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Potential effectiveness of harvest weed seed control (HWSC) systems depends upon seed shatter of the target weed species at crop maturity, enabling its collection and processing at crop harvest. However, seed retention likely is influenced by agroecological and environmental factors. In 2016 and 2017, we assessed seed-shatter phenology in 13 economically important broadleaf weed species in soybean [Glycine max (L.) Merr.] from crop physiological maturity to 4 wk after physiological maturity at multiple sites spread across 14 states in the southern, northern, and mid-Atlantic United States. Greater proportions of seeds were retained by weeds in southern latitudes and shatter rate increased at northern latitudes. Amaranthus spp. seed shatter was low (0% to 2%), whereas shatter varied widely in common ragweed (Ambrosia artemisiifolia L.) (2% to 90%) over the weeks following soybean physiological maturity. Overall, the broadleaf species studied shattered less than 10% of their seeds by soybean harvest. Our results suggest that some of the broadleaf species with greater seed retention rates in the weeks following soybean physiological maturity may be good candidates for HWSC.
Lauren M. Schwartz-Lazaro; Lovreet S. Shergill; Jeffrey A. Evans; Muthukumar V. Bagavathiannan; Shawn C. Beam; Mandy D. Bish; Jason A. Bond; Kevin W. Bradley; William S. Curran; Adam S. Davis; Wesley J. Everman; Michael L. Flessner; Steven C. Harring; Nicholas R. Jordan; Nicholas E. Korres; John L. Lindquist; Jason K. Norsworthy; Tameka L. Sanders; Larry E. Steckel; Mark J. VanGessel; Blake Young; Steven B. Mirsky. Seed-shattering phenology at soybean harvest of economically important weeds in multiple regions of the United States. Part 1: Broadleaf species. Weed Science 2020, 69, 95 -103.
AMA StyleLauren M. Schwartz-Lazaro, Lovreet S. Shergill, Jeffrey A. Evans, Muthukumar V. Bagavathiannan, Shawn C. Beam, Mandy D. Bish, Jason A. Bond, Kevin W. Bradley, William S. Curran, Adam S. Davis, Wesley J. Everman, Michael L. Flessner, Steven C. Harring, Nicholas R. Jordan, Nicholas E. Korres, John L. Lindquist, Jason K. Norsworthy, Tameka L. Sanders, Larry E. Steckel, Mark J. VanGessel, Blake Young, Steven B. Mirsky. Seed-shattering phenology at soybean harvest of economically important weeds in multiple regions of the United States. Part 1: Broadleaf species. Weed Science. 2020; 69 (1):95-103.
Chicago/Turabian StyleLauren M. Schwartz-Lazaro; Lovreet S. Shergill; Jeffrey A. Evans; Muthukumar V. Bagavathiannan; Shawn C. Beam; Mandy D. Bish; Jason A. Bond; Kevin W. Bradley; William S. Curran; Adam S. Davis; Wesley J. Everman; Michael L. Flessner; Steven C. Harring; Nicholas R. Jordan; Nicholas E. Korres; John L. Lindquist; Jason K. Norsworthy; Tameka L. Sanders; Larry E. Steckel; Mark J. VanGessel; Blake Young; Steven B. Mirsky. 2020. "Seed-shattering phenology at soybean harvest of economically important weeds in multiple regions of the United States. Part 1: Broadleaf species." Weed Science 69, no. 1: 95-103.
The utilization and management of agricultural wastes for plant growth and fertilization or crop production and protection purposes can facilitate the transition of current agricultural systems or “productivism agriculture” to a post-productivism agriculture or “production of nature” era. The availability of agricultural wastes, a theoretical estimation indicates that approximately 3.5–17.0 billion tons of agricultural wastes can be produced worldwide, in combination with the various technologies for the conversion of these wastes to bioenergy are significant factors that enhance the value of this type of feedstock. In addition, the role of agricultural wastes as mean for weed control (e.g. maize gluten meal, Brassicaceae seed meal, abrasive grit), soil amendments and fertilizer substitute (e.g. abrasive grit, biochar, Brassicaceae oilseed meal, digestate from anaerobic digestion), or plant growing medium (e.g. composts) signifies the added value of these materials toward sustainable production systems. Nevertheless, the utilization of agricultural wastes should not disturb the soil carbon and other nutrients dynamics. This can be avoided by setting appropriate limits and continued monitoring, hence, reducing uncertainty about their beneficial environmental performance.
