Effect of weed growth stage and adjuvant on the efficacy of fomesafen and bentazon

Weed Science ◽  
2003 ◽  
Vol 51 (6) ◽  
pp. 1016-1021 ◽  
Author(s):  
Robin R. Bellinder ◽  
Marija Arsenovic ◽  
Denis A. Shah ◽  
Bradley J. Rauch
Keyword(s):  
New York ◽  
Growth Stage ◽  
Field Experiments ◽  
New York State ◽  
Field Studies ◽  
Weed Species ◽  
Eastern Black Nightshade ◽  
Black Nightshade ◽  
Weed Growth ◽  
Annual Weeds

The efficacies of bentazon and fomesafen in controlling annual weeds in dry and edible pod beans in New York State were investigated in greenhouse and field experiments. Dose responses to bentazon and fomesafen were studied for four weed species (ragweed, velvetleaf, eastern black nightshade, and hairy nightshade) under greenhouse conditions. Herbicides were applied at cotyledon to two-, two- to four-, and four- to six–true leaf stages, both with and without a crop oil concentrate (bentazon) or a nonionic surfactant (fomesafen). Field studies were conducted for 2 yr for all weed species except eastern black nightshade, for which no adequate field populations were found. Field studies confirmed greenhouse results, indicating that weed control could be improved by the use of an adjuvant, but there were exceptions. In general, adjuvant usage improved the efficacy of fomesafen more than it did with bentazon. The minimum rates of herbicide required for effective and consistent control was dependent on the particular combination of weed species, herbicide and its rate of application, growth stage at which the application was made, and adjuvant usage.

Response of Selected Weed Species to Postemergence Imazethapyr and Bentazon

1995 ◽  
Vol 9 (2) ◽  
pp. 236-242 ◽  
Author(s):  
Troy A. Bauer ◽  
Karen A. Renner ◽  
Donald Penner
Keyword(s):  
Weed Control ◽  
Field Research ◽  
Dry Weight ◽  
Field Studies ◽  
Weed Species ◽  
Eastern Black Nightshade ◽  
Black Nightshade ◽  
Redroot Pigweed ◽  
Treated Leaf ◽  
Petroleum Oil

Imazethapyr and bentazon were applied with petroleum oil adjuvant in a factorial arrangement to weed species in greenhouse and field research to determine if postemergence weed control by imazethapyr was antagonized when bentazon was tank-mixed. Tank-mixing 840 g/ha of bentazon with 13 or 27 g/ha of imazethapyr increased redroot pigweed and eastern black nightshade dry weight as compared to Colby's expected values in the greenhouse. However, weed control was not reduced in field studies. Subsequent greenhouse studies indicated that soil interception and resulting root uptake of imazethapyr increased redroot pigweed control. Bentazon decreased foliar absorption of14C-imazethapyr by 15% and translocation of14C from the treated leaf by more than 50% compared tol4C-imazethapyr applied alone.

Tomato (Lycopersicon esculentum) and Eastern Black Nightshade (Solanum ptycanthum) Tolerance to Aciflurofen

1987 ◽  
Vol 1 (4) ◽  
pp. 278-281 ◽  
Author(s):  
Stanley F. Gorski ◽  
Monica K. Wertz
Keyword(s):  
Lycopersicon Esculentum ◽  
Sodium Salt ◽  
Growth Stage ◽  
Field Experiments ◽  
Foliar Injury ◽  
Leaf Stage ◽  
Eastern Black Nightshade ◽  
Nitrobenzoic Acid ◽  
Solanum Ptycanthum ◽  
Black Nightshade

Field experiments were conducted to determine the influence of growth stage on tolerance of seeded tomatoes (Lycopersicon esculentumMill.) and of eastern black nightshade (Solanum ptycanthumDun. #3SOLPT) to the sodium salt of acifluorfen {5-[2-chloro-4-(trifluoromethyl)phenoxy]-2-nitrobenzoic acid} at low use rates. Tomatoes as young as the 2 true-leaf stage exhibited some tolerance to acifluorfen at rates of 0.14 kg ae/ha and less. Rates of 0.28 and 0.56 kg/ha caused increased phytotoxicity; however, yield was not greatly reduced. At the 8-leaf stage, foliar injury was slight and existed only at the highest rates tested; however, tomato yields were reduced. Control of black nightshade at the 2-leaf stage was acceptable at rates as low as 0.14 kg/ha. When nightshade was at the 5-leaf stage, 0.28 and 0.56 kg/ha rates provided acceptable control − 87% and 96%, respectively. Nightshade in the 10-leaf stage was not controlled effectively at rates below 0.56 kg/ha.

scholarly journals Evaluation of Herbaceous Perennials as Weed Suppressive Groundcovers for Use Along Roadsides or in Landscapes

