Velvetleaf (Abutilon theophrasti Medik.) productivity in competitive conditions

Velvetleaf (Abutilon theophrasti Medik.) is an invasive alien species in many countries and one of the major weeds in summer row crops worldwide. Weed-management techniques that reduce weed production need to be investigated to provide new approaches. The first step in this process is the determination of weed productivity in different competitive conditions. Field experiments were conducted in 2006 and 2008 in an experimental field in Padinska Skela to quantify growth and seed production of velvetleaf in maize, as well as in a velvetleaf monoculture. A density of velvetleaf ranging from 1 to 8 plants m-1 was artificially created. In a mixture with maize, velvetleaf was sown in crop rows. The growth of velvetleaf was estimated based on plant height, fresh aboveground biomass and leaf area index (LAI). Velvetleaf fecundity was determined as seed mass plant-1 and seed mass m-2. Differences between years in plant production were very prominent. In general, velvetleaf productivity in maize depended on its density. Intraspecific competition had a major influence on growth and seed production when velvetleaf density was from 4 to 8 plants m-1 in maize rows. This information indicates that environmental conditions and weed density can promote/reduce inter- and intraspecific competition and help in the construction of population dynamics models to predict population density, seed bank and competitiveness of weeds and reduce inputs for weed management.

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Influence of barnyardgrass (Echinochloa crus-galli) time of emergence and density on corn (Zea mays)

Weed Science ◽

10.1017/s0043174500092833 ◽

1997 ◽

Vol 45 (2) ◽

pp. 276-282 ◽

Cited By ~ 91

Author(s):

Aca C. Bosnic ◽

Clarence J. Swanton

Keyword(s):

Leaf Area ◽

Seed Production ◽

Weed Management ◽

Field Experiments ◽

Yield Loss ◽

Seedling Emergence ◽

Integrated Weed Management ◽

Corn Yield ◽

Area Index ◽

Leaf Stage

Barnyardgrass is a serious weed problem in cornfields in Ontario. Field experiments were conducted at two locations in 1994 and 1995 to determine the influence of emergence time and barnyardgrass density on corn yield loss, leaf area at 50% silking, and barnyardgrass seed production. Selected barnyardgrass densities up to 200 plants m−1were established within 12.5 cm on either side of the corn row. Barnyardgrass seeds were planted concurrently with corn and at the 3- to 5- or 1- to 2-leaf stage of corn growth in 1994 and 1995, respectively. Barnyardgrass density and seedling emergence relative to corn influenced the magnitude of corn yield loss. Maximum corn grain yield loss ranged from 26 to 35% for early emerging barnyardgrass, and less than 6% yield loss occurred from barnyardgrass seedlings emerging later than the 4-leaf stage of corn growth. Changes in corn leaf area index at 50% silking reflected the level of barnyardgrass competition in corn. Maximum leaf area reduction ranged from 21 to 23%. Barnyardgrass seed production varied with time of seedling emergence and density. Ten barnyardgrass plants emerging up to the 3-leaf stage of corn growth produced 14,400 to 34,600 seeds m−2compared to only 1,200 to 2,800 seeds m−2from plants emerging after the 4-leaf corn stage. The results of this study are essential in the development of an integrated weed management strategy for corn.

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Competition betweenElymus elymoidesandTaeniatherum caput-medusae

Weed Science ◽

10.1017/s0043174500091396 ◽

1999 ◽

Vol 47 (6) ◽

pp. 720-728 ◽

Cited By ~ 27

Author(s):

David W. Clausnitzer ◽

Michael M. Borman ◽

Douglas E. Johnson

Keyword(s):

