scholarly journals Light Quality Effect on Corn Growth as Influenced by Weed Species and Nitrogen Rate

2016 ◽  
Vol 9 (1) ◽  
pp. 15 ◽  
Author(s):  
Thomas R. Butts ◽  
Joshua J. Miller ◽  
J. Derek Pruitt ◽  
Bruno C. Vieira ◽  
Maxwel C. Oliveira ◽  
...  
Keyword(s):  
Weed Management ◽  
Light Quality ◽  
Spectral Response ◽  
Shoot Biomass ◽  
Limiting Factor ◽  
Weed Species ◽  
Fibrous Root ◽  
Response Curves ◽  
Early Season ◽  
Greenhouse Study

<p>Corn-weed competition has often been characterized as the competition for limited resources such as light quantity, water, and nutrients. However, growing evidence suggests that light quality, specifically the red:far red ratio (R:FR), is a crucial component to corn-weed interactions. Additionally, a reduction in the R:FR has shown to down-regulate plant genes similarly to a nitrogen (N) deficient environment. A greenhouse study was conducted to evaluate the effect of N stress and R:FR from common waterhemp, velvetleaf, and volunteer corn on corn growth and development. The R:FR for all three weed species tended to be similar but lower than a weed-free treatment. However, observations from the spectral response curves demonstrated significant changes in the patterns of light reflected from each weed species. In the N-sufficient environment, early-season (V5 corn growth stage) R:FR from all three weed species reduced corn height, leaf chlorophyll content, and shoot biomass while increasing fibrous root biomass. However, in the N-deficient environment, no effects were observed on corn growth from changes in light quality, indicating N stress was a greater limiting factor. These results highlight the importance of the critical weed-free period and the need for proper early-season weed management.</p>

Influence of Two Herbicides on Soybean Cyst Nematode (Heterodera glycines) Reproduction on Henbit (Lamium amplexicaule) Roots

2013 ◽  
Vol 27 (1) ◽  
pp. 41-46 ◽  
Author(s):  
Rodrigo Werle ◽  
Mark L. Bernards ◽  
Loren J. Giesler ◽  
John L. Lindquist
Keyword(s):  
Soybean Cyst Nematode ◽  
Block Design ◽  
Dry Weight ◽  
The United States ◽  
Cyst Nematode ◽  
Shoot Biomass ◽  
Herbicide Application ◽  
Weed Species ◽  
Time Of Application ◽  
Greenhouse Study

Soybean cyst nematode (SCN) is the most yield-limiting pathogen of soybean in the United States. Henbit is a prevalent winter annual weed species in no-till fields and is reported to be an alternative host of SCN. A greenhouse study was conducted to evaluate how the development of SCN on henbit roots was affected by herbicide mode of action and time of herbicide application. Henbit plants were grown in watertight pots placed in a water bath bench that kept soil temperature constant (27 ± 1 C) during the study. Ten d after transplanting, pots were inoculated with approximately 1,000 SCN eggs. At 7, 14, or 21 d after inoculation (DAI), henbit plants were sprayed with recommended dose of either glyphosate (870 g ae ha−1) or 2,4-D (1,070 g ae ha−1). The experiment was arranged in a randomized complete block design with five replications per treatment, and two experimental runs separated in time. At 28 DAI, the total number of SCN cysts and eggs, and plant shoot and root dry weight per pot were determined. Henbit root and shoot biomass increased as the time of herbicide application was delayed. Glyphosate reduced root biomass more than 2,4-D, but no differences in shoot biomass were detected. The number of SCN cysts per henbit plant and eggs per cyst increased as the herbicide application was delayed from 7 to 21 DAI. Glyphosate reduced the number of cysts found on henbit roots more than 2,4-D, especially at earlier application times. On plants treated with glyphosate, SCN-females produced only half the number of eggs of SCN-females on henbit plants treated with 2,4-D, regardless of time of application. These results indicate that early control of henbit plants, especially with glyphosate, can reduce SCN reproduction potential in SCN infested fields.