Nicholas E. Korres. Utilization and Management of Agricultural Wastes for Bioenergy Production, Weed Control, and Soil Improvement Through Microbial and Technical Processes. Environmental Microbiology and Biotechnology 2020, 143 -173.
AMA StyleNicholas E. Korres. Utilization and Management of Agricultural Wastes for Bioenergy Production, Weed Control, and Soil Improvement Through Microbial and Technical Processes. Environmental Microbiology and Biotechnology. 2020; ():143-173.
Chicago/Turabian StyleNicholas E. Korres. 2020. "Utilization and Management of Agricultural Wastes for Bioenergy Production, Weed Control, and Soil Improvement Through Microbial and Technical Processes." Environmental Microbiology and Biotechnology , no. : 143-173.
Nicholas E. Korres; Nicholas Hausman; James L. Moody; Yasin E. Kitis; Martin Williams. Integrated weed management strategies with cereal rye mulch in processing vegetable legumes. Agronomy Journal 2020, 112, 4264 -4275.
AMA StyleNicholas E. Korres, Nicholas Hausman, James L. Moody, Yasin E. Kitis, Martin Williams. Integrated weed management strategies with cereal rye mulch in processing vegetable legumes. Agronomy Journal. 2020; 112 (5):4264-4275.
Chicago/Turabian StyleNicholas E. Korres; Nicholas Hausman; James L. Moody; Yasin E. Kitis; Martin Williams. 2020. "Integrated weed management strategies with cereal rye mulch in processing vegetable legumes." Agronomy Journal 112, no. 5: 4264-4275.
Knowledge of crop–weed interference effects on weed biology along with yield penalties can be used for the development of integrated weed management (IWM) tactics. Nevertheless, little is known about the beneficial effects of soybean [Glycine max (L.) Merr.] density, an important aspect of IWM, on late Palmer amaranth (Amaranthus palmeri S. Watson) establishment time. Two field experiments were conducted in 2014 and 2015 to investigate how various soybean densities and A. palmeri establishment timings in weeks after crop emergence (WAE) affect height, biomass, and seed production of the weed but also crop yield in drill-seeded soybean. Soybean density had a significant impact on dry weight and seed production of A. palmeri that established within the first 2 wk of crop emergence, but not for establishment timings of the weed 4 wk and later in relation to crop emergence. Differential performance of A. palmeri gender was observed, regarding greater biomass production of female than male plants under crop presence, and merits further investigation. Grain yield reductions were recorded at earlier A. palmeri establishment timings (i.e., 0 and 1 WAE) compared with 8 WAE establishment timing in 2014 and 2015. High soybean densities resulted in greater soybean yields compared with low soybean density, but no grain yield benefits were observed between medium and high soybean densities. Crop budget analysis revealed the benefits of moderate seeding rate (i.e., 250, 000 seeds ha−1) increases in comparison to lower (i.e., 125,000 seeds ha−1) or high (i.e., 400,000 seeds ha−1) on crop revenue, net income returns, and breakeven price. Earlier A. palmeri establishment timings (i.e., 0, 1, and 2 WAE) resulted in lower crop revenue and net income returns compared with later establishment timings of the weed.
Nicholas E. Korres; Jason K. Norsworthy; Andy Mauromoustakos; Martin Williams. Soybean density and Palmer amaranth (Amaranthus palmeri) establishment time: effects on weed biology, crop yield, and economic returns. Weed Science 2020, 68, 467 -475.
