Effect of Early Competition on Growth of Common Milkweed

Weed Science ◽  
1975 ◽  
Vol 23 (1) ◽  
pp. 1-3 ◽  
Author(s):  
L. L. Evetts ◽  
O. C. Burnside
Keyword(s):  
Sorghum Bicolor ◽  
Amaranthus Retroflexus ◽  
Setaria Viridis ◽  
Light Competition ◽  
Asclepias Syriaca ◽  
Redroot Pigweed ◽  
Light Soil ◽  
Green Foxtail ◽  
Shoot Weight ◽  
Annual Weeds

Four modes of competition were studied in relation to early development of common milkweed (Asclepias syriacaL.) alone and in competition with green foxtail [Setaria viridis(L.) Beauv], redroot pigweed (Amaranthus retroflexusL.), and sorghum [Sorghum bicolor(L.) Moench ‘RS-626’]. The three species were used to study the effect of no competition, light competition, soil competition, and light and soil (full) competition on common milkweed. Common milkweed height was significantly reduced by soil and full competition with the three species, while only green foxtail caused a significant reduction in height due to light competition. Shoot weight of common milkweed was significantly reduced by light, soil, and full competition by the three species. Reproduction percentage of common milkweed roots was most severely reduced by light and full competition from green foxtail and redroot pigweed. An environment conducive to the establishment of the perennial common milkweed from seed exists when annual weeds are removed by herbicides.

Germination of Exhumed Weed Seed in Nebraska

Weed Science ◽  
1981 ◽  
Vol 29 (5) ◽  
pp. 577-586 ◽  
Author(s):  
Orvin C. Burnside ◽  
Charles R. Fenster ◽  
Larry L. Evetts ◽  
Robert F. Mumm
Keyword(s):  
Amaranthus Retroflexus ◽  
Setaria Viridis ◽  
Weed Species ◽  
Kochia Scoparia ◽  
Asclepias Syriaca ◽  
Rapid Loss ◽  
Digitaria Sanguinalis ◽  
Redroot Pigweed ◽  
Green Foxtail ◽  
Panicum Dichotomiflorum

An experiment was initiated in 1970 and continued through 1979 by exhuming and germinating seed of 12 economic weed species buried beneath 23 cm of soil in eastern and western Nebraska. Loss in germination of exhumed seeds over years is mathematically characterized by the formula for the rectangular hyperbola, which represents many shapes of curves that have zero as their lower limit. Of the 12 weed species, only fall panicum (Panicum dichotomiflorumMichx.) and redroot pigweed (Amaranthus retroflexusL.) seed germination did not drop significantly over the 10-yr burial period. Germination of redroot pigweed seed was higher when buried in eastern Nebraska, but was higher for smooth groundcherry (Physalis subglabrataMack&Bush.) and velvetleaf (Abutilon theophrastiMedic.) when buried in western Nebraska. Germination of the other nine species were not affected by burial location. The 12 weed species can be ranked as those showing most to least rapid loss of germination during burial for 10 yr as follows: honeyvine milkweed [Ampelamus albidus(Nutt.) Britt.], hemp dogbane (Apocynum cannabinumL.), kochia [Kochia scoparia(L.) Schrad.], sunflower (Helianthus annumL.), large crabgrass [Digitaria sanguinalis(L.) Scop.], common milkweed (Asclepias syriacaL.), musk thistle (Carduus nutansL.), velvetleaf, fall panicum, redroot pigweed, green foxtail [Setaria viridis(L.) Beauv.], and smooth groundcherry.

The Fate of Nitrofen in Rape, Redroot Pigweed, and Green Foxtail

Weed Science ◽  
1971 ◽  
Vol 19 (5) ◽  
pp. 555-558 ◽  
Author(s):  
D. Hawton ◽  
E. H. Stobbe
Keyword(s):  
Light Intensity ◽  
Brassica Campestris ◽  
Molecular Size ◽  
Amaranthus Retroflexus ◽  
High Light ◽  
Setaria Viridis ◽  
Light Conditions ◽  
Ether Linkage ◽  
Redroot Pigweed ◽  
Green Foxtail

The fate of 2,4-dichlorophenyl p-nitrophenyl ether (nitrofen) in the foliage of rape (Brassica campestris L. ‘Echo’), redroot pigweed (Amaranthus retroflexus L.), and green foxtail (Setaria viridis (L.) Beauv.) was investigated with the aid of 14C-nitrofen. Only limited amounts of the label were translocated in these species. Plants treated with 14C-nitrofen under high light conditions produced several labelled compounds of different molecular size and chromatographic properties. The time at which these compounds were first detectable depended on light intensity. At least two of these compounds are lipid-nitrofen conjugates or nitrofen polymers and others may be formed by cleavage of nitrofen at the ether linkage.

