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.

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.

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.

The Effects of Naturally Occurring Phenolic Compounds on Seed Germination

Weed Science ◽  
1982 ◽  
Vol 30 (2) ◽  
pp. 206-212 ◽  
Author(s):  
Robert D. Williams ◽  
Robert E. Hoagland
Keyword(s):  
Chlorogenic Acid ◽  
Amaranthus Retroflexus ◽  
Hydroxybenzoic Acid ◽  
Weed Species ◽  
Allelopathic Potential ◽  
Sesbania Exaltata ◽  
Hydrocinnamic Acid ◽  
Hemp Sesbania ◽  
Sida Spinosa ◽  
Prickly Sida

Caffeic acid, chlorogenic acid, coumarin,p-coumaric acid, ferulic acid, fumaric acid, gallic acid, hydrocinnamic acid,p-hydroxybenzoic acid, juglone, and pyrocatechol were examined for effects on germination of nine crop and weed species: cotton (Gossypium hirsutumL.), cantaloupe (Cucumis meloL.), corn (Zea maysL.), sorghum [Sorghum bicolor(L.) Moench], hemp sesbania [Sesbania exaltata(Raf.) Cary], sicklepod (Cassia obtusifoliaL.), velvetleaf (Abutilon theophrastiMedic), prickly sida (Sida spinosaL.), and redroot pigweed (Amaranthus retroflexusL.). Germination tests with 10-3and 10-5M solutions were conducted under controlled conditions in petri dishes at 25 C in the dark. At 10-3M, coumarin, hydrocinnamic acid, juglone and pyrocatechol inhibited germination, butp-hydroxybenzaldehyde andp-hydroxybenzoic acid were not effective and others had intermediate effects. There was little effect by any compound at 10-5M. Chlorogenic acid,p-hydroxybenzaldehyde, and pyrocatechol, each combined with coumarin, inhibited germination. The combination of coumarin plusp-hydroxybenzaldehyde had an additive effect on hemp sesbania and prickly sida, inhibiting germination to a greater extent than either compound alone. The lack of inhibitory action at the higher concentration of some of these chemicals suggests they may not exhibit a high allelopathic potential.

scholarly journals Factors affecting Cyperus difformis seed germination and seedling emergence

2013 ◽  
Vol 31 (4) ◽  
pp. 823-832 ◽  
Author(s):  
A. Derakhshan ◽  
J. Gherekhloo
Keyword(s):  
Seed Germination ◽  
Integrated Management ◽  
Germination Rate ◽  
Seedling Emergence ◽  
Management Strategies ◽  
Soil Surface ◽  
Weed Species ◽  
Factors Affecting ◽  
Cyperus Difformis ◽  
Emergence Patterns

Specific knowledge about the dormancy, germination, and emergence patterns of weed species aids the development of integrated management strategies. Laboratory studies were conducted to determine the effect of several environmental factors on seed germination and seedling emergence of Cyperus difformis. Germination of freshly harvested seeds was inhibited by darkness; however, when seeds were subsequently transferred to complete light they germinated readily. Our results showed that 2 wk of cold stratification overcome the light requirement for germination. Seeds of C. difformis were able to germinate over a broad range of temperatures (25/15, 30/20, 35/25, and 40/30 ºC day/night). The response of germination rate to temperature was described as a non-linear function. Based on model outputs, the base, the optimum and the ceiling temperatures were estimated as 14.81, 37.72 and 45 ºC, respectively. A temperature of 120 ºC for a 5 min was required to inhibit 50% of maximum germination. The osmotic potential and salinity required for 50% inhibition of maximum germination were -0.47 MPa and 135.57 mM, respectively. High percentage of seed germination (89%) was observed at pH=6 and decreased to 12% at alkaline medium (pH 9) pH. Seeds sown on the soil surface gave the greatest percentage of seedling emergence, and no seedlings emerged from seeds buried in soil at depths of 1 cm.