AMA StyleNicholas E. Korres, Jason K. Norsworthy, Andy Mauromoustakos, Martin Williams. Soybean density and Palmer amaranth (Amaranthus palmeri) establishment time: effects on weed biology, crop yield, and economic returns. Weed Science. 2020; 68 (5):467-475.
Chicago/Turabian StyleNicholas E. Korres; Jason K. Norsworthy; Andy Mauromoustakos; Martin Williams. 2020. "Soybean density and Palmer amaranth (Amaranthus palmeri) establishment time: effects on weed biology, crop yield, and economic returns." Weed Science 68, no. 5: 467-475.
Modernization in the crop cultivation and development of high yielding varieties resulted in increased crop residues. A large portion of crop residues is not handled appropriately, which leads to environmental burden on society. The crop residues are rich in organic substances, which can be better utilized for various purposes, including energy generation. The utilization of crop residues for energy generation has partially contributed to resolve the inappropriate handling practices, thus reducing their environmental impacts. Life cycle assessment (LCA) is used as a tool to investigate environmental sustainability and can be explored to integrate with social and economic effects to quantify environmental impacts for energy generation from crop residues. This review will provide a comprehensive understanding on LCA inference for decision support to policy-makers and different relevant choices to various applications for sustainable energy generation from crop residues.
Shiv Prasad; Anoop Singh; Nicholas E. Korres; Dheeraj Rathore; Surajbhan Sevda; Deepak Pant. Sustainable utilization of crop residues for energy generation: A life cycle assessment (LCA) perspective. Bioresource Technology 2020, 303, 122964 .
AMA StyleShiv Prasad, Anoop Singh, Nicholas E. Korres, Dheeraj Rathore, Surajbhan Sevda, Deepak Pant. Sustainable utilization of crop residues for energy generation: A life cycle assessment (LCA) perspective. Bioresource Technology. 2020; 303 ():122964.
Chicago/Turabian StyleShiv Prasad; Anoop Singh; Nicholas E. Korres; Dheeraj Rathore; Surajbhan Sevda; Deepak Pant. 2020. "Sustainable utilization of crop residues for energy generation: A life cycle assessment (LCA) perspective." Bioresource Technology 303, no. : 122964.
The increased availability and high adoption rate of glyphosate-tolerant crops have selected for several glyphosate-resistant weed species. The response of representative weed species to glyphosate was assessed to provide insights and tools for optimizing glyphosate use for economic, agronomic and environmental reasons. Anoda cristata, Chenopodium album, Digitaria sanguinalis, Eleusine indica and Portulaca oleracea were grown outdoors in pots containing commercial potting medium. An increasing dose of glyphosate was applied to these species at three growth stages. Weed response was evaluated visually compared to the nontreated control and shoot dry weights were recorded. Fecundity was also determined. Based on visual evaluations, the dose of glyphosate required to attain 90% control of the species tested exhibited an application rate margin up to 28.5-fold compared to recommended rate, denoting a potential for rate optimization. Except for A. cristata, the recommended dose of glyphosate could be reduced by 30%–60% and still achieve 90% or greater control. The order of species sensitivity, based on effective dose 50 (ED50 )values, was E. indica > C. album > D. sanguinalis > P. oleracea > A. cristata. The ratio of ED90/ED50 was constant, indicating that increasing the glyphosate dose 8.7-fold would reduce weed biomass 1.8-fold. In most cases, the fecundity-avoidance biomass threshold (i.e., the maximum allowable weed biomass for herbicide application in order to prevent weed seed production and dispersal) for glyphosate was below the ED90 value. Complimentary measures such as fecundity-avoidance biomass threshold will improve herbicide evaluation procedures and preserve the effectiveness of herbicides, including glyphosate, on sensitive species, an important issue particularly when action to reduce herbicide resistance development is highly required.