Predicted Corn Yield Loss Due to Weed Competition Prior to Postemergence Herbicide Application on Wisconsin Farms

2013 ◽  
Vol 27 (1) ◽  
pp. 54-62 ◽  
Author(s):  
Nathanael D. Fickett ◽  
Chris M. Boerboom ◽  
David E. Stoltenberg
Keyword(s):  
Weed Management ◽  
Yield Loss ◽  
Economic Loss ◽  
The United States ◽  
Yield Potential ◽  
Weed Competition ◽  
Corn Yield ◽  
Herbicide Application ◽  
Weed Species ◽  
Early Season

Approximately 50% of the genetically modified herbicide-resistant corn hectares in the United States are treated only with POST-applied herbicides for weed management. Although a high degree of efficacy can be obtained with POST-applied herbicides, delayed timing of application may result in substantial corn yield loss. Our goal was to characterize on-farm corn–weed communities prior to POST herbicide application and estimate potential corn-yield loss associated with early-season corn–weed competition. In 2008 and 2009, field surveys were conducted across 95 site-years in southern Wisconsin and recorded weed species, density, and height in addition to crop height, growth stage, and row spacing. WeedSOFT® was used to predict corn yield loss. Common lambsquarters, velvetleaf, dandelion, common ragweed, andAmaranthusspecies were the five most abundant broadleaf weed species across site-years, present in 92, 86, 59, 45, and 44% of all fields, respectively, at mean densities of 19, 3, 3, 4, and 3 plants m−2, respectively. Mean plant heights among these species were 17 cm or less. Grass and sedge species occurred in 96% of fields at a mean density of 25 plants m−2and height of 7 cm. The mean and median of total weed density across site-years were 96 and 52 plants m−2, with heights of 14 and 13 cm, respectively. Mean predicted corn yield loss was 4.5% with a mean economic loss of $62 ha−1. However, predicted yield loss was greater than 5% on one-third of the site-years, with a maximum of 26%. These results indicate that delayed application of POST herbicides has led to corn yield loss due to early-season weed-crop competition on a substantial number of fields across southern Wisconsin, and suggest that management tactics need to be improved to protect corn yield potential fully.

Response of glyphosate-resistant kochia (Kochia scoparia L. Schrad.) to alternative herbicides

2014 ◽  
Vol 94 (8) ◽  
pp. 1407-1411 ◽  
Author(s):  
Nikki Burton ◽  
Scott W. Shirriff ◽  
Hugh J. Beckie
Keyword(s):  
Acetolactate Synthase ◽  
Shoot Biomass ◽  
Western Canada ◽  
Weed Species ◽  
Kochia Scoparia ◽  
Oilseed Crops ◽  
Greenhouse Study ◽  
Herbicide Treatments ◽  
Chemical Fallow ◽  
Als Inhibitor

Burton, N., Shirriff, S. W. and Beckie, H. J. 2014. Response of glyphosate-resistant kochia (Kochia scoparia L. Schrad.) to alternative herbicides. Can. J. Plant Sci. 94: 1407–1411. A greenhouse study was conducted to examine the response of glyphosate-resistant (GR) plus acetolactate synthase (ALS) inhibitor-resistant kochia to five post-emergence herbicide treatments commonly used to control the weed species in chemical fallow, cereals, or oilseed crops in western Canada. The treatments, which were applied to two GR kochia biotypes and one non-GR (susceptible) biotype, included the labeled rate of dicamba, dicamba/fluroxypyr, dicamba/diflufenzopyr, MCPA/bromoxynil, and glufosinate. Both GR and non-GR biotypes responded similarly to each of the herbicide treatments. Although both GR biotypes were sensitive to the herbicides, MCPA/bromoxynil was the most effective treatment in reducing shoot biomass 3 wk after application (99%), followed by glufosinate (91%) then the dicamba mixtures (82%). Dicamba alone only suppressed kochia biomass (76% reduction).

scholarly journals Identification of Weed-Suppressive Tomato Cultivars for Weed Management

2021 ◽  
Author(s):  
Isabel Schlegel Werle ◽  
Edicarlos Castro ◽  
Carolina Pucci ◽  
Bhawna Soni Chakraborty ◽  
Shaun R Broderick ◽  
...  
Keyword(s):  
Weed Management ◽  
Dry Weight ◽  
Palmer Amaranth ◽  
Weed Species ◽  
Yellow Nutsedge ◽  
Solanum Lycopersicum L ◽  
Greenhouse Study ◽  
Weed Suppressive Ability ◽  
Tomato Cultivars ◽  
Large Crabgrass