Herbicide-Crop Rotation for Johnsongrass (Sorghum halepense) Control

Weed Science ◽  
1979 ◽  
Vol 27 (5) ◽  
pp. 479-485 ◽  
Author(s):  
J. E. Dale ◽  
J. M. Chandler
Keyword(s):  
Crop Rotation ◽  
Field Experiments ◽  
Amaranthus Retroflexus ◽  
Cyperus Rotundus ◽  
Sorghum Halepense ◽  
Purple Nutsedge ◽  
Cropping Sequence ◽  
Sesbania Exaltata ◽  
Common Purslane ◽  
Sida Spinosa

The feasibility of herbicide and crop rotation for the control of johnsongrass [Sorghum halepense(L.) Pers.] in corn (Zea maysL.) was studied in field experiments. Light infestations of johnsongrass were initially present, but it became the predominant weed after 4 yr of continuous corn treated with atrazine [2-chloro-4-(ethylamino)-6-(isopropylamine)-s-triazine], cyanazine {2-[[4-chloro-6-(ethylamino)-s-triazin-2-yl]amino]-2-methylpropionitrile}, and linuron [3-(3,4-dichlorophenyl)-1-methoxy-1-methylurea], alone and in combinations at rates of 2.24, 2.24, and 0.84 kg/ha, respectively. The infestation of johnsongrass was effectively controlled by growing corn in rotation with cotton (Gossypium hirsutumL.) in a cropping sequence of corn-cotton-cotton-corn, in which trifluralin (α,α,α-trifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine), fluometuron [1,1-dimethyl-3-(α,α,α-trifluoro-m-tolyl)urea] and MSMA (monosodium methanearsonate) at 0.56, 2.24, and 2.24 kg/ha respectively, were used for weed control in cotton. In the corn-cotton-cotton-corn cropping sequence, the herbicide treatments also prevented increases in the populations of other indigeneous weeds including prickly sida (Sida spinosaL.), prostrate spurge (Euphorbia supinaRaf.), spotted spurge (Euphorbia maculataL.), common purslane (Portulaca oleraceaL.), tall morningglory [Ipomoea purpurea(L.) Roth], common cocklebur (Xanthium pensylvanicumWallr.), spurred anoda[Anoda cristata(L.) Schlecht.], hemp sesbania [Sesbania exaltata(Raf.) Cory], redroot pigweed (Amaranthus retroflexusL.), goosegrass [Eleusine indica(L.) Gaertn.], junglerice [Echinochloa colonum(L.) Link], large crabgrass [Digitaria sanguinalis(L.) Scop.], and purple nutsedge (Cyperus rotundusL.).

Interference between pigweed (Amaranthusspp.), barnyardgrass(Echinochloa crus-galli), and soybean (Glycine max)

Weed Science ◽  
1998 ◽  
Vol 46 (5) ◽  
pp. 533-539 ◽  
Author(s):  
Paul Cowan ◽  
Susan E. Weaver ◽  
Clarence J. Swanton
Keyword(s):  
Competitive Ability ◽  
Field Experiments ◽  
Yield Loss ◽  
Seedling Emergence ◽  
Growth Time ◽  
Weed Species ◽  
Soybean Yield ◽  
Competitive Index ◽  
Loss Maximum ◽  
Weed Emergence

Field experiments were conducted to determine the influence of time of emergence and density of single and multispecies populations of pigweed and barnyardgrass on soybean yield and competitive abilities of pigweed and barnyardgrass. Pigweed and barnyardgrass were established at selected densities within 12.5 cm on either side of the soybean row. Pigweed and barnyardgrass seeds were sown concurrently with soybean and at the cotyledon stage of soybean growth. Time and density of pigweed and barnyardgrass seedling emergence relative to soybean influenced the magnitude of soybean yield loss. Maximum soybean yield loss ranged from 32 to 99%, depending upon time of emergence relative to soybean. Pigweed was more competitive than barnyardgrass across all locations, years, and time of weed emergence. When pigweed was assigned a competitive index of 1 on a scale from 0 to 1, the competitive ability of barnyardgrass ranged from 0.075 to 0.40 of pigweed, depending upon location and time of emergence. This is the first multiple weed species study to include time of weed emergence relative to the crop. Competitive index values for multiple weed species must be calculated from field experiments in which weeds are grown with the crop under differing environmental conditions.