Eduardo S Leguizamon; German Ferrari; Martin M Williams Ii; Nilda R Burgos; Ilias Travlos; Nicholas Korres. Response of Annual Weeds to Glyphosate: Evaluation and Optimization of Application Rate Based on Fecundity-Avoidance Biomass Threshold Criterion. Agronomy 2019, 9, 851 .
AMA StyleEduardo S Leguizamon, German Ferrari, Martin M Williams Ii, Nilda R Burgos, Ilias Travlos, Nicholas Korres. Response of Annual Weeds to Glyphosate: Evaluation and Optimization of Application Rate Based on Fecundity-Avoidance Biomass Threshold Criterion. Agronomy. 2019; 9 (12):851.
Chicago/Turabian StyleEduardo S Leguizamon; German Ferrari; Martin M Williams Ii; Nilda R Burgos; Ilias Travlos; Nicholas Korres. 2019. "Response of Annual Weeds to Glyphosate: Evaluation and Optimization of Application Rate Based on Fecundity-Avoidance Biomass Threshold Criterion." Agronomy 9, no. 12: 851.
Palmer amaranth is one of the most problematic weeds in cropping systems of North America, especially in midsouthern United States, because of its competitive ability and propensity to evolve resistance to several herbicide sites of action. Previously, we confirmed and characterized the first case of nontarget site resistance (NTSR) to fomesafen in a Palmer amaranth accession from Randolph County, AR (RCA). The primary basis of the present study was to evaluate the cross- and multiple-resistance profile of the RCA accession. The fomesafen dose-response assay in the presence of malathion revealed a lower level of RCA resistance when compared with fomesafen alone. The resistance index of the RCA accession, based on 50% biomass reduction, ranged from 63-fold (fomesafen alone) to 22-fold (malathion plus fomesafen), when compared with a 2007 susceptible, and 476-fold and 167-fold, respectively, relative to a 1986 susceptible check. The RCA accession was resistant to other protoporphyrinogen oxidase (PPO) inhibitors (i.e., flumioxazin, acifluorfen, saflufenacil) as well as the 4-hydroxyphenylpyruvate dioxygenase (HPPD) inhibitor tembotrione and acetolactate synthase (ALS) inhibitor pyrithiobac sodium. Sequencing of theALSgene revealed no point mutations, indicating that a target-site mechanism is not involved in conferring ALS-inhibitor resistance in the RCA accession. Of the three PPO-inhibiting herbicides tested in combination with the malathion, saflufenacil resulted in the greatest biomass reduction (80%;P< 0.05) and lowest survival rate (23%;P< 0.05) relative to nontreated plants. The application of cytochrome P450 or glutathioneS-transferase inhibitors with fomesafen did not lead to any adverse effects on soybean, suggesting a possible role for these compounds for management of NTSR under field conditions. These results shed light on the relative unpredictability of NTSR in conferring herbicide cross- and multiple resistance in Palmer amaranth.
Vijay K. Varanasi; Chad Brabham; Nicholas E. Korres; Jason K. Norsworthy. Nontarget site resistance in Palmer amaranth [Amaranthus palmeri(S.) Wats.] confers cross-resistance to protoporphyrinogen oxidase-inhibiting herbicides. Weed Technology 2019, 33, 349 -354.
AMA StyleVijay K. Varanasi, Chad Brabham, Nicholas E. Korres, Jason K. Norsworthy. Nontarget site resistance in Palmer amaranth [Amaranthus palmeri(S.) Wats.] confers cross-resistance to protoporphyrinogen oxidase-inhibiting herbicides. Weed Technology. 2019; 33 (2):349-354.
Chicago/Turabian StyleVijay K. Varanasi; Chad Brabham; Nicholas E. Korres; Jason K. Norsworthy. 2019. "Nontarget site resistance in Palmer amaranth [Amaranthus palmeri(S.) Wats.] confers cross-resistance to protoporphyrinogen oxidase-inhibiting herbicides." Weed Technology 33, no. 2: 349-354.
