scholarly journals Corn–Velvetleaf (Abutilon theophrasti) Interference Is Affected by Sublethal Doses of Postemergence Herbicides

Weed Science ◽  
2007 ◽  
Vol 55 (5) ◽  
pp. 491-496 ◽  
Author(s):  
Brescia R. M. Terra ◽  
Alexander R. Martin ◽  
John L. Lindquist
Keyword(s):  
Seed Production ◽  
Field Experiments ◽  
Yield Loss ◽  
Maximum Height ◽  
Corn Yield ◽  
Negative Effects ◽  
Capsule Production ◽  
Yield Information ◽  
Sublethal Doses ◽  
Postemergence Herbicides

Injury to weeds from sublethal doses of POST herbicides may reduce the effect of weed interference on crop yield. Information on how herbicide dose influences weed mortality, growth, and seed production is needed to assess the potential benefit of applying reduced herbicide doses. Field experiments were conducted at Mead, NE, in 2001 and 2002 to quantify velvetleaf mortality, growth, and corn–velvetleaf interference in response to varying doses of three POST herbicides. Untreated velvetleaf at six densities (0, 1, 3, 6, 12, and 20 plants m−1 corn row) was grown in mixture with corn to establish a baseline corn–velvetleaf interference relationship. Treated velvetleaf at a density of 20 plants m−1 row received one of five doses of dicamba, halosulfuron, or flumiclorac. Untreated velvetleaf height, biomass, and seed capsule production were greater in 2002 than 2001 and declined with increasing velvetleaf density in both years. Corn yield was not affected by untreated velvetleaf in 2001, but yield loss increased with increasing velvetleaf density in 2002. Mortality of herbicide-treated velvetleaf was 56% greater in 2001 than 2002 and increased with increasing herbicide dose. Maximum height of treated velvetleaf was similar for all treatments in 2001 but declined with increasing herbicide dose in 2002. Biomass and seed production of treated velvetleaf varied among herbicides in 2002 and decreased with increasing dose. Corn yield was not influenced by velvetleaf in 2001, but yield loss in response to herbicide-treated velvetleaf declined with increasing herbicide dose in 2002. Results show that the assumption that weeds surviving herbicide application are as competitive as untreated weeds is incorrect. Reduction in growth and resource consumption by herbicide-damaged weeds reduced the negative effects of weeds on corn.

Annual weed competitiveness as affected by preemergence herbicide in corn

Weed Science ◽  
2006 ◽  
Vol 54 (1) ◽  
pp. 156-165 ◽  
Author(s):  
Konanani B. Liphadzi ◽  
J. Anita Dille
Keyword(s):  
Seed Production ◽  
Crop Yield ◽  
Field Experiments ◽  
Yield Loss ◽  
Palmer Amaranth ◽  
Growth And Yield ◽  
Yield Response ◽  
Corn Yield ◽  
Herbicide Application ◽  
Crop Yield Loss

Competitiveness of weeds that survive a PRE herbicide application (escaped weeds) might be altered because of herbicide injury. As a result, potential crop yield loss may be reduced. Field experiments were conducted at Ashland Bottoms, KS, in 2001 and 2002 and at Rossville, KS, in 2002. The objectives were to quantify corn growth and yield response to Palmer amaranth or velvetleaf competition, with or without isoxaflutole (0.03 kg ha−1) or flumetsulam (0.04 kg ha−1) application, and to determine seed production of Palmer amaranth or velvetleaf as affected by PRE herbicide. Palmer amaranth and velvetleaf densities ranged from 0 to 6 and 0 to 32 plants m−1of corn row, respectively. At Ashland Bottoms in 2002, corn height at tasseling decreased with increasing Palmer amaranth (1.58 cm weed−1m−1) and velvetleaf (1.32 cm weed−1m−1) density when no herbicide was applied. With flumetsulam application, each increase in velvetleaf density reduced corn height by 0.4 cm. Escaped Palmer amaranth and velvetleaf were shorter than untreated plants at corn tasseling. At Rossville in 2002, Palmer amaranth that escaped isoxaflutole or flumetsulam application caused 13% corn yield loss (YL) at a density of 3 plants m−1. In contrast, corn YL from untreated Palmer amaranth at the same density was 30%. At Ashland Bottoms in 2002, velvetleaf that escaped flumetsulam caused 3% corn YL at a density of 3 plants m−1compared with 38% YL caused by untreated velvetleaf at the same density. Seed production of Palmer amaranth was independent of density or herbicide treatment, whereas production of velvetleaf seed increased with density, with or without flumetsulam. The study showed that corn YL from both Palmer amaranth and velvetleaf that escaped a PRE herbicide was less than from untreated weeds, but seed production by escaped weeds was similar to that of untreated weeds.

