30 yr, have increased the need for nonherbicidal weed management strategies and tactics. Harvest weed seed control (HWSC) practices have been successfully adopted in Australia to manage problematic weeds. For HWSC to be effective, a high proportion of weed seeds must be retained on the plant at crop maturity. This 2-yr (2014, 2015) study evaluated seed shatter of wild oat, green foxtail, wild mustard, and cleavers in both an early (field pea) and late (spring wheat) maturity crop in field experiments at Scott, Saskatchewan. Seed shatter was assessed using shatter trays collected once a week during crop ripening stage, as well as at two crop maturation or harvest stages (swathing, direct-combining). Seed shatter differed among weed species, but was similar between crops at maturity: ca. 30% for wild oat, 5% for cleavers, < 2% for wild mustard, and < 1% for green foxtail. Overall, seed shatter of wild oat occurred sooner and at greater levels during the growing season compared with the other weed species. Viability of both shattered and plant-retained seeds was relatively high for all species. The small amount of seed shatter of cleavers, wild mustard, and green foxtail suggests that these species may be suitable candidates for HWSC. Due to the amount and timing of wild oat seed shatter, HWSC may not reduce population abundance of this grassy weed.

Comparison of weed communities in Manitoba ecoregions and crops

2000 ◽  
Vol 80 (4) ◽  
pp. 963-972 ◽  
Author(s):  
R. C. Van Acker ◽  
A. G. Thomas ◽  
J. Y. Leeson ◽  
S. Z. Knezevic ◽  
B. L. Frick
Keyword(s):  
Weed Management ◽  
Amaranthus Retroflexus ◽  
Weed Species ◽  
Canada Thistle ◽  
Wild Mustard ◽  
Polygonum Convolvulus ◽  
Weed Communities ◽  
Green Foxtail ◽  
Poaceae Family ◽  
Weed Survey

In 1997, a weed survey was conducted during July and August in fields of wheat, barley, oat, canola and flax in Manitoba. Field selection was based on a stratified-random sampling methodology using ecodistricts as strata. Species in the Poaceae family were most commonly observed in the survey, followed by species in the Polygonaceae, Asteraceae and Brassicaceae families. The six most abundant weed species were green foxtail [Setaria viridis (L.) Beauv.], wild oats (Avena fatua L.), wild buckwheat (Polygonum convolvulus L.), Canada thistle (Cirsium arvense L.), redroot pigweed (Amaranthus retroflexus L.) and wild mustard (Sinapis arvensis L.). The survey highlighted significant differences between ecoregions and between crops in residual weed infestations. The weed community in the Boreal Transition ecoregion was dominated by seven species, whereas fields in the Aspen Parkland and Lake Manitoba Plain ecoregions were dominated by two species and the Interlake Plain ecoregion was dominated by only one species. Although significant differences were found between the weed communities in crops, they were not as great as differences between ecoregions. The Manitoba residual weed community in 1997 was very similar to that reported for 1978–1981 and 1986, suggesting that the same species should remain a focus for weed management. Key words: Weed survey, weed relative abundance, weed distributions, Manitoba ecoregions

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.

Tolpyralate Efficacy: Part 1. Biologically Effective Dose of Tolpyralate for Control of Annual Grass and Broadleaf Weeds in Corn

2018 ◽  
Vol 32 (6) ◽  
pp. 698-706 ◽  
Author(s):  
Brendan A. Metzger ◽  
Nader Soltani ◽  
Alan J. Raeder ◽  
David C. Hooker ◽  
Darren E. Robinson ◽  
...  
Keyword(s):  
Effective Dose ◽  
Weed Management ◽  
Field Studies ◽  
Biologically Effective Dose ◽  
Limited Information ◽  
Weed Species ◽  
Common Lambsquarters ◽  
Wild Mustard ◽  
Low Field ◽  
Green Foxtail