Weed science, as an integral part of agricultural production needs to evolve by moving away from its mono-disciplinary perspective at targeting weeds, sometimes a single species, through the overreliance on few single herbicide mechanisms of action. Herbicides remain a simple and cost-effective way to control weeds but they are rapidly losing their effectiveness due to evolution of herbicide resistance. Additionally, weed science has been left wanting for a strong theoretical foundation rooted in evolutionary and ecological disciplines therefore, there is a great need for a new weed management paradigm in modern agriculture based on ecological principles and nonconventional weed management approaches. The “many little hammers” concept and the “use of technological advancement” are two major integrated weed management components that are gaining momentum. Automated, robotic weed control is being rapidly developed, particularly for vegetable crops and organic agriculture. Cover crops and weed seed destruction techniques are becoming popular with growers. In the future, RNAi technology, gene editing and robotics will yield new tools for weed control. Agriculture is also moving into a new era of big data or “digital farming.” It will be interesting to see what new, unforeseen weed control solutions will be derived from this new farming approach that will allow more intelligent application and integration of weed management technologies. In an attempt to facilitate the suitability of these technologies into integrated weed management systems, this chapter reviews the strengths and weaknesses of these modern technologies and tools, and it highlights future research needs for each of these technologies.
Nicholas E. Korres; Nilda R. Burgos; Ilias Travlos; Maurizio Vurro; Thomas K. Gitsopoulos; Vijaya K. Varanasi; Stephen O. Duke; Per Kudsk; Chad Brabham; Christopher E. Rouse; Reiofeli Salas-Perez. New directions for integrated weed management: Modern technologies, tools and knowledge discovery. Advances in Agronomy 2019, 243 -319.
AMA StyleNicholas E. Korres, Nilda R. Burgos, Ilias Travlos, Maurizio Vurro, Thomas K. Gitsopoulos, Vijaya K. Varanasi, Stephen O. Duke, Per Kudsk, Chad Brabham, Christopher E. Rouse, Reiofeli Salas-Perez. New directions for integrated weed management: Modern technologies, tools and knowledge discovery. Advances in Agronomy. 2019; ():243-319.
Chicago/Turabian StyleNicholas E. Korres; Nilda R. Burgos; Ilias Travlos; Maurizio Vurro; Thomas K. Gitsopoulos; Vijaya K. Varanasi; Stephen O. Duke; Per Kudsk; Chad Brabham; Christopher E. Rouse; Reiofeli Salas-Perez. 2019. "New directions for integrated weed management: Modern technologies, tools and knowledge discovery." Advances in Agronomy , no. : 243-319.
Information about weed biology and weed population dynamics is critical for the development of efficient weed management programs. A field experiment was conducted in Fayetteville, AR, during 2014 and 2015 to examine the effects of Palmer amaranth (Amaranthus palmeriS. Watson) establishment time in relation to soybean [Glycine max(L.) Merr.] emergence and the effects ofA. palmeridistance from the soybean row on the weed’s height, biomass, seed production, and flowering time and on soybean yield. The establishment time factor, in weeks after crop emergence (WAE), was composed of six treatment levels (0, 1, 2, 4, 6, and 8 WAE), whereas the distance from the crop consisted of three treatment levels (0, 24, and 48 cm). Differences inA. palmeribiomass and seed production averaged across distance from the crop were found at 0 and 1 WAE in both years. Establishment time had a significant effect onA. palmeriseed production through greater biomass production and height increases at earlier dates.Amaranthus palmerithat was established with the crop (0 WAE) overtopped soybean at about 7 and 10 WAE in 2014 and 2015, respectively. Distance from the crop affectedA. palmeriheight, biomass, and seed production. The greater the distance from the crop, the higherA. palmeriheight, biomass, and seed production at 0 and 1 WAE compared with other dates (i.e., 2, 4, 6, and 8 WAE).Amaranthus palmeriestablishment time had a significant impact on soybean yield, but distance from the crop did not. The earlierA. palmeriinterfered with soybean (0 and 1 WAE), the greater the crop yield reduction; after that period no significant yield reductions were recorded compared with the rest of the weed establishment times. Knowledge ofA. palmeriresponse, especially at early stages of its life cycle, is important for designing efficient weed management strategies and cropping systems that can enhance crop competitiveness. Control ofA. palmeriwithin the first week after crop emergence or reduced distance between crop and weed are important factors for an effective implementation of weed management measures againstA. palmeriand reduced soybean yield losses due to weed interference.