2005 ◽  
Vol 23 (4) ◽  
pp. 198-203 ◽  
Author(s):  
Seok Hyun Eom ◽  
Andrew F. Senesac ◽  
Irene Tsontakis-Bradley ◽  
Leslie A. Weston
Keyword(s):  
New York ◽  
Field Experiments ◽  
New York State ◽  
Soil Surface ◽  
Early Spring ◽  
Light Transmittance ◽  
Herbaceous Perennials ◽  
Weed Growth ◽  
Successful Establishment ◽  
Lamiastrum Galeobdolon

Abstract Fifteen herbaceous perennials were evaluated in field experiments in two New York State locations to determine their utility in roadside and landscape areas as weed suppressive groundcovers. Four species, Alchemilla mollis, Nepeta x faassenii, Phlox subulata, and Solidago sphacelata were strongly weed suppressive in both managed (weeds removed) plots and unmanaged (weeds not removed) plots. Weed suppressivity of perennial groundcovers was significantly increased in year two in both locations when perennials were well established. The most suppressive perennials showed several similar characteristics likely associated with their successful establishment. Successful groundcovers possessed dense foliage which strongly reduced light transmittance at the soil surface and emerged relatively early in spring. Lamiastrum galeobdolon and Thymus praecox proved to be more successful over a 2-year period when managed by weed removal in early spring. Although Leymus arenarius, a relatively tall monocot, also inhibited weed growth, this species demonstrated invasive characteristics due to its spread outside plots by fast-growing rhizomes.

Glufosinate Efficacy on Annual Weeds Is Influenced by Rate and Growth Stage

1997 ◽  
Vol 11 (3) ◽  
pp. 484-488 ◽  
Author(s):  
Gregory J. Steckel ◽  
Loyd M. Wax ◽  
F. William Simmons ◽  
William H. Phillips
Keyword(s):  
Growth Stage ◽  
Field Experiments ◽  
Weed Species ◽  
Application Timing ◽  
Common Lambsquarters ◽  
Tolerant Species ◽  
Giant Foxtail ◽  
Annual Weeds

Field experiments were conducted in 1993, 1994, and 1995 to determine the effects of glufosinate rate and application timing on giant foxtail, common lambsquarters, common cocklebur, and Pennsylvania smartweed control in absence of a crop. Glufosinate at 140 g ai/ha controlled less than 80% of the weed species evaluated. When glufosinate rate was increased to 420 g/ha and applied to 10-cm giant foxtail, control was greater than 80% all 3 yr of the study. Applications made to 10-cm plants resulted in 80% or greater control for common cocklebur all 3 yr and Pennsylvania smartweed 2 of the 3 yr with 420 and 560 g/ha, respectively. Common lambsquarters was the most tolerant species evaluated and was not consistently controlled acceptably (> 80%), even with glufosinate at rates of 560 g/ha. Control with glufosinate at 420 or 560 g/ha was most effective when applied at the 10-cm weed height compared either to the 5- or 15-cm weed height.

Row Spacing and Seeding Rate Effects on Eastern Black Nightshade (Solanum Ptycanthum) and Soybean

2007 ◽  
Vol 21 (1) ◽  
pp. 124-130 ◽  
Author(s):  
Adrienne M. Rich ◽  
Karen A. Renner
Keyword(s):  
Dry Weight ◽  
Field Studies ◽  
Production Costs ◽  
Row Spacing ◽  
Seeding Rate ◽  
Soybean Yield ◽  
Eastern Black Nightshade ◽  
Solanum Ptycanthum ◽  
Black Nightshade ◽  
Rate Effects

Reducing seeding rates in 19- or 76-cm row soybean below the optimum rate may reduce soybean competitiveness with weeds, and indirectly increase production costs to the grower. Field studies in 2001 and 2002 evaluated the effect of soybean seeding rate and row spacing on the emergence, growth, and competitiveness of eastern black nightshade (EBN) in soybean. EBN emergence ceased within 45 d after planting (DAP), and was similar across soybean seeding rates and row spacing. EBN control by glyphosate was not affected by soybean population or row spacing. Soybean planted in 19-cm rows was more competitive with EBN, regardless of seeding rate. Increasing the soybean seeding rate in 76-cm rows from 185,000 seeds/ha to 432,000 seeds/ha reduced EBN dry weight threefold at East Lansing and nearly twofold at Clarksville in 2002. There was no increase in EBN density or dry weight in 19-cm row soybean planted at 308,000 seeds/ha compared with 556,000 seeds/ha, whereas a seeding rate of 432,000 seeds/ha in 76-cm row soybean did not suppress EBN dry weight or increase soybean yield in the presence of EBN compared with a seeding rate of 308,000 seeds/ha.