Influence of barnyardgrass (Echinochloa crus-galli) time of emergence and density on corn (Zea mays)

Weed Science ◽  
1997 ◽  
Vol 45 (2) ◽  
pp. 276-282 ◽  
Author(s):  
Aca C. Bosnic ◽  
Clarence J. Swanton
Keyword(s):  
Leaf Area ◽  
Seed Production ◽  
Weed Management ◽  
Field Experiments ◽  
Yield Loss ◽  
Seedling Emergence ◽  
Integrated Weed Management ◽  
Corn Yield ◽  
Area Index ◽  
Leaf Stage

Barnyardgrass is a serious weed problem in cornfields in Ontario. Field experiments were conducted at two locations in 1994 and 1995 to determine the influence of emergence time and barnyardgrass density on corn yield loss, leaf area at 50% silking, and barnyardgrass seed production. Selected barnyardgrass densities up to 200 plants m−1were established within 12.5 cm on either side of the corn row. Barnyardgrass seeds were planted concurrently with corn and at the 3- to 5- or 1- to 2-leaf stage of corn growth in 1994 and 1995, respectively. Barnyardgrass density and seedling emergence relative to corn influenced the magnitude of corn yield loss. Maximum corn grain yield loss ranged from 26 to 35% for early emerging barnyardgrass, and less than 6% yield loss occurred from barnyardgrass seedlings emerging later than the 4-leaf stage of corn growth. Changes in corn leaf area index at 50% silking reflected the level of barnyardgrass competition in corn. Maximum leaf area reduction ranged from 21 to 23%. Barnyardgrass seed production varied with time of seedling emergence and density. Ten barnyardgrass plants emerging up to the 3-leaf stage of corn growth produced 14,400 to 34,600 seeds m−2compared to only 1,200 to 2,800 seeds m−2from plants emerging after the 4-leaf corn stage. The results of this study are essential in the development of an integrated weed management strategy for corn.

scholarly journals Tolerance and velvetleaf (Abutilon theophrasti) suppressive ability of two old and two modern corn (Zea mays) hybrids

Weed Science ◽  
1998 ◽  
Vol 46 (5) ◽  
pp. 569-574 ◽  
Author(s):  
John L. Lindquist ◽  
David A. Mortensen
Keyword(s):  
Weed Management ◽  
Field Experiments ◽  
Yield Loss ◽  
Maximum Yield ◽  
Management Program ◽  
Integrated Weed Management ◽  
Photon Flux ◽  
Corn Yield ◽  
Area Index ◽  
Capsule Production