AbstractTolpyralate is a new 4-hydroxyphenyl-pyruvate dioxygenase (HPPD)-inhibiting herbicide for POST weed management in corn; however, there is limited information regarding its efficacy. Six field studies were conducted in Ontario, Canada, over 3 yr (2015 to 2017) to determine the biologically effective dose of tolpyralate for the control of eight annual weed species. Tolpyralate was applied POST at six doses from 3.75 to 120 g ai ha−1and tank mixed at a 1:33.3 ratio with atrazine at six doses from 125 to 4,000 g ha−1. Regression analysis was performed to determine the effective dose (ED) of tolpyralate, and tolpyralate+atrazine, required to achieve 50%, 80%, or 90% control of eight weed species at 1, 2, 4, and 8 wk after application (WAA). The ED of tolpyralate for 90% control (ED90) of velvetleaf, common lambsquarters, common ragweed, redroot pigweed or Powell amaranth, and green foxtail at 8 WAA was ≤15.5 g ha−1; however, tolpyralate alone did not provide 90% control of wild mustard, barnyardgrass, or ladysthumb at 8 WAA at any dose evaluated in this study. In contrast, the ED90for all species in this study with tolpyralate+atrazine was ≤13.1+436 g ha−1, indicating that tolpyralate+atrazine can be highly efficacious at low field doses.

Influence of application timing and herbicide rate on the efficacy of tolpyralate plus atrazine

2019 ◽  
Vol 33 (03) ◽  
pp. 448-458 ◽  
Author(s):  
Brendan A. Metzger ◽  
Nader Soltani ◽  
Alan J. Raeder ◽  
David C. Hooker ◽  
Darren E. Robinson ◽  
...  
Keyword(s):  
Weed Management ◽  
Field Experiments ◽  
Integrated Weed Management ◽  
Herbicide Application ◽  
Weed Species ◽  
Common Ragweed ◽  
Application Timing ◽  
Common Lambsquarters ◽  
Green Foxtail ◽  
Equivalent Control

AbstractEffective POST herbicides and herbicide mixtures are key components of integrated weed management in corn; however, herbicides vary in their efficacy based on application timing. Six field experiments were conducted over 2 yr (2017–2018) in southwestern Ontario, Canada, to determine the effects of herbicide application timing and rate on the efficacy of tolpyralate, a new 4-hydroxyphenyl pyruvate dioxygenase inhibitor. Tolpyralate at 15, 30, or 40 g ai ha−1 in combination with atrazine at 500 or 1,000 g ai ha−1 was applied PRE, early POST, mid-POST, or late POST. Tolpyralate + atrazine at rates ≥30 + 1,000 g ha−1 provided equivalent control of common lambsquarters and Powell amaranth applied PRE or POST, whereas no rate applied PRE controlled common ragweed, velvetleaf, barnyardgrass, or green foxtail. Common ragweed, common lambsquarters, velvetleaf, and Powell amaranth were controlled equally regardless of POST timing. In contrast, control of barnyardgrass and green foxtail declined when herbicide application was delayed to the late-POST timing, irrespective of herbicide rate. Similarly, corn grain yield declined within each tolpyralate + atrazine rate when herbicide applications were delayed to late-POST timing. Overall, the results of this study indicate that several monocot and dicot weed species can be controlled with tolpyralate + atrazine with an early to mid-POST herbicide application timing, before weeds reach 30 cm in height, and Powell amaranth and common lambsquarters can also be controlled PRE. Additionally, this study provides further evidence highlighting the importance of effective, early-season weed control in corn.

