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

1999 ◽  
Vol 26 (1) ◽  
pp. 1-4 ◽  
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.

Effect of Corn-Induced Shading and Temperature on Rate of Leaf Appearance in Redroot Pigweed (Amaranthus retroflexus L.)

Weed Science ◽  
1993 ◽  
Vol 41 (4) ◽  
pp. 590-593 ◽  
Author(s):  
Stephane M. Mclachlan ◽  
Clarence J. Swanton ◽  
Stephan F. Weise ◽  
Matthijs Tollenaar
Keyword(s):  
Field Experiments ◽  
Linear Increase ◽  
Amaranthus Retroflexus ◽  
Planting Date ◽  
Weed Interference ◽  
Redroot Pigweed ◽  
Field Temperature ◽  
Effects Of Temperature ◽  
Leaf Appearance ◽  
Rate Of Leaf Appearance

Leaf development and expansion are important factors in determining the outcome of crop-weed interference. The comparative effects of temperature and corn canopy-induced shading on the rate of leaf appearance (RLA) of redroot pigweed were quantified in this study. Growth cabinet results indicated a linear increase in RLA with increased temperature. Weed RLA was predicted utilizing both this function and field temperature data. The ratio of observed to predicted RLA of redroot pigweed grown in field experiments decreased in 1990 and 1991 as shading increased with increased corn density and delayed weed planting date. Results indicated that RLA is substantially affected by canopy-induced shading in addition to temperature.

Interference of Redroot Pigweed (Amaranthus retroflexus) in Corn (Zea mays)

Weed Science ◽  
1994 ◽  
Vol 42 (4) ◽  
pp. 568-573 ◽  
Author(s):  
Stevan Z. Knezevic ◽  
Stephan F. Weise ◽  
Clarence J. Swanton
Keyword(s):  
Zea Mays ◽  
Grain Yield ◽  
Seed Production ◽  
Field Experiments ◽  
Amaranthus Retroflexus ◽  
Corn Yield ◽  
Leaf Stage ◽  
Redroot Pigweed ◽  
Emergence Date

Redroot pigweed is a major weed in corn throughout Ontario. Field experiments were conducted at two locations in 1991 and 1992 to determine the influence of selected densities and emergence times of redroot pigweed on corn growth and grain yield. Redroot pigweed densities of 0.5, 1, 2, 4 and 8 plants per m of row were established within 12.5 cm on either side of the corn row. In both years, redroot pigweed seeds were planted concurrently and with corn at the 3- to 5-leaf stage of corn growth. A density of 0.5 redroot pigweed per m of row from the first (earlier) emergence date of pigweed (in most cases, up to the 4-leaf stage of corn) or four redroot pigweed per m of row from the second (later) emergence date of pigweed (in most cases, between the 4- and 7-leaf stage of corn) reduced corn yield by 5%. Redroot pigweed emerging after the 7-leaf stage of corn growth did not reduce yield. Redroot pigweed seed production was dependent upon its density and time of emergence. The time of redroot pigweed emergence, relative to corn, may be more important than its density in assessing the need for postemergence control.

scholarly journals African star grass response to postemergence herbicides

2019 ◽  
Vol 43 ◽  
Author(s):  
Alexandre Magno Brighenti ◽  
Flávio Rodrigo Gandolfi Benites ◽  
Fausto Souza Sobrinho
Keyword(s):  
Nonionic Surfactant ◽  
Weed Management ◽  
Dry Matter ◽  
Field Experiments ◽  
Crop Management ◽  
Mineral Oil ◽  
Dry Matter Yield ◽  
Herbicide Application ◽  
Cynodon Nlemfuensis ◽  
Postemergence Herbicides