The critical weed-free period in glyphosate-resistant soybean in Ontario is similar to previous estimates using glyphosate-susceptible soybean

2019 ◽  
Vol 99 (4) ◽  
pp. 437-443
Author(s):  
Nader Soltani ◽  
Robert E. Nurse ◽  
Amit J. Jhala ◽  
Peter H. Sikkema
Keyword(s):  
Growth Stage ◽  
Field Experiments ◽  
Yield Loss ◽  
Growth Stages ◽  
Weed Species ◽  
Weed Biomass ◽  
Weed Density ◽  
Weed Interference ◽  
Beginning Of Flowering ◽  
Minimal Reduction

A study consisting of 13 field experiments was conducted during 2014–2016 in southwestern Ontario and southcentral Nebraska (Clay Center) to determine the effect of late-emerging weeds on the yield of glyphosate-resistant soybean. Soybean was maintained weed-free with glyphosate (900 g ae ha−1) up to the VC (cotyledon), V1 (first trifoliate), V2 (second trifoliate), V3 (third trifoliate), V4 (fourth trifoliate), and R1 (beginning of flowering) growth stages, after which weeds were allowed to naturally infest the soybean plots. The total weed density was reduced to 24%, 63%, 67%, 72%, 76%, and 92% in Environment 1 (Exeter, Harrow, and Ridgetown) when soybean was maintained weed-free up to the VC, V1, V2, V3, V4, and R1 soybean growth stages, respectively. The total weed biomass was reduced by 33%, 82%, 95%, 97%, 97%, and 100% in Environment 1 (Exeter, Harrow, and Ridgetown) and 28%, 100%, 100%, 100%, 100%, and 100% in Environment 2 (Clay Center) when soybean was maintained weed-free up to the VC, V1, V2, V3, V4, and R1 stages, respectively. The critical weed-free periods for a 2.5%, 5%, and 10% yield loss in soybean were the V1–V2, VC–V1, and VC–V1 soybean stages in Environment 1 (Exeter, Harrow, and Ridgetown) and V2–V3, V2–V3, and V1–V2 soybean stages in Environment 2 (Clay Center), respectively. For the weed species evaluated, there was a minimal reduction in weed biomass (5% or less) when soybean was maintained weed-free beyond the V3 soybean growth stage. These results shows that soybean must be maintained weed-free up to the V3 growth stage to minimize yield loss due to weed interference.

Biologically effective rate of saflufenacil/dimethenamid-p in soybean (Glycine max)

2012 ◽  
Vol 92 (3) ◽  
pp. 517-531 ◽  
Author(s):  
Robert T. Miller ◽  
Nader Soltani ◽  
Darren E. Robinson ◽  
Trevor E. Kraus ◽  
Peter H. Sikkema
Keyword(s):  
Glycine Max ◽  
Environmental Conditions ◽  
Field Studies ◽  
Effective Rate ◽  
Weed Species ◽  
Green Foxtail ◽  
Equivalent Control ◽  
Lamb’S Quarters ◽  
Set Up ◽  
Annual Weeds

Miller, R. T., Soltani, N., Robinson, D. E., Kraus, T. E. and Sikkema, P. H. 2012. Biologically effective rate of saflufenacil/dimethenamid- in soybean ( Glycine max ). Can. J. Plant Sci. 92: 517–531. A total of five field studies were conducted over a 2-yr period (2009, 2010) at three Ontario locations to determine the biologically effective rate of saflufenacil/dimethenamid-p applied preemergence (PRE) for the control of annual weeds in soybean. The rate of saflufenacil/dimethenamid-p required for the control of annual weeds was influenced by environmental conditions. With adequate moisture and above-average temperatures in 2010, between 224 and 374 g a.i. ha−1 of saflufenacil/dimethenamid-p was required for 80% control of common ragweed, common lamb's quarters, and green foxtail 4 wk after treatment (WAT). In contrast, below-average temperatures and excessive moisture in 2009 resulted in higher rates of saflufenacil/dimethenamid-p being necessary for the same level of weed control. Pigweed species were least affected by environmental conditions after application at 4 WAT with only 245 g a.i. ha−1 required for 80% control in both years. By 11 WAT, 320 g a.i. ha−1 or less of saflufenacil/dimethenamid-p was required to achieve 80% control of these species in 2010, while 845 g a.i. ha−1 or more was needed in 2009 for equivalent control. The potential of saflufenacil/dimethenamid-p as a set-up treatment prior to a postemergence (POST) glyphosate application was also examined. Excellent full season control of all weed species was achieved with saflufenacil/dimethenamid-p applied PRE followed by glyphosate POST. However, there was no difference in yield when saflufenacil/dimethenamid-p was followed by glyphosate POST compared with a single glyphosate POST application.