Improved crop tolerance and weed suppressive ability are tactics that may reduce the negative effect of weeds on crop yield. Irrigated field experiments were conducted to compare leaf area index (LAI), intercepted photosynthetic photon flux (PPF), and relative tolerance and velvetleaf suppressive ability among two old (circa 1940) and two modern corn hybrids. Each hybrid was grown in monoculture and in mixture with velvetleaf at 1, 4, 16, and 40 plants m−1row. Plants were periodically harvested in monoculture plots to obtain estimates of corn LAI, and PPF interception was measured. Variation in hybrid tolerance to velvetleaf competition for light was evaluated by comparing among hybrids the coefficients of a regression of corn yield loss on velvetleaf density. Velvetleaf seed capsule production in the presence of each hybrid was compared to evaluate variation in velvetleaf suppressive ability among hybrids. Maximum corn yield loss was 32% lower for the two old hybrids, and velvetleaf capsule production was reduced by 62% at low velvetleaf densities in 1995 compared to the modern hybrids. In 1996, yield loss of the modern hybrid 3394 was 74% lower than that of the other three hybrids at low velvetleaf densities, whereas maximum yield loss of the old hybrid 336 was 44% lower at high densities. Velvetleaf capsule production did not vary among hybrids at any velvetleaf density in 1996. Hybrids with greater tolerance and velvetleaf suppressive ability also had greater LAI and PPF interception, suggesting optimized corn LAI and PPF interception may be useful in an integrated weed management program.

scholarly journals Effect of nitrogen addition on the comparative productivity of corn and velvetleaf (Abutilon theophrasti)

Weed Science ◽  
2006 ◽  
Vol 54 (02) ◽  
pp. 354-363 ◽  
Author(s):  
Darren C. Barker ◽  
Stevan Z. Knezevic ◽  
Alex R. Martin ◽  
Daniel T. Walters ◽  
John L. Lindquist
Keyword(s):  
Leaf Area ◽  
Field Experiments ◽  
Yield Loss ◽  
Biomass Accumulation ◽  
Nitrogen Addition ◽  
Corn Yield ◽  
N Addition ◽  
Area Index ◽  
Nitrogen Levels ◽  
Weed Growth

Weeds that respond more to nitrogen fertilizer than crops may be more competitive under high nitrogen (N) conditions. Therefore, understanding the effects of nitrogen on crop and weed growth and competition is critical. Field experiments were conducted at two locations in 1999 and 2000 to determine the influence of varying levels of N addition on corn and velvetleaf height, leaf area, biomass accumulation, and yield. Nitrogen addition increased corn and velvetleaf height by a maximum of 15 and 68%, respectively. N addition increased corn and velvetleaf maximum leaf area index (LAI) by up to 51 and 90%. Corn and velvetleaf maximum biomass increased by up to 68 and 89% with N addition. Competition from corn had the greatest effect on velvetleaf growth, reducing its biomass by up to 90% compared with monoculture velvetleaf. Corn response to N addition was less than that of velvetleaf, indicating that velvetleaf may be most competitive at high levels of nitrogen and least competitive when nitrogen levels are low. Corn yield declined with increasing velvetleaf interference at all levels of N addition. However, corn yield loss due to velvetleaf interference was similar across N treatments except in one site–year, where yield loss increased with increasing N addition. Corn yield loss due to velvetleaf interference may increase with increasing N supply when velvetleaf emergence and early season growth are similar to that of corn.

Cultural Practices Affecting Season-Long Weed Control in Irrigated Corn (Zea mays)

Weed Science ◽  
1984 ◽  
Vol 32 (4) ◽  
pp. 460-467 ◽  
Author(s):  
Russell S. Moomaw ◽  
Alex R. Martin
Keyword(s):  
Zea Mays ◽  
Weed Control ◽  
Seed Production ◽  
Field Experiments ◽  
Cultural Practices ◽  
Fine Sand ◽  
Corn Yield ◽  
Weed Seed ◽  
Weed Growth ◽  
Herbicide Use

Season-long weed control has been a goal of some producers of irrigated corn (Zea maysL.) to reduce competition, lessen weed seed production, facilitate crop harvest, improve water efficiency (particularly with furrow irrigation), and improve aesthetic properties of fields. Field experiments were conducted for 3 yr on sprinkler-irrigated corn on a loamy fine sand. Five herbicides applied at layby generally provided season-long control of grass weeds and reduced weed seed production up to 100%. Pendimethalin [N-(1-ethylpropyl)-3,4-dimethyl-2,6-dinitrobenzenamine] was particularly effective. Yields of irrigated corn were not increased by layby herbicide application. Use of corn rows spaced 91 cm apart and use of a shorter, early-maturing, horizontal-leaf corn cultivar resulted in greater weed growth and weed seed production than did use of 76-cm rows and a taller, full-season, upright-leaf corn cultivar. After nearly complete weed control with herbicides for 2 yr, withholding herbicide use in the third year allowed weed growth which reduced corn yield. Indications were that weed control efforts need to be continuous in irrigated corn production.