Nicholas E. Korres; Jason K. Norsworthy; Andy Mauromoustakos. Effects of Palmer Amaranth (Amaranthus palmeri) Establishment Time and Distance from the Crop Row on Biological and Phenological Characteristics of the Weed: Implications on Soybean Yield. Weed Science 2019, 67, 126 -135.
AMA StyleNicholas E. Korres, Jason K. Norsworthy, Andy Mauromoustakos. Effects of Palmer Amaranth (Amaranthus palmeri) Establishment Time and Distance from the Crop Row on Biological and Phenological Characteristics of the Weed: Implications on Soybean Yield. Weed Science. 2019; 67 (1):126-135.
Chicago/Turabian StyleNicholas E. Korres; Jason K. Norsworthy; Andy Mauromoustakos. 2019. "Effects of Palmer Amaranth (Amaranthus palmeri) Establishment Time and Distance from the Crop Row on Biological and Phenological Characteristics of the Weed: Implications on Soybean Yield." Weed Science 67, no. 1: 126-135.
Cover crops are being increasingly recommended as an integrated approach to controlling glyphosate-resistant Palmer amaranth and other troublesome weeds. Thus, a field experiment was conducted in 2010 through 2012 to evaluate the critical period for weed control (CPWC) in cotton as affected by a cereal rye cover crop and tillage. The management systems evaluated included conventional tillage following winter fallow, conservation tillage (CT) following winter fallow, and CT following a cereal rye cover crop managed for maximum biomass. Throughout most of the growing season, weed biomass in cereal rye cover crop plots was less than the CT winter-fallow system in both years and less than both CT winter fallow and conventional tillage in 2012. The CPWC was shortest in 2010 following conventional tillage; however, in 2012, production system influences on CPWC were less. The presence of the rye cover crop delayed the critical timing for weed removal (CTWR) approximately 8 d compared with fallow treatment both years, while conventional tillage delayed CTWR about 2 wk compared with winter fallow. Relative yield losses in both years did not reach the 5% threshold limit until about 2 wk after planting (WAP) for CT following winter fallow, 3 WAP for CT following a cover crop, and 3.5 WAP following conventional tillage. Thus, CT following winter fallow should be avoided to minimize cotton yield loss.
Andrew J. Price; Nicholas E. Korres; Jason K. Norsworthy; Steve Li. Influence of a Cereal Rye Cover Crop and Conservation Tillage on the Critical Period for Weed Control in Cotton. Weed Technology 2018, 32, 683 -690.
AMA StyleAndrew J. Price, Nicholas E. Korres, Jason K. Norsworthy, Steve Li. Influence of a Cereal Rye Cover Crop and Conservation Tillage on the Critical Period for Weed Control in Cotton. Weed Technology. 2018; 32 (6):683-690.
Chicago/Turabian StyleAndrew J. Price; Nicholas E. Korres; Jason K. Norsworthy; Steve Li. 2018. "Influence of a Cereal Rye Cover Crop and Conservation Tillage on the Critical Period for Weed Control in Cotton." Weed Technology 32, no. 6: 683-690.