Fusarium lateritium: A Pathogen of Spurred Anoda (Anoda cristata), Prickly Sida (Sida spinosa), and Velvetleaf (Abutilon theophrasti)

Weed Science ◽  
1981 ◽  
Vol 29 (6) ◽  
pp. 629-631 ◽  
Author(s):  
H. Lynn Walker
Keyword(s):  
Abutilon Theophrasti ◽  
Weed Species ◽  
Disease Symptoms ◽  
Naturally Occurring ◽  
Fusarium Lateritium ◽  
Hibiscus Trionum ◽  
Sida Spinosa ◽  
Stem Lesions ◽  
Prickly Sida ◽  
Anoda Cristata

An isolate ofFusarium lateritium(Nees) emend. Snyder and Hansen was associated with naturally occurring disease of spurred anoda [Anoda cristata(L.) Schlecht.] and prickly sida (Sida spinosaL.) plants. In greenhouse inoculation studies, theFusariumisolate was pathogenic to healthy spurred anoda and prickly sida plants. The disease symptoms were characterized by leaf, stem, and root lesions. The stem lesions enlarged with time and formed cankers that often girdled the stems and killed inoculated plants. In host-range studies, velvetleaf (Abutilon theophrastiMedic.), Venice mallow (Hibiscus trionumL.), okra [Abelmoschus esculentus(L.) Moench], and hollyhock [Althaea rosea(L.) Cav.] were also susceptible to the pathogen. This is the first report of these six species as hosts for this pathogen. Corn (Zea maysL.), cotton (Gossypium hirsutumL. andG. barbadenseL.), soybean [Glycine max(L.) Merr.], and 18 other representative crop and weed species in eight families were resistant to the pathogen.F. lateritiummay be a useful biological herbicide for susceptible malvaceous weeds.

Weed Seed and Seedling Reductions by Soil Solarization by Transparent Polyethylene Sheets

Weed Science ◽  
1983 ◽  
Vol 31 (3) ◽  
pp. 404-409 ◽  
Author(s):  
Grant H. Egley
Keyword(s):  
Soil Depth ◽  
Cyperus Rotundus ◽  
Soil Solarization ◽  
Grass Species ◽  
Purple Nutsedge ◽  
Trianthema Portulacastrum ◽  
Maximum Temperatures ◽  
Sida Spinosa ◽  
Prickly Sida ◽  
Weed Emergence

Solarization by means of transparent polyethylene sheets for 1 week in mid-summer significantly (P = 0.05) reduced numbers of viable prickly sida (Sida spinosaL.), common cocklebur (Xanthium pensylvanicumWallr.), velvetleaf (Abutilon theophrastiMedic.) and spurred anoda [Anoda cristata(L.) Schlect.] seeds remaining after burial in soil. Solarization treatments for 1 to 4 weeks significantly reduced the total weed emergence of prickly sida, pigweeds (Amaranthusspecies), spurred anoda, morningglories (Ipomoeaspecies), horse purslane (Trianthema portulacastrumL.), and various grass species from natural seed populations for the growing season by 64 to 98%. Purple nutsedge (Cyperus rotundusL.) emergence was increased by solarization in some instances. It was not determined if the increased emergence was from tubers or seeds. Maximum temperatures at the 1.3-cm soil depth under the polyethylene sheets reached 65 to 69C for 3 to 4 h of the mid-afternoon on clear days as compared with 43 to 50C at 1.3 cm in the soils that were not covered. Surface soil-moisture levels were also elevated under the polyethylene covers. Although solarization did not eliminate dormant weed seeds from the germination zone, the treatment killed nondormant seeds and greatly reduced the number of weed seedlings that otherwise would have emerged.