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.

Corn and Palmer amaranth (Amaranthus palmeri) Interactions with Nitrogen in Dryland and Irrigated Environments

Weed Science ◽  
2013 ◽  
Vol 61 (2) ◽  
pp. 249-258 ◽  
Author(s):  
Ella K. Ruf-Pachta ◽  
Dwain M. Rule ◽  
J. Anita Dille
Keyword(s):  
Soil Moisture ◽  
Crop Production ◽  
Field Experiments ◽  
Yield Loss ◽  
Palmer Amaranth ◽  
Parameter Estimates ◽  
Corn Yield ◽  
N Application ◽  
Nitrogen Concentrations ◽  
N Rates

Palmer amaranth influences selection of crop production practices such as irrigation, nitrogen (N) application, and weed control. The objectives of this research were to determine if Palmer amaranth was more responsive to applied N than corn and if this differed under dryland and irrigated conditions in Kansas. Field experiments were conducted near Manhattan, KS, in 2005 and 2006 to evaluate the influence of N rate and Palmer amaranth densities when grown with corn in two soil moisture environments. A very drought-stressed environment and a well-watered environment occurred in 2006, while both environments in 2005 were intermediate. Dryland weed-free corn yields were 46.5% of irrigated corn yields at the high N rate across years. Irrigated corn yields responded to increasing N rates. In the presence of Palmer amaranth, parameter estimates I and A for the yield loss relationship were not different across N rates for each environment and year except 2006 where 100% yield loss was estimated in dryland compared to 62.5% loss in irrigated environment at high N rates. In three of four environment-years, N rate did not affect the corn yield loss relationship with weed density. In 2006 irrigated environment, greater N rates had less corn yield loss caused by Palmer amaranth. By corn anthesis, weed-free corn biomass was 167.5% greater in irrigated than dryland environments in 2006. Palmer amaranth with no corn increased its biomass by 373 and 361% as N rate increased in 2005 and 2006, respectively. Nitrogen concentrations in plant tissues of corn or weed increased similarly as N rates increased from 0 to 224 kg N ha−1, thus highlighting that both corn and Palmer amaranth responded similarly to increasing N. In general, soil moisture environment was most critical when determining potential corn yield, followed by Palmer amaranth density and N rate.

Effects of hybrid susceptibility and inoculation timing on Goss’s bacterial wilt and leaf blight severity and corn yield

Plant Disease ◽  
2021 ◽  
Author(s):  
Elizabeth C Bauske ◽  
Andrew J Friskop
Keyword(s):  
Disease Severity ◽  
Bacterial Wilt ◽  
Field Experiments ◽  
Yield Loss ◽  
Leaf Blight ◽  
Corn Yield ◽  
Yield Losses ◽  
Sequential Combination ◽  
High Level ◽  
Growing Region

