Soybean canopy formation effects on pitted morningglory (Ipomoea lacunosa), common cocklebur (Xanthium strumarium), and sicklepod (Senna obtusifolia) emergence

Weed Science ◽  
2004 ◽  
Vol 52 (6) ◽  
pp. 954-960 ◽  
Author(s):  
Jason K. Norsworthy
Keyword(s):  
Soil Temperature ◽  
Soil Surface ◽  
Field Studies ◽  
Light Interception ◽  
Xanthium Strumarium ◽  
Weed Species ◽  
Ipomoea Lacunosa ◽  
Pitted Morningglory ◽  
Soybean Canopy ◽  
Weed Emergence

Field studies were conducted in 2002 and 2003 to determine whether canopy formation influences pitted morningglory, common cocklebur, and sicklepod emergence in surface-tilled soybean. Each weed species was broadcast seeded before planting soybean in 19- and 97-cm-wide rows. Weed emergence beneath soybean was monitored after soybean emergence and compared with weed emergence in the absence of soybean (bareground treatment). Magnitude of daily diurnal soil temperature fluctuations diminished after soybean canopy formation, and light interception by soybean was positively related to the reduction in soil temperature. Canopy formation (50% light interception) occurred 16 to 17 d later in wide compared with narrow rows in both years. The red/far-red ratio of light available to seed on or near the soil surface was reduced from as much as 1.2 in full sunlight to less than 0.1 in the presence of a dense soybean canopy. Pitted morningglory emergence was not influenced by soybean canopy formation, whereas common cocklebur and sicklepod emergence were reduced as much as 33 and 68%, respectively. Although common cocklebur and sicklepod emergence diminished after soybean canopy formation, a small portion of the seedbank of both species emerged beneath the canopy. This research indicates that in a tilled system, emergence of some weed species is diminished by presence of an overlying canopy, but emergence does not completely cease with canopy formation. Late-season emergence of sicklepod and common cocklebur beneath a soybean canopy may contribute to replenishment of the soil seedbank, especially if these late-emerging cohorts are capable of surviving until the light environment is favorable for seed production.

Absorption, Translocation, and Metabolism of Glufosinate in Transgenic and Nontransgenic Cotton, Palmer Amaranth (Amaranthus palmeri), and Pitted Morningglory (Ipomoea lacunosa)

Weed Science ◽  
2009 ◽  
Vol 57 (4) ◽  
pp. 357-361 ◽  
Author(s):  
Wesley J. Everman ◽  
Walter E. Thomas ◽  
James D. Burton ◽  
Alan C. York ◽  
John W. Wilcut
Keyword(s):  
Palmer Amaranth ◽  
Amaranthus Palmeri ◽  
Weed Species ◽  
Ipomoea Lacunosa ◽  
Leaf Stage ◽  
Intermediate Metabolism ◽  
Pitted Morningglory ◽  
Cotton Plants ◽  
Treated Leaf ◽  
Harvest Intervals

Greenhouse studies were conducted to evaluate absorption, translocation, and metabolism of14C-glufosinate in glufosinate-resistant cotton, nontransgenic cotton, Palmer amaranth, and pitted morningglory. Cotton plants were treated at the four-leaf stage, whereas Palmer amaranth and pitted morningglory were treated at 7.5 and 10 cm, respectively. All plants were harvested at 1, 6, 24, 48, and 72 h after treatment (HAT). Absorption of14C-glufosinate was greater than 85% 24 h after treatment in Palmer amaranth. Absorption was less than 30% at all harvest intervals for glufosinate-resistant cotton, nontransgenic cotton, and pitted morningglory. At 24 HAT, 49 and 12% of radioactivity was translocated to regions above and below the treated leaf, respectively, in Palmer amaranth. Metabolites of14C-glufosinate were detected in all crop and weed species. Metabolism of14C-glufosinate was 16% or lower in nontransgenic cotton and pitted morningglory; however, metabolism rates were greater than 70% in glufosinate-resistant cotton 72 HAT. Intermediate metabolism was observed for Palmer amaranth, with metabolites comprising 20 to 30% of detectable radioactivity between 6 and 72 HAT.