ABSTRACT Cynodon nlemfuensis Vanderyst, commonly called African star grass, is excellent forage in pasture formation and herd feeding. However, little information is available regarding weed management in areas of star grasses. Two field experiments were carried out in 2017 and 2018 to evaluate the response of African star grass to postemergence herbicides. The treatments applied were as follows: 2,4-D (1,340.0 g ae ha-1); 2,4-D + picloram (720.0 +192.0 g ae ha-1 + 0.3% v/v nonionic surfactant); fluroxypyr + picloram (80.0 + 80.0 g ae ha-1 + 0.3% v/v mineral oil); fluroxypyr + aminopyralid (160.0 + 80.0 g ae ha-1 + 0.3% v/v mineral oil); fluroxypyr + triclopyr (320.0 + 960.0 g ae ha-1 + 0.3% v/v mineral oil); bentazon (720.0 g ai ha-1 + 0.5% v/v mineral oil); imazapyr (25.0 g ai ha-1); monosodium methyl arsenate (MSMA) (1,440.0 g ai ha-1 + 0.1% v/v nonionic surfactant); atrazine + S-metolachlor (1,480.0 + 1,160.0 g ai ha-1); atrazine + tembotrione (1,000.0 + 100.8 g ai ha-1 + 0.3% v/v mineral oil) and a control without herbicide application. The most phytotoxic treatments for the African star grass plants were fluroxypyr + amininopyralid, fluroxypyr + triclopyr and atrazine + tembotrione. The dry matter yield of star grass plants was not reduced by the applications of 2,4-D, 2,4-D + picloram, bentazon, imazapyr, MSMA and atrazine + S-metolachlor. These herbicides can be considered potential practices in African star grass crop management.

scholarly journals Interaction of Insects and Weeds in a Snap Bean Agroecosystem

HortScience ◽  
2004 ◽  
Vol 39 (2) ◽  
pp. 287-290 ◽  
Author(s):  
Joseph N. Aguyoh ◽  
John B. Masiunas ◽  
Catherine Eastman
Keyword(s):  
Weed Management ◽  
Leaf Beetle ◽  
Amaranthus Retroflexus ◽  
Integrated Weed Management ◽  
Trifoliate Leaf ◽  
Snap Bean ◽  
Redroot Pigweed ◽  
Snap Beans ◽  
Bean Leaf Beetle ◽  
Large Crabgrass

Integrated weed management strategies maintain sub-threshold levels of weeds. The remaining weeds may impact the feeding and habitation patterns of both potato leafhoppers and bean leaf beetles in a snap bean agroecosystem. The objective of our study was to determine the effect of interference between snap beans (Phaseolus vulgaris L.) and either redroot pigweed (Amaranthus retroflexus L.) or large crabgrass (Digitaria sanguinalis L.) on populations of potato leafhopper [Empoasca fabae (Harris)] and bean leaf beetle [Cerotoma trifurcata (Forster)]. Plots were seeded with redroot pigweed or large crabgrass at either the same time as snap bean planting (early) or when snap bean had one trifoliate leaf open (late). The weed density averaged two plants per meter of row. Bean leaf beetle populations, snap bean pod damage, and leaf defoliation were lower in weed-free plots compared to those with either early emerging pigweed or crabgrass. Leafhopper nymphs and adults were 31% to 34% less in plots with crabgrass emerging with snap beans compared to those in weed-free snap bean plots. Thus, the effect of sub-threshold densities of pigweed and crabgrass on insect pests in snap bean varied depending on the species and should be considered when deciding to integrate weed management approaches.

Effect of Oil Adjuvants and Nitrogen Fertilizer on the Efficacy of Imazethapyr Applied at Conventional and Ultralow Spray Volumes

1998 ◽  
Vol 12 (3) ◽  
pp. 441-445 ◽  
Author(s):  
Gene D. Wills ◽  
James E. Hanks ◽  
Elizabeth J. Jones ◽  
Robert E. Mack
Keyword(s):  
Ammonium Nitrate ◽  
Nitrogen Fertilizer ◽  
Seed Oil ◽  
Field Experiments ◽  
Phosphate Esters ◽  
Pitted Morningglory ◽  
Spray Volume ◽  
Organosilicone Surfactant

Field experiments evaluated pitted morningglory, velvetleaf, and barnyardgrass control in soybean with imazethapyr applied alone and with either crop oil concentrate at 1.0% v/v, a blend of methylated seed oil and organosilicone surfactant, or a blend of methylated seed oil, phosphate esters, and organosilicone surfactant at 0.5% v/v, each with and without a 28% N mixture of urea and ammonium nitrate (URAN) applied at 2.3 L/ha. Treatments were applied at spray volumes of 94 and 9.4 L/ha. Control of each species was often increased with the addition of both oil adjuvants and URAN. The blend of methylated seed oil, phosphate esters, and organosilicone surfactant and the blend of methylated seed oil and organosilicone surfactant were each more effective than crop oil concentrate on pitted morningglory and barnyardgrass, while each oil adjuvant was similar on velvetleaf. The URAN effectively increased imazethapyr control of all species. Control of all species was similar at the spray volume of 9.4 L/ha and at 94 L/ha.

