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South Dakota State University

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Articles 31 - 44 of 44

Full-Text Articles in Weed Science

Early Season Weed Suppression In Buckwheat Using Clopyralid, Ona Sakaliene, Sharon A. Clay, William C. Koskinen, Gediminas Almantas Jan 2008

Early Season Weed Suppression In Buckwheat Using Clopyralid, Ona Sakaliene, Sharon A. Clay, William C. Koskinen, Gediminas Almantas

Agronomy, Horticulture and Plant Science Faculty Publications

Currently there are no herbicides registered for direct application to buckwheat for broadleaf weed control. This 4-yr Lithuanian study examined weed control using several rates of clopyralid alone or combined with a single rate of desmedipham. Most applications were applied at the 1-leaf stage of crop growth, however, one rate of clopyralid was applied pre-emergence (PRE) in 2 of the 4 yr. Buckwheat injury was evident within a few days after application (or emergence) with all treatments, but by harvest, no symptoms were evident. In the 2 yr with greatest weed densities, densities were reduced with increasing clopyralid rates alone …


Common Waterhemp Growth And Fecundity As Influenced By Emergence Date And Competing Crop, E. Uscanga-Mortera, S. Clay, F. Forcella, J. Gunsolus Aug 2007

Common Waterhemp Growth And Fecundity As Influenced By Emergence Date And Competing Crop, E. Uscanga-Mortera, S. Clay, F. Forcella, J. Gunsolus

Agronomy, Horticulture and Plant Science Faculty Publications

Common waterhemp (Amarathus rudis Sauer) is a frequent weed in glyphosate-resistant (GR) crops in the midwestern USA due, in part, to the delayed emergence of its seedlings. Variable waterhemp emergence was simulated by transplanting seedlings into both corn (Zea mays L.) and soybean [Glycine max (L.) Merr.] and bare plot areas at differing crop growth stages during two growing seasons in western Minnesota. Growth and fecundity were measured. As expected, late planted weeds produced little dry matter and few seeds, and competition from corn or soybean reduced waterhemp dry weight and fecundity by 90% compared with isolated plants. Interestingly, common …


Microarray Analysis Of Late-Season Velvetleaf (Abutilon Theophrasti) Effect On Corn, David P. Horvath, Robert Gulden, Sharon A. Clay Dec 2006

Microarray Analysis Of Late-Season Velvetleaf (Abutilon Theophrasti) Effect On Corn, David P. Horvath, Robert Gulden, Sharon A. Clay

Agronomy, Horticulture and Plant Science Faculty Publications

Microarray analysis was used to identify changes in gene expression in corn leaves collected from plants at the V11–14 growth stage that resulted from competition with velvetleaf. The plants were grown in field plots under adequate N (addition of 220 kg N ha1) and irrigation to minimize N and water stress. Consequently, only differences resulting from competition for micronutrients, light, and perhaps allelopathic stress were anticipated. Genes involved in carbon and nitrogen utilization, photosynthesis, growth and development, oxidative stress, signal transduction, responses to auxin and ethylene, and zinc transport were repressed in corn growing in competition with velvetleaf. …


Spatial Distribution, Temporal Stability, And Yield Loss Estimates For Annual Grasses And Common Ragweed (Ambrosia Artimisiifolia) In A Corn/Soybean Production Field Over Nine Years, Sharon A. Clay, Bruce Kreutner, David E. Clay, Cheryl Reese, Jonathan Kleinjan, Frank Forcella Jan 2006

Spatial Distribution, Temporal Stability, And Yield Loss Estimates For Annual Grasses And Common Ragweed (Ambrosia Artimisiifolia) In A Corn/Soybean Production Field Over Nine Years, Sharon A. Clay, Bruce Kreutner, David E. Clay, Cheryl Reese, Jonathan Kleinjan, Frank Forcella

Agronomy, Horticulture and Plant Science Faculty Publications

Weeds generally occur in patches in production fields. Are these patches spatially and temporally stable? Do management recommendations change on the basis of these data? The population density and location of annual grass weeds and common ragweed were examined in a 65-ha corn/soybean production field from 1995 to 2004. Yearly treatment recommendations were developed from field means, medians, and kriging grid cell densities, using the hyperbolic yield loss (YL) equation and published incremental YL values (I ), maximum YL values (A), and YL limits of 5, 10, or 15%. Mean plant densities ranged from 12 to 131 annual grasses m22 …


Sampling Weed Spatial Variability On A Fieldwide Scale, Sharon A. Clay, G. Jason Lems, Frank Forcella, Michael M. Ellsbury, C. Gregg Carlson, David E. Clay Dec 1999

Sampling Weed Spatial Variability On A Fieldwide Scale, Sharon A. Clay, G. Jason Lems, Frank Forcella, Michael M. Ellsbury, C. Gregg Carlson, David E. Clay