Seed and microsite limitations to emergence of four annual weed species

Weed Science ◽  
2004 ◽  
Vol 52 (4) ◽  
pp. 571-577 ◽  
Author(s):  
Nathan Boyd ◽  
Rene Van Acker
Keyword(s):  
Soil Compaction ◽  
Management Practices ◽  
Seed Density ◽  
Wild Oat ◽  
Annual Species ◽  
Weed Species ◽  
Wild Mustard ◽  
Green Foxtail ◽  
Weed Emergence ◽  
Number Of Seeds

The emergence of annual species depends on the number of seeds present and the biotic and abiotic conditions directly surrounding those seeds (the microsite). A field experiment was conducted to study the relative importance of seed presence vs. microsite conditions in determining the emergence of four annual species. Green foxtail, wild mustard, wild oat, and canola were seeded at 200, 400, and 1,200 seeds m−2in separate plots in a coarse, loamy, mixed Typic Haplocryoll and a fine, mixed Typic Haplocryoll soil. Five microsite modification treatments (control, irrigation, soil compaction, soil compaction plus irrigation, and no crop) were applied to all weed seed density treatments for each weed species. All plots were seeded to spring wheat. Irrigation or soil compaction increased percent emergence of wild oat. Green foxtail emergence tended to increase with soil compaction in 2001 but not in 2002. Wild mustard and canola emergence were largely unaffected by microsite modification treatments. Weed emergence increased with increasing seed density for all species, but the proportion of the total number of seeds emerging decreased with increasing seed density for all species. We suggest that the emergence of the four weed species in this experiment was both seed and microsite limited. Increasing the number of seeds in the soil increased the probability of seeds landing within an appropriate microsite. For these four species, therefore, weed spread and weed patch formation may be determined both by seed production and dispersal and by variability in soil microsite conditions. Results suggest that weed management practices should limit seed dispersal of all species and discourage weed emergence of hard-to-control species during critical establishment periods.

Efficacy of trifluralin and halosulfuron for weed management in white bean

2020 ◽  
Vol 100 (2) ◽  
pp. 137-145
Author(s):  
Nader Soltani ◽  
Christy Shropshire ◽  
Peter H. Sikkema
Keyword(s):  
Seed Yield ◽  
Weed Management ◽  
Field Experiments ◽  
Bean Seed ◽  
Common Lambsquarters ◽  
Weed Interference ◽  
Wild Mustard ◽  
Green Foxtail ◽  
White Bean ◽  
Bean Yield

A total of six field experiments were conducted in southwestern Ontario over a 3-yr period (2016, 2017, 2018) to evaluate the efficacy of trifluralin and halosulfuron applied preplant incorporated (PPI) for weed management in white bean. Trifluralin, halosulfuron, and trifluralin + halosulfuron applied PPI caused as much as 2%, 6%, and 8% white bean injury, respectively. Weed interference delayed maturity and reduced white bean yield 56% compared with the weed-free control. Weed interference with trifluralin and halosulfuron applied alone reduced white bean seed yield as much as 35% and 29%, respectively; however, white bean seed yield with the trifluralin + halosulfuron tankmixes was similar to the weed-free control. Trifluralin, halosulfuron, and trifluralin + halosulfuron applied PPI provided 6%–12%, 75%–92%, and 71%–95% control of velvetleaf; 89%–95%, 93%–98%, and 96%–99% control of pigweed species; 5%–18%, 82%–96%, and 90%–97% control of common ragweed; 90%–97%, 81%–97%, and 95%–99% control of common lambsquarters; 23%–43%, 55%–88%, and 83%–96% control of flower-of-an-hour; 4%–25%, 94%–100%, and 95%–100% control of wild mustard; 96%–100%, 18%–45%, and 97%–100% control of barnyardgrass; and 92%–98%, 21%–40%, and 93%–98% control of green foxtail, respectively. Results indicated that low rates of trifluralin tank-mixed with halosulfuron has the potential to control problematic weeds and improve white bean yields in Ontario.