Glyphosate and Paraquat Effects on Weed Seed Germination and Seedling Emergence

Weed Science ◽  
1978 ◽  
Vol 26 (3) ◽  
pp. 249-251 ◽  
Author(s):  
G. H. Egley ◽  
R. D. Williams
Keyword(s):  
Seedling Emergence ◽  
Soil Surface ◽  
Amaranthus Retroflexus ◽  
Sorghum Halepense ◽  
Weed Species ◽  
Sida Spinosa ◽  
Broadleaf Species ◽  
Prickly Sida ◽  
Grass Weed ◽  
Weed Emergence

Glyphosate [N-(phosphonomethyl)glycine] (30, 125, 250 mg/L) in petri dishes had no effect on germination of prickly sida(Sida spinosaL.), velvetleaf(Abutilon theophrastiMedic), barnyardgrass [Echinocloa crus-galli(L.) Beauv.] and johnsongrass [Sorghum halepense(L.) Pers.] seeds, but additional experimentation indicated that glyphosate stimulated germination of redroot pigweed(Amaranthus retroflexusL.) seeds. Paraquat (1,1′-dimethyl-4,4′-bipyridinium ion) (30, 125, 250 mg/L) did not affect germination of the three broadleaf species, but inhibited johnsongrass and barnyardgrass germination. In the greenhouse, soil surface applications of glyphosate (1.1, 2.2, 9.0 kg/ha) did not significantly affect emergence of these five weed species when they were on or beneath the soil surface at time of treatment. Paraquat (same rates) did not affect broadleaf weed emergence but some rates inhibited grass weed emergence when the seeds were treated while on the soil surface. It is unlikely that normal field use rates of glyphosate will influence weed emergence; whereas paraquat may inhibit the emergence of some grass weeds if the herbicide contacts seeds on the soil surface.

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.

Influence of Imazapyr on the Control of Pitted Morningglory (Ipomoea lacunosa) and Johnsongrass (Sorghum halepense) with Chlorimuron, Imazaquin, and Imazethapyr

Weed Science ◽  
1988 ◽  
Vol 36 (5) ◽  
pp. 663-666 ◽  
Author(s):  
Dennis G. Riley ◽  
David R. Shaw
Keyword(s):  
Field Experiments ◽  
Sorghum Halepense ◽  
Significant Enhancement ◽  
Weed Species ◽  
Ipomoea Lacunosa ◽  
Pitted Morningglory ◽  
Better Than

Field experiments were conducted to evaluate postemergence combinations of imazethapyr, imazquin, or chlorimuron with low rates of imazapyr for Johnsongrass and pitted morningglory control. Imazapyr applied alone at rates up to 4 g ai/ha gave little or no control of either weed species. However, the addition of imazapyr to various rates of imazethapyr or imazaquin synergistically increased both johnsongrass and pitted morningglory control 8 weeks after treatment. The rates of imazethapyr or imazaquin required for significant enhancement of johnsongrass control were higher than those required for pitted morningglory control. No synergistic increases in control of either weed species were noted with mixtures of imazapyr and chlorimuron. Although not synergistic in every case, the mixtures of imazapyr at 4 g/ha with imazethapyr, imazaquin, or chlorimuron gave johnsongrass and pitted morningglory control equal to or better than the next higher rate of these herbicides applied alone. Imazapyr did not increase soybean injury or decrease yield provided by chlorimuron, imazaquin, or imazethapyr.

Control of Annual Morningglories (Ipomoeaspp.) in Soybeans (Glycine max)

Weed Science ◽  
1984 ◽  
Vol 32 (6) ◽  
pp. 813-818 ◽  
Author(s):  
Michele A. Barker ◽  
Lafayette Thompson ◽  
F. Michael Godley
Keyword(s):  
North Carolina ◽  
Soybean Seed ◽  
Field Studies ◽  
Ipomoea Hederacea ◽  
Ipomoea Lacunosa ◽  
Ipomoea Purpurea ◽  
Pitted Morningglory ◽  
Ipomoea Coccinea ◽  
Seed Yields ◽  
Over The Top