Resistance to herbicides in Italian ryegrass (Lolium perenne L. ssp. multiflorum (Lam.) Husnot) is an economically important herbicide-resistance issue in world agriculture. Diclofop-resistant ryegrass is the number one weed problem in Arkansas wheat. Field studies were conducted from 2006 through 2008 at Bredlow corner and Fayetteville, Arkansas, USA to determine the effect of herbicide programs consisting of pinoxaden (Axial) alone or in mixtures with preemergence and postemergence herbicides, along with tillage systems, for managing diclofop-resistant Italian ryegrass. Italian ryegrass control, wheat injury, and grain yield were evaluated. A single treatment with pinoxaden alone resulted in 58% ryegrass control and 1488 kg ha−1 grain yield. The best treatment was metribuzin followed by mesosulfuron, which resulted in 2793 kg grain yield ha−1, a 47% increase compared to pinoxaden alone. In Fayetteville (2006–2007 and 2007–2008), the best treatment was two applications of metribuzin, which yielded about 3700 kg grain ha−1. A single application of pinoxaden resulted in 40% loss of grain yield compared to a single application of flufenacet + metribuzin and almost 50% yield loss compared to sequential application of metribuzin. Yield loss was attributed due to insufficient control of Italian ryegrass. The effect of tillage on Italian ryegrass was inconsistent between years and treatments. In the first year, for example, tillage × herbicide treatments did not differ. In the second and third year, control of Italian ryegrass was better in no-till than in conventional till in both locations. In conclusion, pinoxaden alone could not control diclofop-resistant Italian ryegrass sufficiently. Other herbicide modes of action need to be added to the management program of diclofop-resistant Italian ryegrass, especially one with residual activity such as metribuzin.
Taghi Bararpour; Nicholas E. Korres; Nilda R. Burgos; Ralph R. Hale; Te-Ming Paul Tseng. Performance of Pinoxaden on the Control of Diclofop-Resistant Italian Ryegrass (Lolium perenne L. ssp. multiflorum) in Winter Wheat. Agriculture 2018, 8, 114 .
AMA StyleTaghi Bararpour, Nicholas E. Korres, Nilda R. Burgos, Ralph R. Hale, Te-Ming Paul Tseng. Performance of Pinoxaden on the Control of Diclofop-Resistant Italian Ryegrass (Lolium perenne L. ssp. multiflorum) in Winter Wheat. Agriculture. 2018; 8 (7):114.
Chicago/Turabian StyleTaghi Bararpour; Nicholas E. Korres; Nilda R. Burgos; Ralph R. Hale; Te-Ming Paul Tseng. 2018. "Performance of Pinoxaden on the Control of Diclofop-Resistant Italian Ryegrass (Lolium perenne L. ssp. multiflorum) in Winter Wheat." Agriculture 8, no. 7: 114.
Knowledge of the effects of burial depth and burial duration on seed viability and, consequently, seedbank persistence of Palmer amaranth (Amaranthus palmeriS. Watson) and waterhemp [Amaranthus tuberculatus(Moq.) J. D. Sauer] ecotypes can be used for the development of efficient weed management programs. This is of particular interest, given the great fecundity of both species and, consequently, their high seedbank replenishment potential. Seeds of both species collected from five different locations across the United States were investigated in seven states (sites) with different soil and climatic conditions. Seeds were placed at two depths (0 and 15 cm) for 3 yr. Each year, seeds were retrieved, and seed damage (shrunken, malformed, or broken) plus losses (deteriorated and futile germination) and viability were evaluated. Greater seed damage plus loss averaged across seed origin, burial depth, and year was recorded for lots tested at Illinois (51.3% and 51.8%) followed by Tennessee (40.5% and 45.1%) and Missouri (39.2% and 42%) forA. palmeriandA. tuberculatus, respectively. The site differences for seed persistence were probably due to higher volumetric water content at these sites. Rates of seed demise were directly proportional to burial depth (α=0.001), whereas the percentage of viable seeds recovered after 36 mo on the soil surface ranged from 4.1% to 4.3% compared with 5% to 5.3% at the 15-cm depth forA. palmeriandA. tuberculatus, respectively. Seed viability loss was greater in the seeds placed on the soil surface compared with the buried seeds. The greatest influences on seed viability were burial conditions and time and site-specific soil conditions, more so than geographical location. Thus, management of these weed species should focus on reducing seed shattering, enhancing seed removal from the soil surface, or adjusting tillage systems.