The present study aims to identify tomato (Solanum lycopersicum L.) cultivars with weed-suppressive ability against target weed species in the tomato growing season. A greenhouse study was conducted with 17 tomato cultivars and target weeds Palmer amaranth (Amaranthus palmeri S. Wats), yellow nutsedge (Cyperus esculentus L.), and large crabgrass (Digitaria sanguinalis L.). Tomato plants and weed species were grown in the same pot. The height, chlorophyll, and dry weight biomass of the weeds were measured 28 days after sowing. The largest effect of tomato interference was on Palmer amaranth. Cultivar 15 reduced Palmer amaranth height, chlorophyll, and biomass by 58, 28, and 83%, respectively. Chlorophyll percentage of yellow nutsedge seedlings was suppressed by 15% by cultivar 64, whereas 13% of its height was reduced by cultivar 20. Cultivar 15 reduced biomass of yellow nutsedge by 40%. The percentage of chlorophyll of large crabgrass was reduced by 22% with cultivar 5, whereas the height and biomass were reduced by 35 and 44% with cultivars 38 and 63, respectively. Factoring all parameters evaluated, cultivars 38, 33, and 7 were most suppressive against the problematic weed species in tomato.

Influence of Early-Season Yield Loss Predictions from WeedSOFT®and Soybean Row Spacing on Weed Seed Production from a Mixed-Weed Community

2004 ◽  
Vol 18 (2) ◽  
pp. 412-418 ◽  
Author(s):  
Andrew A. Schmidt ◽  
William G. Johnson
Keyword(s):  
Seed Production ◽  
Crop Yield ◽  
Weed Management ◽  
Yield Potential ◽  
Management Decision ◽  
Yield Reduction ◽  
Weed Seed ◽  
Weed Species ◽  
Early Season ◽  
Giant Foxtail

Seed production from weeds that are missed by herbicide application can affect future weed populations and management decisions. It may be possible to expand the utility of computerized weed management decision aids to include an estimate of weed seed production resulting from selected treatments based on crop yield potential. Field studies were conducted in soybean near Columbia, MO, to determine whether weed control recommendations based on crop yield potential from a computerized weed management decision aid influence weed seed production in two soybean row spacings. At approximately 28 d after planting, weed densities and heights were entered into WeedSOFT®to generate a list of treatments ranked by predicted crop yields. Treatments included: (1) highest predicted crop yield in a glyphosate-resistant system, (2) highest predicted crop yield in a nonglyphosate-resistant system, (3) a 10% yield reduction, (4) a 20% yield reduction, and (5) an untreated control. These treatments were applied to soybean grown in 38- and 76-cm rows. Treatments that provided 90% or higher control of an individual species at 22 d after treatment usually produced less seed than untreated checks. Weed seed production based on early-season herbicide efficacy showed a linear relationship and was relatively predictable (r2≥ 0.52) for the predominant weed species. For less dominant weed species, weed seed production was not strongly correlated (r2≤ 0.27) to early-season herbicide efficacy but apparently influenced by control of other weed species. Narrow row spacing reduced giant foxtail biomass both years but did not reduce common ragweed and ivyleaf morningglory biomass. Narrow rows did not decrease giant foxtail, common ragweed, and ivyleaf morningglory seed production.

Responses of Rice Flatsedge (Cyperus iria) and Barnyardgrass (Echinochloa crus-galli) to Rice Interference

Weed Science ◽  
2010 ◽  
Vol 58 (3) ◽  
pp. 204-208 ◽  
Author(s):  
Bhagirath S. Chauhan ◽  
David E. Johnson
Keyword(s):  
Weed Management ◽  
Management Practices ◽  
Stem Elongation ◽  
Weight Ratio ◽  
Stem Length ◽  
Integrated Weed Management ◽  
Shoot Biomass ◽  
Weed Species ◽  
Complete Control ◽  
Crop Density

Rice flatsedge and barnyardgrass are widespread and competitive weeds in direct-seeded rice. Developing integrated weed management strategies that elevate suppression of weeds by rice through crop density, nutrition, and cultivar choice requires better understanding of the extent to which rice interferes with the growth of these weeds and how these species respond to resource limitation with crop interference. Rice interference reduced the height of barnyardgrass but did not affect height of rice flatsedge. These weed species were able to grow taller than rice and thus avoided being shaded. Increased specific stem length under crop interference may demonstrate a strategy of stem elongation to allow the top portion of the weeds to be kept out of shade. Rice interference reduced inflorescence and shoot biomass of both weed species. Barnyardgrass showed the ability to reduce the effects of rice interference by increasing leaf weight ratio. The present study shows that crop interference alone may reduce weed growth but may not give complete control of these weed species. This highlights the need for the integration of management practices to achieve control of these weed species.