Banded herbicide, rotary hoeing and cultivation effects on weed populations in ridge-tilled soybean

2006 ◽  
Vol 21 (3) ◽  
pp. 151-158 ◽  
Author(s):  
Thomas W. Jurik
Keyword(s):  
Seedling Emergence ◽  
Amaranthus Retroflexus ◽  
Weed Species ◽  
Soybean Yield ◽  
Setaria Faberi ◽  
Giant Foxtail ◽  
Significant Difference ◽  
Tillage System ◽  
Polygonum Pensylvanicum ◽  
Ridge Tillage

Can banded herbicide be eliminated in ridge-tilled soybean (Glycine max)? The effects of banded herbicide, rotary hoeing and cultivation on weed populations and soybean yield in a ridge-tillage system were tested on three farms in Iowa, USA in 1989 and 1990. In 1989, plots either had no herbicide or had herbicide banded in the row at planting in mid-May; all plots received two rotary hoeings and two cultivations. In 1990, treatments were banded herbicide with no rotary hoeing, banded herbicide with one rotary hoeing, and no herbicide with one or two rotary hoeings; all plots received two or three cultivations. In both years, over all weed species [primarily giant foxtail (Setaria faberi), Pennsylvania smartweed (Polygonum pensylvanicum) and redroot pigweed (Amaranthus retroflexus)], seedling emergence was highest in late May and early June, with few seedlings emerging after mid-June. Weed populations were highest in May and June, after which rotary hoeing and cultivation reduced weed numbers in all plots. There were no consistent differences among treatments in weed numbers in early August for the 2 years. In both years, there was no significant difference in soybean yield among treatments. Within-farm mean yields ranged from 2.26 to 3.01 Mg ha−1among farms in 1989 and from 2.07 to 2.93 Mg ha−1among farms in 1990. Ridge-tillage without herbicide was generally equivalent to ridge-tillage with banded herbicide, with respect to total number of weeds and number of broad-leaved weeds remaining in August after tillage, and to soybean yield.

Factors Affecting Buffalobur (Solanum rostratum) Seed Germination and Seedling Emergence

Weed Science ◽  
2009 ◽  
Vol 57 (5) ◽  
pp. 521-525 ◽  
Author(s):  
Shouhui Wei ◽  
Chaoxian Zhang ◽  
Xiangju Li ◽  
Hailan Cui ◽  
Hongjuan Huang ◽  
...  
Keyword(s):  
Seed Germination ◽  
Light Exposure ◽  
Soil Depth ◽  
Seedling Emergence ◽  
Soil Surface ◽  
Distribution Area ◽  
Burial Depth ◽  
Weed Species ◽  
Continuous Darkness ◽  
Invasive Weed

Buffalobur is a noxious and invasive weed species native to North America. The influence of environmental factors on seed germination and seedling emergence of buffalobur were evaluated in laboratory and greenhouse experiments. The germination of buffalobur seeds occurred at temperatures ranging from 12.5 to 45 C, with optimum germination attained between 25 and 35 C. Buffalobur seeds germinated equally well under both a 14-h photoperiod and continuous darkness; however, prolonged light exposure (≥ 16 h) significantly inhibited the seed germination. Buffalobur seed is rather tolerant to low water potential and high salt stress, as germination was 28 and 52% at osmotic potentials of −1.1 MPa and salinity level of 160 mM, respectively. Medium pH has no significant effect on seed germination; germination was greater than 95% over a broad pH range from 3 to 10. Seedling emergence was higher (85%) for seeds buried at a soil depth of 2 cm than for those placed on the soil surface (32%), but no seedlings emerged when burial depth reached 8 cm. Knowledge of germination biology of buffalobur obtained in this study will be useful in predicting the potential distribution area and developing effective management strategies for this species.

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