Soil Moisture ◽

Interspecific Competition ◽

Seed Production ◽

Intraspecific Competition ◽

Field Experiments ◽

Block Design ◽

Low Oxygen ◽

Competitive Effects ◽

Growing Seasons ◽

Randomized Block Design

Two field experiments were conducted from 1993–1994 through 1995–1996 growing seasons in Harney County, OR, to determine the relative competitive abilities ofElymus elymoides(squirreltail) a native perennial range grass, andTaeniatherum caput-medusae(medusahead), an exotic annual grass weed. The 1993–1994 growing season was very dry, 1994–1995 was dry, and 1995–1996 was wetter than average. One experiment tested seedlings vs. seedlings in each of three seasons. The second experiment tested seedlings plus second- and third-year establishedE. elymoidesplants vs. 77caput-medusaeover 2 yr. Biomass, seed production, and soil moisture utilization 15, 30, 45, and 60 cm deep by the two species were measured. A randomized block design with factorial arrangement was used, with 25 2.25-m2plots per block. Initial seeding densities of each species were 0, 10, 74, 550, and 4,074 seeds m−2in all combinations of density. In the seedling vs. seedling experiment, intraspecific competition by 77caput-medusaeon itself was always significant (P ≤ 0.10) for both biomass and seed production. Interspecific competition byE. elymoidesseedlings onT. caput-medusaebiomass and seed production was not significant (P ≥ 0.10) in 2 of 3 yr and was always less than intraspecific competition by 77caput-medusae. Only 0.4% ofE. elymoidesseed germinated, and no seed was produced in the very dry first year, but 84% of remaining seed was viable for the next year, which had better moisture conditions for germination and establishment. Interspecific competition affected (P ≤ 0.10)E. elymoidesseedling biomass and seed production throughout the study. Intraspecific competition affected (P ≤ 0.10) seedlingE. elymoidesseed production in the dry year but not in the wetter than average year. In the matureE. elymoidesexperiment, intraspecific competition byT. caput-medusaeon weight and seed production per plant was greater than interspecific competition fromE. elymoides. Seedling/matureE. elymoidesreducedT. caput-medusaeweight per plant in the dry year but the effect was not biologically significant. Larger, matureEelymoidesplants produced 600 to 3,000 seeds per plant during the wet year; neither intra- nor interspecific competition was a factor.Taeniatherum caput-medusaewas better able to access deeper soil moisture and was more aggressive at extracting soil moisture than wereE. elymoidesseedlings in the wet year. Cold soils and low oxygen due to wet soils may have restrictedE. elymoidesseedling root activity. MatureE. elymoidesplants did not appear restricted by cold soils or low oxygen. Established second- and third-yearE. elymoidesplants were able to compete for soil moisture down to 45 cm. The generally greater interspecific competitive effects ofT. caput-medusaeonE. elymoidesthan vice versa suggested that it will be difficult to establish anE. elymoidesstand in an existingT. caput-medusaecommunity without first suppressingT. caput-medusae. IndividualE. elymoidesplants did establish and were productive with and withoutT. caput-medusaecompetition.

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

Australian Journal of Experimental Agriculture ◽

10.1071/ea01002 ◽

2001 ◽

Vol 41 (8) ◽

pp. 1179 ◽

Cited By ~ 9

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.

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Effects ofEriochloa villosadensity and time of emergence on growth and seed production inZea mays

Weed Science ◽

10.1017/s0043174500091347 ◽

1999 ◽

Vol 47 (6) ◽

pp. 687-692 ◽

Cited By ~ 10

Author(s):

James A. Mickelson ◽

R. Gordon Harvey

Keyword(s):

Seed Production ◽

Field Experiments ◽

Seed Mass ◽

Model Parameters ◽

Growth Stages ◽

Vegetative Biomass ◽

Eriochloa Villosa ◽

Term Management ◽

Weed Emergence

Field experiments were conducted in 1997 and in 1998 to determine the effects of density and time of emergence onEriochloa villosagrowth and seed production inZea mays. E. villosawas transplanted at four densities (3, 9, 27, and 81 plants m−2) to simulate emergence at four Z.maysgrowth stages (VE, V2, V5, and V10). Compared toE. villosaplants that emerged withZ. maysplants, total above-groundE. villosabiomass at maturity of plants grown at 3 plants m−2was reduced by 54, 97, and 99% when emergence was delayed until the V2, V5, and V10 stages ofZ. mays, respectively, in 1997. In 1998, total abovegroundE. villosabiomass at maturity was reduced by 70, 87, and 99% when emergence was delayed until the V2, V5, and V10 stages ofZ. mays, respectively.E. villosaaboveground vegetative biomass per plant at maturity was linearly related to seed production per plant in each year.E. villosaseed production m−2decreased nonlinearly as density decreased and time of emergence was delayed. Based on estimated model parameters, maximum seed production was 57,100 and 12,700 seeds m−2in 1997 and 1998, respectively. Within time of emergence,E. villosadensity did not affect seed mass per seed, however, seed mass of late-emerging cohorts was less than that of early-emerging cohorts. Time of weed emergence relative to the crop was a very important factor in determining biomass and seed production. Results suggest that late-emerging plants may not be very important to long-term management ofE. villosa.