Bio-efficacy of post emergence herbicides in boro rice nursery as well as main field and their residual effects on non-target microorganisms

2020 ◽  
Vol 57 (3) ◽  
pp. 199-210
Author(s):  
Rajib Kundu ◽  
Mousumi Mondal ◽  
Sourav Garai ◽  
Ramyajit Mondal ◽  
Ratneswar Poddar
Keyword(s):  
Weed Control ◽  
Weed Management ◽  
Field Experiments ◽  
Block Design ◽  
Resistance Index ◽  
Residual Effects ◽  
Cost Ratio ◽  
Main Field ◽  
Weed Species ◽  
Similar Treatment

Field experiments were conducted at research farm of Bidhan Chandra Krishi Viswavidyalaya, Kalyani, West Bengal, India (22°97' N latitude and 88°44' E longitude, 9.75 m above mean sea level) under natural weed infestations in boro season rice (nursery bed as well as main field) during 2017-18 and 2018-19 to evaluate the herbicidal effects on weed floras, yield, non-target soil organisms to optimize the herbicide use for sustainable rice-production. Seven weed control treatments including three doses of bispyribac-sodium 10% SC (150,200, and 250 ml ha-1), two doses of fenoxaprop-p-ethyl 9.3% EC (500 and 625 ml ha-1), one weed free and weedy check were laid out in a randomized complete block design, replicated thrice. Among the tested herbicides, bispyribac-sodium with its highest dose (250 ml ha-1) resulted in maximum weed control efficiency, treatment efficiency index and crop resistance index irrespective of weed species and dates of observation in both nursery as well as main field. Similar treatment also revealed maximum grain yield (5.20 t ha-1), which was 38.38% higher than control, closely followed by Fenoxaprop-p-ethyl (625 ml ha-1) had high efficacy against grasses, sedge and broadleaf weed flora. Maximum net return (Rs. 48765 ha-1) and benefit cost ratio (1.72) were obtained from the treatment which received bispyribac-sodium @ 250 ml ha-1. Based on overall performance, the bispyribac-sodium (250 ml ha-1) may be considered as the best herbicide treatment for weed management in transplanted rice as well as nursery bed.

scholarly journals Weeds Hosting the Soybean Cyst Nematode (Heterodera glycines Ichinohe): Management Implications in Agroecological Systems

Agronomy ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 146
Author(s):  
Leonardo F. Rocha ◽  
Karla L. Gage ◽  
Mirian F. Pimentel ◽  
Jason P. Bond ◽  
Ahmad M. Fakhoury
Keyword(s):  
Weed Management ◽  
Soybean Cyst Nematode ◽  
Heterodera Glycines ◽  
Integrated Management ◽  
Cropping System ◽  
Cyst Nematode ◽  
Weed Species ◽  
Initial Inoculum ◽  
Herbicide Resistant ◽  
Sites Of Action

The soybean cyst nematode (SCN; Heterodera glycines Ichinohe) is a major soybean-yield-limiting soil-borne pathogen, especially in the Midwestern US. Weed management is recommended for SCN integrated management, since some weed species have been reported to be hosts for SCN. The increase in the occurrence of resistance to herbicides complicates weed management and may further direct ecological–evolutionary (eco–evo) feedbacks in plant–pathogen complexes, including interactions between host plants and SCN. In this review, we summarize weed species reported to be hosts of SCN in the US and outline potential weed–SCN management interactions. Plants from 23 families have been reported to host SCN, with Fabaceae including most host species. Out of 116 weeds hosts, 14 species have known herbicide-resistant biotypes to 8 herbicide sites of action. Factors influencing the ability of weeds to host SCN are environmental and edaphic conditions, SCN initial inoculum, weed population levels, and variations in susceptibility of weed biotypes to SCN within a population. The association of SCN on weeds with relatively little fitness cost incurred by the latter may decrease the competitive ability of the crop and increase weed reproduction when SCN is present, feeding back into the probability of selecting for herbicide-resistant weed biotypes. Therefore, proper management of weed hosts of SCN should be a focus of integrated pest management (IPM) strategies to prevent further eco–evo feedbacks in the cropping system.