Selectivity of Nitrofen among Rape, Redroot Pigweed, and Green Foxtail

Weed Science ◽  
1971 ◽  
Vol 19 (1) ◽  
pp. 42-44 ◽  
Author(s):  
D. Hawton ◽  
E. H. Stobbe
Keyword(s):  
Brassica Campestris ◽  
Amaranthus Retroflexus ◽  
Water Soluble ◽  
Setaria Viridis ◽  
Weed Species ◽  
Differential Effects ◽  
Redroot Pigweed ◽  
Green Foxtail

The selectivity of 2,4-dichlorophenylp-nitrophenyl ether (nitrofen) among rape (Brassica campestrisL., var. Echo) and two weed species, redroot pigweed (Amaranthus retroflexusL.) and green foxtail (Setaria viridis(L.) Beauv.), was determined quantitatively by a replicated dosage-response experiment. On an ED50basis, green foxtail and redroot pigweed were, respectively, 5.8 and 63.3 times more susceptible than rape. Selectivity was divided into three parameters; viz., differential spray retention, differential penetration, and differential effects within the plant. Differences in retention were measured with the use of a water-soluble dye, while differences in penetration were determined with14C-labelled nitrofen. Spray retention on green foxtail was 66% of that on the rape and 64% as much nitrofen penetrated redroot pigweed as penetrated rape. Under the conditions of these tests it was estimated that green foxtail and redroot pigweed were, respectively, 9 and 99 times more susceptible to nitrofen than was rape.

scholarly journals Differential susceptibility of agricultural weeds to ultraviolet-B radiation

2002 ◽  
Vol 82 (4) ◽  
pp. 789-796 ◽  
Author(s):  
N. H. Furness ◽  
M. K. Upadhyaya
Keyword(s):  
Leaf Area ◽  
Chenopodium Album ◽  
Amaranthus Retroflexus ◽  
Ultraviolet B ◽  
Setaria Viridis ◽  
Stellaria Media ◽  
Redroot Pigweed ◽  
Green Foxtail ◽  
Lamb’S Quarters ◽  
Polygonum Persicaria

Differential morphological sensitivity of weed species to ultraviolet-B (UV-B) radiation (290–320 nm) may alter competitive relationships among weeds and associated crop species as the level of this radiation changes. In order to determine relative sensitivity of common chickweed [Stellaria media (L.) Vill.], green foxtail (Setaria viridis L.), lady's-thumb (Polygonum persicaria L.), lamb's-quarters (Chenopodium album L.), redroot pigweed (Amaranthus retroflexus L.), and shepherd's-purse (Capsella bursa-pastoris L.) to this radiation, seedlings were grown under 0, 7, and 11 kJ m-2 d-1 of biologically effective UV-B radiation in a greenhouse for 6 wk. The influence of UV-B radiation on seedling growth and morphology was investigated. UV-B radiation reduced shoot height in green foxtail (by up to 41%), lamb's-quarters, and redroot pigweed, and increased tillering in green foxtail seedlings. Leaf area and leaf biomass in common chickweed, green foxtail, lamb's-quarters, and shepherd's-purse, and stalk biomass in common chickweed, green foxtail, lamb's-quarters, redroot pigweed and shepherd's-purse declined in response to UV-B radiation. In common chickweed, leaf area was reduced by 74% at 11 kJ m-2 d-1. Root biomass was reduced by UV-B radiation in all species (up to 68% at 11 kJ m-2 d-1 in common chickweed) except lady's-thumb. Specific leaf weight increased and leaf area ratio declined in response to UV-B radiation in common chickweed and shepherd's-purse. Exposure to UV-B radiation increased the leaf weight ratio in common chickweed. Shoot:root ratios increased in response to UV-B radiation in common chickweed and redroot pigweed. Scanning electron microscopy revealed collapsed epidermal cells in occasional necrotic regions on adaxial leaf surfaces of redroot pigweed grown under 11 kJ m-2 d-1 UV-B radiation. Morphology and growth of lady's-thumb were not affected by UV-B radiation. This study suggests that common agricultural weeds have differential morphological and growth responses to UV-B-enhanced environments. Sensitivity to UV-B radiation was greatest for common chickweed and least for lady's-thumb and redroot pigweed. Key words: ultraviolet-B, Amaranthus retroflexus, Capsella bursa-pastoris, Chenopodium album, Polygonum persicaria, Setaria viridis, Stellaria media

scholarly journals Potential new tool for weed control in organically grown agronomic crops

2007 ◽  
Vol 52 (2) ◽  
pp. 95-104 ◽  
Author(s):  
Stevan Knezevic ◽  
Santiago Ulloa
Keyword(s):  
Field Experiments ◽  
Logistic Models ◽  
Amaranthus Retroflexus ◽  
Sorghum Halepense ◽  
Setaria Viridis ◽  
Agronomic Crops ◽  
Green Foxtail ◽  
Baseline Information ◽  
Weed Tolerance ◽  
Organically Grown