Goss’s bacterial wilt and leaf blight (Goss’s wilt) of corn is the most important corn disease in North Dakota (ND), and yield loss due to the disease has not been reliably quantified in northern corn growing regions. To help quantify the amount of yield loss caused by Goss’s wilt, a total of six field experiments were conducted from 2015 to 2017. Experiments were designed in a randomized complete block with a split plot arrangement. Hybrids served as main plots and Clavibacter nebraskensis (Cn) inoculation timings as sub-plots. Three hybrids were used and classified as a susceptible, moderately susceptible, and resistant. Inoculation timings included a non-inoculated control, six to ten leaf collars (V6 to V10), reproductive silk stage (R1), or a sequential combination of V6 to V10 and R1. A high level of disease (greater than 50% on susceptible hybrid) occurred in three experiments, a low level of disease (less than 5% on susceptible hybrid) in one experiment, and no disease was reported in two experiments. A combined analysis of the high disease experiments indicated yield losses of 34 to 41% on the susceptible hybrid when Cn inoculation occurred at V6 to V10. Yield losses of 22 to 25% occurred on the moderately susceptible hybrid when C. nebraskensis inoculation occurred at V6 to V10, and statistical differences in yield loss were not found among inoculations timings on the resistant hybrid. Correlation analyses suggest that for every 1% increase in R1 disease severity on the susceptible hybrid, yield was reduced by 117 kg/ha (1.9 bu/A). The current study further demonstrates the importance of hybrid resistance and provides updated yield loss information on Goss’s wilt in a northern corn growing region.

Functional relationships between giant ragweed (Ambrosia trifida) interference and sweet corn yield and ear traits

Weed Science ◽  
2006 ◽  
Vol 54 (5) ◽  
pp. 948-953 ◽  
Author(s):  
Martin M. Williams ◽  
John B. Masiunas
Keyword(s):  
Field Experiments ◽  
Yield Loss ◽  
Sweet Corn ◽  
Initial Slope ◽  
Hyperbolic Model ◽  
Corn Yield ◽  
Fresh Market ◽  
Ambrosia Trifida ◽  
Functional Relationships ◽  
Giant Ragweed

Field experiments were conducted to quantify functional relationships between giant ragweed density and sweet corn yield and ear traits. A rectangular hyperbolic model was fit to yield loss measured in terms of marketable ear mass, appropriate for the processing industry, and boxes of 50 marketable ears, relevant to the fresh market industry. The initial slope of the hyperbolic yield loss function (I), which describes the linear portion of yield loss as weed density (weeds per square meter) approaches zero, was 119 for loss of ear mass and 97 for loss of boxes of ears. Furthermore, 10 of 12 ear traits including green ear mass, husked ear mass, ear length, filled ear length, ear width, number of kernels per row, number of rows, kernel depth, kernel mass, and kernel moisture content were significantly affected by giant ragweed interference.

scholarly journals Common lambsquarters (Chenopodium album) interference with corn across the northcentral United States

Weed Science ◽  
2004 ◽  
Vol 52 (6) ◽  
pp. 1034-1038 ◽  
Author(s):  
David W. Fischer ◽  
R. Gordon Harvey ◽  
Thomas T. Bauman ◽  
Sam Phillips ◽  
Stephen E. Hart ◽  
...  
Keyword(s):  
United States ◽  
Field Experiments ◽  
Yield Loss ◽  
Management Decision ◽  
Yield Reduction ◽  
Model Parameters ◽  
Corn Yield ◽  
Data Set ◽  
Common Lambsquarters ◽  
Weed Density

Variation in crop–weed interference relationships has been shown for a number of crop–weed mixtures and may have an important influence on weed management decision-making. Field experiments were conducted at seven locations over 2 yr to evaluate variation in common lambsquarters interference in field corn and whether a single set of model parameters could be used to estimate corn grain yield loss throughout the northcentral United States. Two coefficients (IandA) of a rectangular hyperbola were estimated for each data set using nonlinear regression analysis. TheIcoefficient represents corn yield loss as weed density approaches zero, andArepresents maximum percent yield loss. Estimates of both coefficients varied between years at Wisconsin, andIvaried between years at Michigan. When locations with similar sample variances were combined, estimates of bothIandAvaried. Common lambsquarters interference caused the greatest corn yield reduction in Michigan (100%) and had the least effect in Minnesota, Nebraska, and Indiana (0% yield loss). Variation inIandAparameters resulted in variation in estimates of a single-year economic threshold (0.32 to 4.17 plants m−1of row). Results of this study fail to support the use of a common yield loss–weed density function for all locations.

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