scholarly journals Glyphosate Resistance in Perennial Ryegrass (Lolium perenneL.) is Associated with a Fitness Penalty

Weed Science ◽  
2016 ◽  
Vol 64 (1) ◽  
pp. 71-79 ◽  
Author(s):  
Marcos Yanniccari ◽  
Martín Vila-Aiub ◽  
Carolina Istilart ◽  
Horacio Acciaresi ◽  
Ana M. Castro
Keyword(s):  
Perennial Ryegrass ◽  
Water Availability ◽  
Field Experiments ◽  
Seed Mass ◽  
Selection Effect ◽  
Glyphosate Resistance ◽  
Shoot Biomass ◽  
Seed Number ◽  
Fitness Costs ◽  
Weed Species

The net selection effect of herbicides on herbicide-resistance traits in weeds is conditioned by the fitness benefits and costs associated with resistance alleles. Fitness costs play an important evolutionary role preventing the fixation of adaptive alleles and contributing to the maintenance of genetic polymorphisms within populations. Glyphosate is widely used in world agriculture, which has led to the evolution of widespread glyphosate resistance in many weed species. The fitness of glyphosate-resistant and -susceptible perennial ryegrass plants selected from within a single population were studied in two field experiments conducted during 2011 and 2012 under different soil water availability. Glyphosate-resistant plants showed a reduction in height of 12 and 16%, leaf blade area of 16 and 33%, shoot biomass of 45 and 55%, seed number of 33 and 53%, and total seed mass of 16 and 5% compared to glyphosate-susceptible plants in 2011 and 2012, respectively. The reduction in seed number per plant resulted in a 40% fitness cost associated with the glyphosate-resistance trait in perennial ryegrass. Fitness costs of glyphosate-resistant plants were expressed under both conditions of water availability. These results could be useful for designing management strategies and exploiting the reduced glyphosate-resistant perennial ryegrass fitness in the absence of glyphosate selection.

scholarly journals Morphological and Metabolite Responses of Potatoes under Various Phosphorus Levels and Their Amelioration by Plant Growth-Promoting Rhizobacteria

2021 ◽  
Vol 22 (10) ◽  
pp. 5162
Author(s):  
Leangsrun Chea ◽  
Birgit Pfeiffer ◽  
Dominik Schneider ◽  
Rolf Daniel ◽  
Elke Pawelzik ◽  
...  
Keyword(s):  
Amino Acids ◽  
Plant Growth ◽  
Plant Growth Promoting Rhizobacteria ◽  
Shoot Biomass ◽  
Root Surface Area ◽  
Limiting Factor ◽  
P Availability ◽  
P Deficiency ◽  
Plant Growth Promoting ◽  
Growth Promoting

Low phosphorus (P) availability is a major limiting factor for potatoes. P fertilizer is applied to enhance P availability; however, it may become toxic when plants accumulate at high concentrations. Therefore, it is necessary to gain more knowledge of the morphological and biochemical processes associated with P deficiency and toxicity for potatoes, as well as to explore an alternative approach to ameliorate the P deficiency condition. A comprehensive study was conducted (I) to assess plant morphology, mineral allocation, and metabolites of potatoes in response to P deficiency and toxicity; and (II) to evaluate the potency of plant growth-promoting rhizobacteria (PGPR) in improving plant biomass, P uptake, and metabolites at low P levels. The results revealed a reduction in plant height and biomass 60–80% under P deficiency compared to P optimum. P deficiency and toxicity conditions also altered the mineral concentration and allocation in plants due to nutrient imbalance. The stress induced by both P deficiency and toxicity was evident from an accumulation of proline and total free amino acids in young leaves and roots. Furthermore, root metabolite profiling revealed that P deficiency reduced sugars by 50–80% and organic acids by 20–90%, but increased amino acids by 1.5–14.8 times. However, the effect of P toxicity on metabolic changes in roots was less pronounced. Under P deficiency, PGPR significantly improved the root and shoot biomass, total root length, and root surface area by 32–45%. This finding suggests the potency of PGPR inoculation to increase potato plant tolerance under P deficiency.

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