Influence of Time of Planting and Distance from the Cotton (Gossypium hirsutum) Row of Pitted Morningglory (Ipomoea lacunosa), Prickly Sida (Sida spinosa), and Redroot Pigweed (Amaranthus retroflexus) on Competitiveness with Cotton

Weed Science ◽  
1980 ◽  
Vol 28 (5) ◽  
pp. 568-572 ◽  
Author(s):  
G. A. Buchanan ◽  
J. E. Street ◽  
R. H. Crowley
Keyword(s):  
Gossypium Hirsutum ◽  
Amaranthus Retroflexus ◽  
Fresh Weight ◽  
Weed Species ◽  
Ipomoea Lacunosa ◽  
Redroot Pigweed ◽  
Weed Growth ◽  
Pitted Morningglory ◽  
Sida Spinosa ◽  
Prickly Sida

Influence of time of planting and distance from the cotton row of pitted morningglory (Ipomoea lacunosaL.), prickly sida (Sida spinosaL.), and redroot pigweed (Amaranthus retroflexusL.) on yield of seed cotton (Gossypium hirsutumL. ‘Stoneville 213’) was determined on Decatur clay loam during 1975 through 1978. Weed growth was measured in 1977 and 1978. Seeds of the three weed species were planted 15, 30, or 45 cm from the cotton row at time of planting cotton or 4 weeks later. Weeds planted 4 weeks after planting cotton grew significantly less than did weeds planted at the same time as cotton. When planted with cotton, redroot pigweed produced over twice as much fresh weight as did prickly sida or pitted morningglory. The distance that weeds were planted from the cotton row did not affect weed growth in 1978, but did in 1977. The distance that weeds were planted from the cotton row did not affect their competitiveness in any year as measured by yield of cotton. However, in each year, yields of cotton were reduced to a greater extent by weeds planted with cotton than when planted 4 weeks later. In 3 of 4 yr, there were significant differences in competitiveness of each of the three weed species with cotton.

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.

Influence of Application Variables on Efficacy of Glyphosate

1997 ◽  
Vol 11 (2) ◽  
pp. 354-362 ◽  
Author(s):  
David L. Jordan ◽  
Alan C. York ◽  
James L. Griffin ◽  
Patrick A. Clay ◽  
P. Roy Vidrine ◽  
...  
Keyword(s):  
Ammonium Sulfate ◽  
Weed Control ◽  
Field Experiments ◽  
Redroot Pigweed ◽  
Weed Growth ◽  
Pitted Morningglory ◽  
Three Stages ◽  
Hemp Sesbania ◽  
Prickly Sida ◽  
Potential Interactions

Field experiments were conducted from 1993 to 1995 to compare weed control by the isopropylamine salt of glyphosate at 0.21, 0.42, 0.63, and 0.84 kg ae/ha applied at three stages of weed growth. Weed control by glyphosate applied at these rates alone or with ammonium sulfate at 2.8 kg/ha was also evaluated. In other experiments, potential interactions between glyphosate and acifluorfen, chlorimuron, and 2,4-DB were evaluated. Velvetleaf, prickly sida, sicklepod, pitted morningglory, entireleaf morningglory, palmleaf morningglory, and hemp sesbania were controlled more easily when weeds had one to three leaves compared with control when weeds had four or more leaves. Glyphosate controlled redroot pigweed, velvetleaf, prickly sida, sicklepod, and barnyardgrass more effectively than pitted morningglory, entireleaf morningglory, palmleaf morningglory, or hemp sesbania. Increasing the rate of glyphosate increased control, especially when glyphosate was applied to larger weeds. Greater variation in control was noted for pitted morningglory, palmleaf morningglory, prickly sida, and velvetleaf than for redroot pigweed, sicklepod, entireleaf morningglory, or hemp sesbania. Ammonium sulfate increased prickly sida and entireleaf morningglory control but did not influence sicklepod, hemp sesbania, or barnyardgrass control. Acifluorfen applied 3 d before glyphosate or in a mixture with glyphosate reduced barnyardgrass control compared with glyphosate applied alone. Chlorimuron did not reduce efficacy. Mixtures of glyphosate and 2,4-DB controlled sicklepod, entireleaf morningglory, and barnyardgrass similar to glyphosate alone.