Host Range Alteration of the Bioherbicidal FungusAlternaria crassawith Fruit Pectin and Bant Filtrates

Weed Science ◽  
1994 ◽  
Vol 42 (3) ◽  
pp. 487-491 ◽  
Author(s):  
C. Douglas Boyette ◽  
Hamed K. Abbas
Keyword(s):  
Host Range ◽  
Host Specificity ◽  
Water Soluble ◽  
Weed Species ◽  
Eastern Black Nightshade ◽  
Black Nightshade ◽  
Hemp Sesbania ◽  
Greenhouse Tests

In greenhouse tests, the host specificity ofAlternaria crassa(Sacc.) Rands, a mycoherbicide for jimsonweed was altered by the addition of water-soluble filtrates of jimsonweed and hemp sesbania or fruit pectin to fungal conidia suspensions. Several crop and weed species that were resistant to the fungus alone exhibited various degrees of susceptibility following these amendments, with 100% mortality occurring to the weeds hemp sesbania, showy crotalaria, and eastern black nightshade when treated with the fungus/pectin mixture. Nonhost plants that were inoculated with conidial mixtures amended with sucrose or cellulose were not affected. Modification of host specificity of this pathogen could have an influence on its bioherbiddal potential

Strategies for Control of Horseweed (Conyza canadensis) and Other Winter Annual Weeds in No-Till Corn

2009 ◽  
Vol 23 (3) ◽  
pp. 379-383 ◽  
Author(s):  
Gregory R. Armel ◽  
Robert J. Richardson ◽  
Henry P. Wilson ◽  
Thomas E. Hines
Keyword(s):  
Field Studies ◽  
Conyza Canadensis ◽  
Weed Species ◽  
Annual Bluegrass ◽  
No Till ◽  
Winter Annual ◽  
Winter Annual Weeds ◽  
Annual Weeds

Field studies were conducted to determine if mesotrione alone or in combinations with other corn herbicides would control horseweed and other winter annual weeds associated with no-till corn. Mesotrione alone controlled horseweed 52 to 80% by 3 wk after treatment (WAT); however, by 7 WAT control diminished to between 37 to 68%, depending on mesotrione rate. Mesotrione at 0.16 kg ai/ha plus atrazine at 0.28 kg ai/ha controlled 99% of horseweed and annual bluegrass and 88% of yellow woodsorrel. Combinations of mesotrione at 0.16 kg/ha plus acetochlor at 1.79 kg ai/ha plus 1.12 kg ai/ha glyphosate (trimethylsulfonium salt of glyphosate) or 0.7 kg ai/ha paraquat provided 93% or greater control of all three weed species. Glyphosate alone also controlled all weed species 97 to 99%, while paraquat alone provided 99% control of annual bluegrass, 72% control of horseweed, and 36% control of yellow woodsorrel. Mixtures of paraquat plus acetochlor improved control of horseweed (93%) and yellow woodsorrel (73%) over control with either herbicide applied alone.

Effect of Herbicides on Field Violet (Viola arvensis) in Direct-Seeded Spring Wheat

2005 ◽  
Vol 19 (2) ◽  
pp. 359-371 ◽  
Author(s):  
Rory F. Degenhardt ◽  
Dean Spaner ◽  
K. Neil Harker ◽  
William R. Mcgregor ◽  
Linda M. Hall
Keyword(s):  
Spring Wheat ◽  
Crop Production ◽  
Field Experiments ◽  
Plant Density ◽  
Dry Weight ◽  
Effective Control ◽  
Weed Species ◽  
Weed Growth ◽  
Direct Seeded ◽  
Cereal Fields

The agrestal field violet, a pervasive weed in Europe, has been identified in reduced-tillage cereal fields in Alberta. The efficacy of herbicides in direct-seeded spring wheat was assessed on natural field violet infestations in Alberta in 2002 and 2003. Only fluroxypyr + 2,4-D, applied postemergence, provided control of field violet in 2002 when rainfall was limiting. Over both years, this herbicide combination reduced biomass by 59 to 69% and plant density by 83 to 91%, relative to nontreated plots. The herbicides metsulfuron, sulfosulfuron, and thifensulfuron + tribenuron only suppressed weed growth under drought conditions in 2002 but controlled the weed in 2003 when rainfall was greater, reducing plant density by 82 to 92% and rendering remaining plants sterile. Suppression was also observed with MCPA + mecoprop + dicamba in 2002 and 2003 and with metribuzin only in 2003. Effective control of field violet was conferred by a pre–crop emergence application of glyphosate at 445 g ae/ha in 2003, the only year that this treatment was evaluated. Activity of herbicides on three- to four-leaf seedlings was also evaluated in a greenhouse dose– response assay. All herbicides had greater efficacy in the greenhouse, and those that provided control in situ reduced field violet dry weight by 85% at less than the recommended rate used in field experiments. Management of field violet is possible with herbicides registered for use on spring wheat in Alberta. However, the weed does not appear to cause significant crop production losses; hence, herbicide selection should be based on knowledge of all weed species present within the field.

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