Field experiments were conducted during summer 2007 to determine a baseline information on crop and weed tolerance to broadcast flaming utilizing different rates of propane. The species evaluated were: maize (Zea mays), sorghum (Sorghum halepense), soybean (Glycine max), sunflower (Helianthus annuus), barnyardgrass (Echinocloa crus-galli), green foxtail (Setaria viridis), velvetleaf (Abutilon theophrasti) and redroot pigweed (Amaranthus retroflexus). The propane rates applied were 0, 12.1, 30.9, 49.7, 68.5 and 87.22 kg/ha. The response of the plants to propane rates were described by log-logistic models. Plant response to flame varied depending on the species, growth stage and propane rate. Broadleaf weeds were more susceptible to flames than grasses. Field maize and sorghum were less susceptible, while soybean and sunflower were severely injured. Of all crops tested, broadcast flaming has the most potential for use in field maize.

Competition Between Annual Weeds and Sweet Spanish Onions

Weed Science ◽  
1973 ◽  
Vol 21 (5) ◽  
pp. 436-439 ◽  
Author(s):  
G. A. Wicks ◽  
D. N. Johnston ◽  
D. S. Nuland ◽  
E. J. Kinbacher
Keyword(s):  
Allium Cepa ◽  
Amaranthus Retroflexus ◽  
Kochia Scoparia ◽  
Redroot Pigweed ◽  
Annual Weeds

The competitiveness of annual weeds in irrigated sweet Spanish onions (Allium cepaL.) was studied at North Platte, Nebraska, during 1969 and 1970. Weeds allowed to grow in the row for 2, 4, 6, and 8 weeks after onion emergence reduced onion yields 20, 20, 40, and 65%, respectively. When plots were kept weed-free until onion emergence and 2, 4, 6, 8, 10, and 12 weeks after emergence, onion yields were reduced 100, 99, 87, 75, 46, 25, and 5%, respectively. Redroot pigweed (Amaranthus retroflexusL.), kochia (Kochia scopariaL.), and grass weeds accounted for 54, 21, and 21%, respectively, of the total weed yield.

Integrated weed management in white bean production

2008 ◽  
Vol 88 (3) ◽  
pp. 555-561 ◽  
Author(s):  
Peter H Sikkema ◽  
Richard J Vyn ◽  
Christy Shropshire ◽  
Nader Soltani
Keyword(s):  
Phaseolus Vulgaris ◽  
Weed Management ◽  
Amaranthus Retroflexus ◽  
Profit Margin ◽  
Phaseolus Vulgaris L ◽  
Navy Bean ◽  
Common Lambsquarters ◽  
Redroot Pigweed ◽  
Green Foxtail ◽  
White Bean

A study was conducted over a 3-yr period (2004–2006) in Ontario to evaluate various weed management programs in white bean (Phaseolus vulgaris L.). Herbicide treatments evaluated caused no visible injury in white bean. Trifluralin provided 12% (percentage points) greater control of common lambsquarters (Chenopodium album L.) than s-metolachlor. There was no benefit of tank-mixing s-metolachlor and trifluralin for yield and profitability compared with either trifluralin or s-metolachlor alone. The postemergence (POST ) application of bentazon plus fomesafen following a soil-applied herbicide resulted in improved control of common lambsquarters by 15%. Two inter-row cultivations following a soil-applied herbicide resulted in improved control of redroot pigweed (Amaranthus retroflexus L.), common lambsquarters, and green foxtail [Setaria viridis (L.) Beauv.]. The addition of imazethapyr (60% of label dose; 45 g a.i. ha-1) to the soil-applied herbicide resulted in improved control of redroot pigweed (+6%), common lambsquarters (+16%), and green foxtail (+6%). The profit margin tended to increase if more than just a grass preplant-incorporated (PPI) herbicide was used. The best profit margin was with a grass PPI herbicide alone plus cultivation. The profit margin also tended to increase with the use of cultivation rather than a broadleaf POST herbicide. Key words: Bentazon, cultivation, fomesafen, imazethapyr, navy bean, s-metolachlor, trifluralin, Phaseolus vulgaris L.