Field studies were conducted in North Carolina in 1981 and 1982 to evaluate the efficacy of postemergence over-the-top and postemergence-directed herbicides for control of five morningglory species: entireleaf [Ipomoea hederacea(L.) Jacq. var.integriusculaGray], tall [Ipomoea purpurea(L.) Roth. ♯3PHBPU], ivyleaf [Ipomoea hederacea(L.) Jacq. var.hederacea♯IPOHE], pitted [Ipomoea lacunosa(L.) ♯ IPOLA], and scarlet [Ipomoea coccinea(L.) ♯IPOCC]. The glabrous morningglories (scarlet and pitted) were more easily controlled than the pubescent morningglories (ivyleaf, tall, and entireleaf). Lower soybean injury, higher morningglory control, and greater soybean seed yields were obtained with over-the-top herbicide applications at 4 weeks after planting (WAP) than at 6 WAP. Pitted morningglory was tolerant to low rates of 2,4-DB [4-(2,4-dichlorophenoxy) butyric acid]. This herbicide applied over the top at the R1 stage of soybean growth produced low yields, probably as a result of morningglory interference and herbicide injury to the soybeans. Postemergence-directed applications of linuron [3-(3,4-dichlorophenyl)-1-methoxy-1-methylurea] and metribuzin [4-amino-6-tert-butyl-3-(methylthio-as-triazin-5(4H)-one] alone or in tank mixtures with 2,4-DB resulted in soybean injury that ranged from 12 to 36%. Highest soybean seed yields (equivalent to weed-free control) from postemergence-directed herbicides were obtained with applications of 2,4-DB, linuron, and a tank mixture of metribuzin and 2,4-DB.

Rice (Oryza sativa) Weed Control with Soil Applications of Quinclorac

1993 ◽  
Vol 7 (3) ◽  
pp. 600-604 ◽  
Author(s):  
Joe E. Street ◽  
Thomas C. Mueller
Keyword(s):  
Oryza Sativa ◽  
Weed Control ◽  
Rice Yield ◽  
Field Studies ◽  
Moist Soil ◽  
Weed Species ◽  
Application Timing ◽  
Soil Application ◽  
Pitted Morningglory ◽  
Dry Soil

Field studies were conducted from 1988 to 1990 on a Sharkey clay to evaluate residual weed control in rice with quinclorac applied PPI, PRE to dry soil, and PRE to moist soil. Quinclorac applied at 0.4 or 0.6 kg ai ha−1PPI or PRE to dry or moist soil controlled more than 80% of barnyardgrass, pitted morningglory, and hemp sesbania without rice injury. Quinclorac applied at 0.3 kg ha−1controlled these three weed species substantially but inconsistently. No rice injury was observed from any quinclorac treatment. Except for one of three years when irrigation was delayed for 7 d after PRE application to dry soil, application timing did not consistently affect weed control or rice yield.

Tillage index predicts weed seedling recruitment depth

2004 ◽  
Vol 84 (1) ◽  
pp. 319-326 ◽  
Author(s):  
R. C. Van Acker ◽  
W. J. Bullied ◽  
M. J. du Croix Sissons
Keyword(s):  
Weed Management ◽  
Seedling Recruitment ◽  
Soil Surface ◽  
Conventional Tillage ◽  
Strategy Development ◽  
Weed Species ◽  
Relative Level ◽  
Green Foxtail ◽  
Simple Estimation ◽  
Weed Emergence

The influence of tillage on the depth of weed seedling recruitment has implications for species competitive ability, weed management strategy development, and the modeling of weed emergence; characterization of this relationship could aid in the creation of field-specific models of weed seedling recruitment. A tillage index based on the percentage of residue cover remaining on the soil surface after tillage events was assessed for 44 zero-tillage and 44 conventional-tillage fields across Manitoba, Canada. This index was related to in situ measurements of seedling recruitment depth from the same fields for five annual weed species. The modeled relationship was linear and unique for each species (R2 values ranged from 0.38 to 0.71). The relationship did not differ between pre- and post-seeding measurements, or between years, except for green foxtail. Slopes of the regression lines were greater for species such as volunteer wheat, which can recruit from a great range of depths. The results of this study show that recent tillage strongly influences mean weed seedling recruitment depth, and that the recruitment depth of summer annual weed seedlings is related in a continuous and reliable manner to a simple estimation of the relative level of tillage (including seeding) applied in one season. Key words: Recruitment depth, tillage index, weed emergence, weed seedlings

Response of Pitted Morningglory (Ipomoea lacunosa) Accessions to Chlorimuron, Fomesafen, and Glyphosate