Agronomy, Horticulture and Plant Science Faculty Publications

Site-specific weed management recommendations require knowledge of weed species, density, and location in the field. This study compared several sampling techniques to estimate weed density and distribution in two 65-ha no-till Zea mays–Glycine max rotation fields in eastern South Dakota. The most common weeds (Setaria viridis, Setaria glauca, Cirsium arvense, Ambrosia artemisiifolia, and Polygonum pensylvanicum) were counted by species in 0.1-m2 areas on a 15- by 30-m (1,352 points in each field) or 30- by 30-m (676 points in each field) grid pattern, and points were georeferenced and data spatially analyzed. Using different sampling approaches, weed populations were estimated by …


Influence Of Deleterious Rhizobacteria On Leafy Spurge (Euphorbia Esula) Roots, Mark A. Brinkman, Sharon A. Clay, Robert J. Kremer Dec 1999

Influence Of Deleterious Rhizobacteria On Leafy Spurge (Euphorbia Esula) Roots, Mark A. Brinkman, Sharon A. Clay, Robert J. Kremer

Agronomy, Horticulture and Plant Science Faculty Publications

Rhizobacteria have been shown to be phytotoxic to leafy spurge in laboratory assays. This field study investigated the influence of two strains of Pseudomonas fluorescens [Trevisan, (Migula)], deleterious rhizobacteria (DRB), on root weight, root bud number, and root carbohydrate content of leafy spurge at three sites located in northeast and north-central South Dakota. Soils were inoculated with 2 g of starch-based granules containing no bacteria or starch granules containing 108colony-forming units (cfu)/g of either bacterial strain LS102 (Montana origin) or LS174 (South Dakota origin). Bacterial strains were detected on root samples from treated areas. Root weight and root carbohydrate content …


Influence Of Crop Rotation, Tillage, And Management Inputs On Weed Seed Production, George O. Kegode, Frank Forcella, Sharon Clay Apr 1999

Influence Of Crop Rotation, Tillage, And Management Inputs On Weed Seed Production, George O. Kegode, Frank Forcella, Sharon Clay

Agronomy, Horticulture and Plant Science Faculty Publications

Approaches to crop production that successfully reduce weed seed production can benefit farming systems by reducing management inputs and costs. A 5-yr rotation study was conducted in order to determine the effects that interactions between crop rotation, tillage, and amount of herbicide and fertilizer (management inputs) have on annual grass and broad-leaved weed seed production and fecundity. There were 10 crop rotation and tillage system combinations and three levels of management inputs (high, medium, and low). Green and yellow foxtail were the major weed species, and together they yielded between 76 and 93% of collected weed seeds. From 1990 to …


Leafy Spurge Biological Control Using Black Dot Flea Beetles And Deleterious Rhizobacteria: Final Report Submitted To South Dakota Department Of Agriculture Weed And Pest Control, Sharon A. Clay, Mark A. Brinkman, Robert J. Kramer, Jan J. Jackson, Nels H. Granholm Apr 1998

Leafy Spurge Biological Control Using Black Dot Flea Beetles And Deleterious Rhizobacteria: Final Report Submitted To South Dakota Department Of Agriculture Weed And Pest Control, Sharon A. Clay, Mark A. Brinkman, Robert J. Kramer, Jan J. Jackson, Nels H. Granholm

Agronomy, Horticulture and Plant Science Faculty Publications

Size of leafy spurge (Euphorbia esula L) roots and their location in the soil profile are important factors relating to survival offirst-instar black dot flea beetle (Aphthona nigriscutis Foudras) larvae. First-instar larvae must find leafy spurge roots between 1 to 4 mm diam in the first 2 days after hatching from eggs for survival. In field studies, we ddermined that most flea beetle larvae reside within 7.6 em ofthe soil surface. Their location in the upper areas ofthe soil profile allows accessibility to desirable size roots, however the larvae are more susceptible to freezing temperatures in this region. Overall, there …


Weed Seed Bank Emergence Across The Corn Belt, Frank Forcella, Robert G. Wilson, Jack Dekker, Robert J. Kramer, John Cardina, Randy L. Anderson, David Alm, Karen A. Renner, R. Gordon Harvey, Sharon Clay, Douglas D. Buhler Feb 1997

Weed Seed Bank Emergence Across The Corn Belt, Frank Forcella, Robert G. Wilson, Jack Dekker, Robert J. Kramer, John Cardina, Randy L. Anderson, David Alm, Karen A. Renner, R. Gordon Harvey, Sharon Clay, Douglas D. Buhler

Agronomy, Horticulture and Plant Science Faculty Publications

Field experiments, conducted from 1991 to 1994, generated information on weed seedbank emergence for 22 site-years from Ohio to Colorado and Minnesota to Missouri. Early spring seedbank densities were estimated through direct extraction of viable seeds from soil cores. Emerged seedlings were recorded periodically, as were daily values for air and soil temperature, and precipitation. Percentages of weed seedbanks that emerged as seedlings were calculated from seedbank and seedling data for each species, and relationships between seedbank emergence and microclimatic variables were sought. Fifteen species were found in 3 or more site-years. Average emergence percentages (and coefficients of variation) of …


Leafy Spurge - A Review, Sharon A. Clay, Chad M. Scholes Jan 1997

Leafy Spurge - A Review, Sharon A. Clay, Chad M. Scholes

Agronomy, Horticulture and Plant Science Faculty Publications

Leafy spurge (Euphorbia esula L.) is a perennial herbaceous weed that infests millions of acres of range and pasture in the northern Great Plains. It outcompetes grasses and lowers land productivity because cattle will not graze infested areas even if spurge makes up only 10% of the vegetative biomass. This presentation will cover the history, taxonomy, and phenology of leafy spurge. A discussion of chemical, mechanical, and biocontrol techniques that aid in leafy spurge management will also be included.