scholarly journals Germination Parameters of Selected Summer Weeds: Transferring of the AlertInf Model to Other Geographical Regions

Agronomy ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 292
Author(s):  
Valentina Šoštarčić ◽  
Roberta Masin ◽  
Donato Loddo ◽  
Ema Brijačak ◽  
Maja Šćepanović
Keyword(s):  
Weed Management ◽  
Field Experiments ◽  
Chenopodium Album ◽  
Seedling Emergence ◽  
Amaranthus Retroflexus ◽  
Base Temperature ◽  
Time Model ◽  
Emergence Patterns ◽  
Geographical Regions ◽  
Base Water Potential

Effective weed management depends on correct control timing, which depends on seedling emergence dynamics. Since soil temperature and soil moisture are the two main factors that determine weed germination, the hydrothermal time model can be used to predict their emergence. The aim of this study was to estimate the base temperature (Tb) and base water potential (Ψb) for the germination of Chenopodium album, Amaranthus retroflexus, Setaria pumila, and Panicum capillare collected from fields in continental Croatia and then to compare these values with those of Italian populations embedded in the AlertInf model. Germination tests were performed at seven constant temperatures (ranging from 4 to 27 °C) and eight water potentials (0.00–1.00 MPa). The estimated Tb and Ψb were 3.4 °C and −1.38 MPa for C. album, 13.9 °C and −0.36 MPa for A. retroflexus, 6.6 °C and −0.71 MPa for S. pumila, and 11.0 °C and −0.87 MPa for P. capillare, respectively. According to the criterion of overlap of the 95% confidence intervals, only the Tb of C. album and the Ψb of A. retroflexus of the Croatian and Italian populations were similar. Further field experiments should be conducted to monitor the weed emergence patterns of C. album and calibrate the AlerInf equation parameters.

scholarly journals Biological Parameters for Germination of Selected Summer Weed Species: First Step to Transfer the Hydrothermal Model Alertinf to Croatia

2021 ◽  
Author(s):  
Valentina Šoštarčić ◽  
Roberta Masin ◽  
Donato Loddo ◽  
Ema Brijačak ◽  
Maja Šćepanović
Keyword(s):  
Weed Management ◽  
Field Experiments ◽  
Chenopodium Album ◽  
Seedling Emergence ◽  
Amaranthus Retroflexus ◽  
Base Temperature ◽  
Weed Species ◽  
Time Model ◽  
Emergence Patterns ◽  
Base Water Potential

The efficacy of weed management depends on the correct control timing according to the seedling emergence dynamics. Since soil temperature and soil moisture are two main factors that determine weed germination, the hydrothermal time model can be used to predict their emergence. The aim of this study was to estimate the base temperature (Tb) and base water potential (Ψb) for germination of Chenopodium album, Amaranthus retroflexus, Setaria pumila and Panicum capillare collected from fields in continental Croatia and then to compare these values with those of Italian populations embedded in the AlertInf model. Germination tests were performed at seven constant temperatures (ranging from 4 to 27°C) and eight water potentials (0.00 to - 1.00 MPa). Estimated Tb and Ψb were 3.4°C, -1.38 MPa for C. album, 13.9°C, -0.36 MPa for A. retroflexus, 6.6°C, -0.71 MPa for S. pumila and 11.0°C, -0.87 MPa for P. capillare, respectively. According to the criterion of overlap of the 95% confidence intervals, only Tb of C. album, and Ψb of A. retroflexus were similar between Croatian and Italian populations. Further field experiments should be conducted in the Croatian field to monitor weed emergence patterns of C. album and to calibrate the AlerInf equation parameters.

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