2007 ◽  
Vol 21 (1) ◽  
pp. 179-185 ◽  
Author(s):  
Daniel O. Stephenson ◽  
Lawrence R. Oliver ◽  
Jason A. Bond
Keyword(s):  
Weed Management ◽  
Field Studies ◽  
Visual Control ◽  
Geographic Locations ◽  
Ipomoea Lacunosa ◽  
West Central ◽  
Pitted Morningglory ◽  
Over The Top

Field studies were conducted in Fayetteville, AR, to determine the response of 38 pitted morningglory accessions to fomesafen, chlorimuron, and glyphosate when applied postemergence over-the-top (POT) at 9 g ai/ha, 420 g ai/ha, and 840 g ae/ha, respectively, to four-leaf, 15-cm-tall pitted morningglory. Visual control following chlorimuron application ranged from 82 to 95% 3 wk after treatment (WAT). Visual control of accessions with fomesafen ranged 34 to 84% 3 WAT. Variability in visual control following fomesafen application was documented among accessions collected from similar geographic locations in west-central and southwest Arkansas, central and southeast Louisiana, and west-central Mississippi. Glyphosate controlled pitted morningglory accessions 81 to 89% 3 WAT. Data indicate that weed management programs should be field specific where fomesafen use is intended.

Johnsongrass (Sorghum halepense) and Pitted Morningglory (Ipomoea lacunosa) Control with Imazaquin and Imazethapyr

1989 ◽  
Vol 3 (1) ◽  
pp. 95-98 ◽  
Author(s):  
Dennis G. Riley ◽  
David R. Shaw
Keyword(s):  
Sorghum Halepense ◽  
Single Application ◽  
Weed Species ◽  
Ipomoea Lacunosa ◽  
Pitted Morningglory ◽  
Better Than

Imazaquin and imazethapyr were applied postemergence to soybeans for control of 8- to 12-leaf rhizome johnsongrass and pitted morningglory in the field. At 8 weeks, johnsongrass control was 70% with 70 g ai/ha imazaquin plus 105 g ai/ha imazethapyr but was no more than 50% with a single application of either herbicide. Imazaquin at 70 g/ha plus imazethapyr at 35 g/ha interacted synergistically to provide 90% pitted morningglory control, while 140 g/ha imazaquin controlled 77%. Imazaquin at 70 g/ha with imazethapyr from 18 to 105 g/ha controlled both weed species equal to or better than that obtained with 140 g/ha imazaquin.

Decline of Weed Seeds and Seedling Emergence Over Five Years as Affected by Soil Disturbances

Weed Science ◽  
1990 ◽  
Vol 38 (6) ◽  
pp. 504-510 ◽  
Author(s):  
Grant H. Egley ◽  
Robert D. Williams
Keyword(s):  
Seedling Emergence ◽  
Soil Surface ◽  
First Year ◽  
Weed Species ◽  
Native Seed ◽  
Seed Population ◽  
Soil Disturbances ◽  
Viable Seeds ◽  
Prickly Sida ◽  
Weed Emergence

Weed emergence and viable weed seed numbers were determined in field plots during a 5-yr period where reseeding was prevented. Known numbers of seeds of seven weed species were added to the native seed population at the beginning of the study. Plots were nontilled or tilled to depths of 0, 5, 10, and 15 cm early in the spring of each year. Velvetleaf, spurred anoda, hemp sesbania, morningglory species, and pigweed species emergence was significantly greater from the nontilled plots during the first year after seeds were added to the native seed population. Tillage, regardless of depth, reduced weed emergence during the first year where seeds were added to the plots but had no effect on emergence from plots where no seeds were added. Tillage during the second through the fifth year did not affect emergence regardless of the addition of seeds. of the 5-yr emergence totals, 61 to 88% of all weeds in all plots emerged during the first year and 9 to 23% emerged during the second year. The 5-yr decline rate for emergence of all weeds was exponential. Viable seeds of prickly sida, spurges, and pigweeds in the nontilled plots declined from 590, 1531, and 4346 m−2, respectively, to zero by the third year. Tillage did not affect the decline. However, weed emergence in the field indicated that a few (1.0 to 5.6 m−2) seeds of those weeds were still viable after 3 yr. In nontilled plots, many recently added seeds were on or near the soil surface and germinated during the first year. Tillage moved many seeds to sites that were unfavorable for germination and emergence during the first year.

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