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

Weed Technology ◽

10.1017/wet.2019.61 ◽

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.

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Effect of Different Spacing and Weed Management Practices on Weeds, Crop Growth and Productivity of Pigeon Pea Variety Pusa Arhar-16

Indian Journal of Agricultural Research ◽

10.18805/ijare.a-5753 ◽

2021 ◽

Author(s):

Yadwinder Singh ◽

Kanwaljit Singh

Keyword(s):

Weed Management ◽

Management Practices ◽

Field Experiments ◽

Growth Parameters ◽

Growth Parameter ◽

Pigeon Pea ◽

Crop Growth ◽

Growth And Yield ◽

Area Index ◽

Yield Attributes

Background: To study effect of various spacing and weed management practices on weed control, growth parameter, yield and yield attributes of pigeon pea variety Pusa Arhar-16, field experiments were conducted at Student’s Research Farm, Khalsa College Amritsar, Punjab, India during kharif season of 2019-20.Methods: The experiment was laid out in Split plot design with three replications. The treatments comprised of four different spacing i.e. S1 (30×10 cm), S2 (30×15 cm), S3 (40×15 cm) and S4 (50×25 cm) which were considered as main plot treatments and three weed management practices W1 (weedy check), W2 (pendimethalin @ 1.5 kg a.i. ha-1 at 1DAS) and W3 (rice straw mulch) as sub-plot treatments.Result: It was found that maximum plant height (218.2 cm) and highest leaf area index (2.104) was recorded in treatment S1 (30×10 cm) whereas treatment S4 (50×25 cm) was superior in rest of growth parameters viz. maximum crop growth rate (0.85 gram per plant per day), number of primary branches (18.2 per plant) and number of secondary branches (13.8 per plant). Among yield and yield attributes, spacing S1 (30×10 cm) showed maximum grain yield (16.29 q ha-1) and stover yield (49.29 q ha-1) whereas, maximum number of pods per plant (154.6), pod length (4.83 cm), number of seeds per pod (3.90) and 100-seed weight (7.14 grams) were recorded in spacing S4 (50×25 cm). The weed management treatments showed non-significant effect on growth and yield parameters due to weed suppressing ability of the crop. which might be due to weed suppressing ability of the crop. It may be concluded that pigeon pea cultivar Pusa Arhar-16 performed better in narrower spacing of 30×10 cm due to its dwarf nature and it also showed good smothering effect on the weeds due to its smothering effect.

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Influence of Adjuvants on Efficacy of Imazapic and 2,4-DB

Peanut Science ◽

10.3146/i0095-3679-26-1-1 ◽

1999 ◽

Vol 26 (1) ◽

pp. 1-4 ◽

Cited By ~ 1

Author(s):

D. L. Jordan

Keyword(s):