Analysis Of Spatial Distribution Of Canada Thistle (Cirsium Arvense) In Notill Soybean (Glycine Max), B. L. Broulik, J. Lems, S. A. Clay, D. E. Clay, M. M. Ellsbury Jan 1997

Analysis Of Spatial Distribution Of Canada Thistle (Cirsium Arvense) In Notill Soybean (Glycine Max), B. L. Broulik, J. Lems, S. A. Clay, D. E. Clay, M. M. Ellsbury

Agronomy, Horticulture and Plant Science Faculty Publications

The nonuniform spatial distribution of weeds across a field landscape complicates sampling and modeling, but allows site specific rather than broadcast management of weed populations. Where weeds are aggregated, densities measured at random locations are not independent, but rather spatially related or autocorrelated. Geostatistical methods were used to describe and map nonrandom distribution and variation of shoot density across ten well established patches of Canada thistle, a perennial weed, in a 65 hectare notillage soybean field in Moody county, South Dakota in 1996. Canada thistle densities were determined by counting the number of shoots present in a 20 by 50 …


Atrazine And Alachlor Adsorption Characteristics To Benchmark Soil Series In Eastern South Dakota, Z. Liu, S. A. Clay, J. Gaffney, D. Malo Jan 1997

Atrazine And Alachlor Adsorption Characteristics To Benchmark Soil Series In Eastern South Dakota, Z. Liu, S. A. Clay, J. Gaffney, D. Malo

Agronomy, Horticulture and Plant Science Faculty Publications

Corn, grain sorghum, and soybean are grown on about six million acres in eastern South Dakota each year. Two herbicides used routinely for weed control are atrazine(6-chloro-N-ethyl-N’-(1-methylethyl)-1,3,5-triazine-2,4-diamine) in corn and grain sorghum and alachlor (2-chloro-N-(2,6-diethylphenyl)-N-(methoxymethyl)acetamide) in all three crops. Six benchmark soil series that include a majority of the cropped acres treated with these herbicides are the Egan, Moody, Nora, and Brandt silty clay loams, and Clarno and Enet loams. Batch adsorption studies determined atrazine and alachlor binding characteristics to these soils and aids in assessing the amount of herbicide available for movement. These data also provide a basis for …


Factors Affecting Atrazine Fate In North Central U.S. Soils, W. C. Koskinen, Sharon Clay Jan 1997

Factors Affecting Atrazine Fate In North Central U.S. Soils, W. C. Koskinen, Sharon Clay

Agronomy, Horticulture and Plant Science Faculty Publications

Atrazine (6-chloro-N-ethyl-N′-(l-methylethyl)-l,3,5-triazine-2,4-diamine) is a herbicide of the triazine family used for controlling broadleaf and some grassy weeds in corn and sorghum. Since its introduction in the late 1950s, atrazine has been a popular herbicide because it is relatively inexpensive and, in most cases, gives good season-long weed control. It can be applied pre-or postemergence and is often tank mixed with grass herbicides, such as alachlor (2-chloro-N-(2,6-diethylphenyl-N-(methoxymethyl)acetamide), metolachlor(2-chloro-N-(2-2ethyl-6-methylphenyl)-N-(2-methoxy-l-methylethyl) acetamide), butylate (S-ethyl bis(2-methylpropyl)carbamothioate), or EPTC (S-ethyl dipropylcarbamothioate), or with other broadleaf herbicides, such as dicamba (3,6-dichloro-2-methoxybenzoic …


Characterization Of Alachlor And Atrazine Desorption From Soils, Sharon A. Clay, William C. Koskinen Jan 1990

Characterization Of Alachlor And Atrazine Desorption From Soils, Sharon A. Clay, William C. Koskinen

Agronomy, Horticulture and Plant Science Faculty Publications

Herbicide desorption isotherms may be affected by the amount of nondesorbable herbicide present in soil. Nondesorbable alachlor (as determined after methanol extraction) generally increased on a Waukegan silt loam (Typic Hapludolls) and a Ves clay loam (Udic Haplustolls) during five 0.01 M CaCl₂ desorptions. Atrazine was totally extracted with methanol from the Waukegan soil after one desorption using 0.01 M CaCl₂. However, after five desorptions with 0.01 M CaCl₂ an average of 5.5 and 15.5% of the total recovered atrazine from two atrazine application rates was methanol nondesorbable from the Waukegan and Ves soils, respectively. Freundlich desorption isotherms adjusted for …