Herbicidal Potential of Catechol as an Allelochemical

2006 ◽  
Vol 61 (1-2) ◽  
pp. 69-73 ◽  
Author(s):  
Süleyman Topal ◽  
Ismail Kocaçalışkana ◽  
Orhan Arslan
Keyword(s):  
Phenolic Compounds ◽  
Weed Management ◽  
Potent Inhibitor ◽  
Management Strategies ◽  
The Other ◽  
Cirsium Arvense ◽  
Weed Species ◽  
Papaver Rhoeas ◽  
Triticum Vulgare ◽  
Wild Mustard

Abstract Catechol is an allelochemical which belongs to phenolic compounds synthesized in plants. Its herbicidal effects on weed species; field poppy (Papaver rhoeas), creeping thistle (Cirsium arvense), henbit (Lamium amplexicaule) and wild mustard (Sinapis arvensis) were investigated using wheat (Triticum vulgare) and barley (Hordeum vulgare) species as control plants. In comparison to 2,4-D (a common synthetic herbicide), 13.64 mᴍ of catechol have been found to have a strong herbicidal effect, as effective as 2,4-D on field poppy weed by killing it, and a suppressive herbicidal effect on the other weeds by inhibiting their growth significantly. Concerning all the weeds, in general, elongation of the shoot was affected more negatively than that of the root. Fresh weights of the weeds were decreased by catechol significantly only in field poppy but not in other weeds. The study reveals that catechol is a potent inhibitor of growth of the weeds and therefore it can be evaluated as a herbicide for future weed management strategies

Postemergence Control of Weeds in Winter Rapeseed,Brassica napus, by DPX-A7881

Weed Science ◽  
1990 ◽  
Vol 38 (4-5) ◽  
pp. 389-395 ◽  
Author(s):  
Finlay S. Buchanan ◽  
Clarence J. Swanton ◽  
Terry J. Gillespie
Keyword(s):  
Brassica Napus ◽  
Growth Stage ◽  
Field Experiments ◽  
Seed Quality ◽  
Herbicide Application ◽  
Weed Species ◽  
Common Lambsquarters ◽  
Wild Mustard ◽  
Green Foxtail ◽  
Winter Rapeseed

Field experiments were established to determine the dose and timing of DPX-A7881 applied postemergence for control of weeds in winter rapeseed. Wild mustard and shepherdspurse were effectively controlled by DPX-A7881. Control of these weeds by DPX-A7881 was dependent upon growth stage. The later the growth stage at time of herbicide application the poorer the control. Fall applications of DPX-A7881 provided greater control of wild mustard and shepherdspurse seedlings compared to spring applications. The 0.010 kg ai ha-1dose was as effective in controlling susceptible weed species as 0.030 kg ai ha-1. Control of common lambsquarters and redroot pigweed by DPX-A7881 was poor. Regardless of timing or amount of herbicide applied, DPX-A7881 did not significantly reduce dry weights of either barnyardgrass or green foxtail. Doses of DPX-A7881 ranging from 0.010 to 0.030 kg ai ha-1did not injure or adversely affect winter survival of rapeseed seedlings. Rapeseed yield and seed quality were not affected by DPX-A7881 applied postemergence.

scholarly journals Weed Management in White Bean With Pre-plant Incorporated Herbicides

2021 ◽  
Vol 13 (10) ◽  
pp. 1
Author(s):  
Nader Soltani ◽  
Christy Shropshire ◽  
Peter H. Sikkema
Keyword(s):  
Weed Control ◽  
Weed Management ◽  
Field Experiments ◽  
Design Factor ◽  
Common Ragweed ◽  
Common Lambsquarters ◽  
Wild Mustard ◽  
Green Foxtail ◽  
White Bean ◽  
Bean Yield