Weed Management ◽

Field Experiments ◽

Amaranthus Retroflexus ◽

Major Influence ◽

Xanthium Strumarium ◽

Redroot Pigweed ◽

Eclipta Prostrata ◽

Pitted Morningglory ◽

Postemergence Herbicides ◽

Organosilicone Surfactant

Abstract Adjuvants can have a major influence on efficacy of postemergence herbicides. Imazapic and 2,4-DB are applied postemergence in peanut (Arachis hypogaea L.) to control a variety of weeds. Determining how adjuvants influence efficacy of these herbicides could lead to more efficient weed management. Field experiments were conducted during 1997 and 1998 to determine the influence of nonionic surfactant, crop oil concentrate, organosilicone surfactant, and a blend of organosilicone surfactant and methylated seed oil on efficacy of imazapic and 2,4-DB. No-adjuvant and nontreated controls were also included. Adjuvants did not increase redroot pigweed (Amaranthus retroflexus L.) or common cocklebur (Xanthium strumarium L.) control by imazapic. Only minor differences in control of eclipta (Eclipta prostrata L.), entireleaf morningglory (Ipomoea hederacea var. integriuscula Gray), and pitted morningglory (Ipomoea lacunosa L.) by imazapic were noted among adjuvants. Sicklepod [Senna obtusifolia (L.) Erwin and Barneby] and pitted morningglory control increased when 2,4-DB was applied with adjuvants. Common cocklebur control was improved in one of three experiments when adjuvants were applied with 2,4-DB. Redroot pigweed and entireleaf morningglory control by 2,4-DB was not affected by adjuvants.

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Growth Analysis of Soybeans (Glycine max) in Competition with Velvetleaf (Abutilon theophrasti)

Weed Science ◽

10.1017/s0043174500061622 ◽

1980 ◽

Vol 28 (6) ◽

pp. 729-734 ◽

Cited By ~ 66

Author(s):

E. S. Hagood ◽

T. T. Bauman ◽

J. L. Williams ◽

M. M. Schreiber

Keyword(s):

Glycine Max ◽

Field Experiments ◽

Dry Weight ◽

Abutilon Theophrasti ◽

Growth And Yield ◽

Planting Dates ◽

Area Index ◽

High Soil Moisture ◽

Soybean Plants ◽

Soybean Leaves

Field experiments were conducted to study the effects of varying velvetleaf (Abutilon theophrastiMedic.) densities and planting dates on the growth and yield of soybeans [Glycine max(L.) Merr. ‘Amsoy 71’]. Velvetleaf densities ranging from 2.5 to 40 plants/m2caused reductions in the dry weight of soybean leaves, stems, roots, and pods and seeds, and in the leaf area index, pod number, and seed yield when velvetleaf and soybean plants emerged at the same time. The magnitude of reduction in soybean growth and the time at which the reduction was first observed was dependent on weed density. Soybean growth reductions caused by high velvetleaf densities were less when conditions of high soil moisture content minimized the effects of competition for water. Velvetleaf emerging 21 and 23 days after soybean emergence did not reduce crop growth or yield.

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Velvetleaf (Abutilon theophrasti) Response to Glyphosate on the Field Edge

Weed Science ◽

10.1614/ws-07-173.1 ◽

2008 ◽

Vol 56 (3) ◽

pp. 464-468 ◽

Cited By ~ 1

Author(s):

Robert E. Nurse ◽

Kerry E. Bosveld ◽

Susan E. Weaver

Keyword(s):

Seed Production ◽

Weed Management ◽

Growth Stage ◽

Abutilon Theophrasti ◽

Herbicide Application ◽

Response Curves ◽

Application Rates ◽

Field Edge ◽

Soybean Canopy ◽

Crop Growth Stage

Control of weeds growing around field edges to limit seed production is an important component of preventative weed management. POST herbicide rates that are effective on weeds growing within a dense corn or soybean canopy may not be high enough to control weeds at the edge of a field. A study was conducted from 2004 through 2006 to compare velvetleaf growth and fecundity at the edge of the field as opposed to within the crop in response to a range of glyphosate rates. Treatments included position (plot center or edge), time of emergence (VE or V4 crop growth stage) and glyphosate rate (0 to 900 g ae ha−1). Without herbicide application, velvetleaf plants grown on the edge flowered earlier, had thicker stems, and produced more seed capsules than plants grown in the center of the plots. At glyphosate application rates of 200 to 900 g ha−1, the percentage of plants surviving and reproducing was higher on the edge than within the crop. Edge plants treated with 900 g ha−1of glyphosate produced more seeds than center plants that received no herbicide. Dose–response curves were used to estimate the glyphosate rate that would reduce seed production of surviving plants to 80% of the untreated plants. Plants emerging at the VE stage were estimated to require 300 g ha−1within the corn or soybean canopy and 668 g ha−1on the crop edge, whereas plants emerging at the V4 stage would require 0 g ha−1within the canopy and 280 g ha−1on the crop edge.

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