Interference of Redroot Pigweed (Amaranthus retroflexus) and Robust Foxtail (Setaria viridisvar.robusta-albaor var.robusta-purpurea) in Soybeans (Glycine max)

Weed Science ◽  
1979 ◽  
Vol 27 (6) ◽  
pp. 665-674 ◽  
Author(s):  
P. L. Orwick ◽  
M. M. Schreiber
Keyword(s):  
Glycine Max ◽  
Seed Yield ◽  
Initial Density ◽  
Soybean Seed ◽  
Amaranthus Retroflexus ◽  
Row Spacing ◽  
Setaria Viridis ◽  
Redroot Pigweed ◽  
Growing Seasons ◽  
Wide Row Spacing

Redroot pigweed (Amaranthus retroflexusL.) and robust foxtail [Setaria viridis(L.) Beauv. var.robusta-albaSchreiber (RWF) orSetaria viridisvar.robusta-purpureaSchreiber (RPF)] were investigated regarding their ability to interfere with soybean [Glycine max(L.) Merr. ‘Amsoy 71′] at different weed densities and soybean row spacing throughout two growing seasons. Final weed densities for each species tended to reach a common value because of intraspecific interference regardless of the initial density. With cultivation, a narrow soybean row spacing (38 cm) resulted in less weed growth than did a wide row spacing (76 cm) but with no cultivation, the trend was reversed. Soybeans provided less interference to foxtail than to pigweed during both growing seasons. Interference from foxtail adversely affected soybean yield components and soybean seed yield more than did pigweed interference. Water-stress conditions in 1976 increased the intensity of weed interference and reduced soybean seed yield more severely than in 1975 when moisture was adequate throughout the growing season.

Mechanical, Cultural, and Chemical Control of Weeds in a Sorghum-Soybean(Sorghum bicolor)–(Glycine max)Rotation

Weed Science ◽  
1978 ◽  
Vol 26 (4) ◽  
pp. 362-369 ◽  
Author(s):  
O. C. Burnside
Keyword(s):  
Glycine Max ◽  
Sorghum Bicolor ◽  
Weed Control ◽  
Crop Rotation ◽  
Weed Competition ◽  
Setaria Viridis ◽  
Digitaria Sanguinalis ◽  
Weed Growth ◽  
Green Foxtail ◽  
Polygonum Pensylvanicum

A crop rotation of sorghum [Sorghum bicolor(L.) Moench] and soybeans [Glycine max(L.) Merr.] with various weed control treatments was conducted from 1968 to 1975 at Lincoln, Nebraska, in order to improve weed control in these two crops. Poor weed control during one growing season increased weed growth and decreased yields of succeeding crops. Trifluralin (α,α,α-trifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine) at 1.1 kg/ha on soybeans showed greater soil carryover toxicity to sorghum planted 12 months later than did atrazine [2-chloro-4-(ethylamino)-6-(isopropylamino)-s-triazine] at 3.4 kg/ha on sorghum to subsequently planted soybeans. Under this crop rotation green foxtail [Setaria viridis(L.) Beauv.], tall waterhemp [Amaranthus tuberculatos(Moq.) J. Sauer], and large crabgrass [Digitaria sanguinalis(L.) Scop.] decreased; whereas, velvetleaf(Abutilon theophrastiMedic), sunflower(Helianthus annuusL.), and Pennsylvania smartweed(Polygonum pensylvanicumL.) increased. Germinating weed seedlings from soil samples were greater in weedy check plots during the final years of the crop rotation due to a buildup of seed from those species that increased. Handweeding, herbicides, and plowing reduced weed populations, weed competition, and increased sorghum and soybean yields.

Effect of Additives upon Phenmedipham for Weed Control in Sugarbeets

Weed Science ◽  
1973 ◽  
Vol 21 (1) ◽  
pp. 67-70 ◽  
Author(s):  
Stephen D. Miller ◽  
John D. Nalewaja
Keyword(s):  
Weed Control ◽  
Linseed Oil ◽  
Chenopodium Album ◽  
Amaranthus Retroflexus ◽  
Herbicidal Activity ◽  
Redroot Pigweed ◽  
Wild Mustard ◽  
Green Foxtail ◽  
Helianthus Annus ◽  
Brassica Kaber

Weed control and sugarbeet (Beta vulgarisL.) injury from applications of methylm-hydroxycarbanilatem-methyl-carbanilate (phenmedipham) were influenced by additives, volume of additive, and species in both field and greenhouse experiments. Oils were more effective than the surfactant as additives to phenmedipham on green foxtail (Setaria virdis(L.) Beauv.), yellow foxtail (Setaria glauca(L.) Beauv.), redroot pigweed (Amaranthus retroflexusL.), or common lambsquarters (Chenopodium albumL.). Herbicidal activity of phenmedipham on kochia (Kochia scoparia(L.) Schrad.) or wild mustard (Brassica kaber(D.C.) L.C. Wheeler var.pinnatifida(Stokes) L.C. Wheeler) was not enhanced by any additive. Linseed oil (2.34 L/ha) enhanced the herbicidal activity of phenmedipham on green foxtail, yellow foxtail, and redroot pigweed more than petroleum (2.34 L/ha) or sunflower (Helianthus annusL.) oil (2.34 or 9.35 L/ha). However, linseed oil reduced the herbicidal activity of phenmedipham on kochia.

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