Five field experiments were conducted in Ontario Canada during 2018-2020 to determine the level of crop injury, weed control and white bean yield with up to four-way mixtures of herbicides applied preplant incorporated (PPI). The trials were arranged in a factorial design: Factor 1 was &ldquo;Grass herbicide&rdquo; including no grass herbicide, trifluralin, S-metolachlor and trifluralin + S-metolachlor and Factor 2 was &ldquo;Broadleaf herbicide&rdquo; including no broadleaf herbicide, halosulfuron, imazethapyr and halosulfuron + imazethapyr. At 2 and 4 weeks after emergence (WAE), there was minimal (&le; 4%) white bean injury. At 8 weeks after herbicide application (WAA), trifluralin, S-metolachlor or trifluralin + S-metolachlor averaged across Factor 2 controlled velvetleaf 69, 71 and 62%, respectively; halosulfuron, imazethapyr and halosulfuron + imazethapyr averaged across Factor 1 controlled velvetleaf 75, 95 and 97%, respectively. At 8 WAA, trifluralin, S-metolachlor and trifluralin + S-metolachlor controlled pigweed 93, 90 and 97%, respectively, and halosulfuron, imazethapyr and halosulfuron + imazethapyr controlled pigweed 97, 79 and 98%, respectively. At 8 WAA, trifluralin, S-metolachlor and trifluralin + S-metolachlor provided poor (&le; 32%) control of common ragweed while halosulfuron, imazethapyr and halosulfuron + imazethapyr controlled common ragweed 86, 53 and 87%, respectively. The 4-way tankmix of trifluralin, S-metolachlor, halosulfuron + imazethapyr controlled common ragweed 95%. At 8 WAA, trifluralin, S-metolachlor and trifluralin + S-metolachlor controlled common lambsquarters 81, 38 and 91%, respectively, and halosulfuron, imazethapyr and halosulfuron + imazethapyr controlled common lambsquarters 94, 97 and 99%, respectively. At 8 WAA, trifluralin, S-metolachlor and trifluralin + S-metolachlor provided poor (&le; 46%) control of wild mustard while halosulfuron, imazethapyr and halosulfuron + imazethapyr provided excellent (&ge; 97%) wild mustard control. At 8 WAA, trifluralin, S-metolachlor and trifluralin + S-metolachlor controlled barnyardgrass 70, 85 and 94%, respectively, and halosulfuron, imazethapyr and halosulfuron + imazethapyr controlled barnyardgrass 9, 50 and 59%, respectively. At 8 WAA, trifluralin, S-metolachlor and trifluralin + S-metolachlor controlled green foxtail 89 to 98% and halosulfuron, imazethapyr and halosulfuron + imazethapyr controlled green foxtail 19, 69 and 67%, respectively. Weed interference reduced white bean yield 76%. Generally, white bean yield reflected the level of weed control. Based on these results, the 2- and 3-way tankmixes of herbicides evaluated generally provide similar weed control as the 4-way tankmixes.

Brassicaceous Weed Seed Predation by Ground Beetles (Coleoptera: Carabidae)

Weed Science ◽  
2016 ◽  
Vol 64 (2) ◽  
pp. 294-302 ◽  
Author(s):  
Sharavari S. Kulkarni ◽  
Lloyd M. Dosdall ◽  
John R. Spence ◽  
Christian J. Willenborg
Keyword(s):  
Seed Predation ◽  
Weed Management ◽  
Physiological State ◽  
Seed Removal ◽  
Weed Seed ◽  
Weed Species ◽  
Wild Mustard ◽  
Activity Density ◽  
Field Pennycress ◽  
Species Activity

We used laboratory and field feeding trials to investigate adult carabid beetle preferences for three brassicaceous weed species (rapeseed, wild mustard, and field pennycress) that are pests in canola. All carabid species preferred seeds of rapeseed most and those of field pennycress least and showed intermediate preference for wild mustard seeds. Beetles highly preferred imbibed seeds of all three weed species. Activity–density of carabids and mean weed seed removal were highly correlated in field plots of canola, with activity–density accounting for 67% of the observed variation in seed removal. Our study indicates that seed consumption among carabids is influenced by several factors, including weed species, physiological state of seeds, and carabid activity–density. Carabid seed predation is significant in canola agroecosystems; therefore, understanding these influences has implications for ecological weed management.

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