Nicholas E. Korres; Jason Norsworthy; Bryan G. Young; Daniel B. Reynolds; William Johnson; Shawn Conley; Reid J. Smeda; Thomas C. Mueller; Douglas J. Spaunhorst; Karla L. Gage; Mark Loux; Greg R. Kruger; Muthukumar V. Bagavathiannan. Seedbank Persistence of Palmer Amaranth (Amaranthus palmeri) and Waterhemp (Amaranthus tuberculatus) across Diverse Geographical Regions in the United States. Weed Science 2018, 66, 446 -456.
AMA StyleNicholas E. Korres, Jason Norsworthy, Bryan G. Young, Daniel B. Reynolds, William Johnson, Shawn Conley, Reid J. Smeda, Thomas C. Mueller, Douglas J. Spaunhorst, Karla L. Gage, Mark Loux, Greg R. Kruger, Muthukumar V. Bagavathiannan. Seedbank Persistence of Palmer Amaranth (Amaranthus palmeri) and Waterhemp (Amaranthus tuberculatus) across Diverse Geographical Regions in the United States. Weed Science. 2018; 66 (4):446-456.
Chicago/Turabian StyleNicholas E. Korres; Jason Norsworthy; Bryan G. Young; Daniel B. Reynolds; William Johnson; Shawn Conley; Reid J. Smeda; Thomas C. Mueller; Douglas J. Spaunhorst; Karla L. Gage; Mark Loux; Greg R. Kruger; Muthukumar V. Bagavathiannan. 2018. "Seedbank Persistence of Palmer Amaranth (Amaranthus palmeri) and Waterhemp (Amaranthus tuberculatus) across Diverse Geographical Regions in the United States." Weed Science 66, no. 4: 446-456.
There is great value in quantifying and reporting weed seed production as a component of herbicide efficacy evaluations for two reasons. First, visual weed control ratings and associated measurements such as weed density and biomass are not sufficient indicators of fecundity. Second, knowledge of fecundity associated with herbicide treatments can guide the development of effective management programs that impact long-term weed population dynamics and reduce the risk of herbicide resistance.
Jason Norsworthy; Nicholas E. Korres; Muthukumar V. Bagavathiannan. Weed Seedbank Management: Revisiting How Herbicides Are Evaluated. Weed Science 2018, 66, 415 -417.
AMA StyleJason Norsworthy, Nicholas E. Korres, Muthukumar V. Bagavathiannan. Weed Seedbank Management: Revisiting How Herbicides Are Evaluated. Weed Science. 2018; 66 (4):415-417.
Chicago/Turabian StyleJason Norsworthy; Nicholas E. Korres; Muthukumar V. Bagavathiannan. 2018. "Weed Seedbank Management: Revisiting How Herbicides Are Evaluated." Weed Science 66, no. 4: 415-417.
Two of the most troublesome weeds in soybean, cotton, and corn in cropping systems of mid-south United States (US) are Senna obtusifolia and Xanthium strumarium. Understanding their population dynamics, particularly weed seedling emergence patterns, is important for the timely implementation and the success of weed management strategies. Identifying the sources of variation of emergence patterns could greatly improve our ability to predict emergence timing. A three-years field study was conducted to determine the effect of environmental conditions on S. obtusifolia and X. strumarium seedling emergence and seedbank potential. The experiment was conducted with two seed sources; X. strumarium burs and S. obtusifolia seeds from a single maternal plant source, and X. strumarium burs and S. obtusifolia seeds from multiple maternal plant sources, both being exposed either to 5 cm burial depth (buried) or left on the soil surface (soil surface) in the fallow or planted in spring after their storage under chilled (chill) or room temperature (no chill) conditions. X. strumarium and S. obtusifolia seedling emergence was lower from burs and seeds that were planted in the soil in September as compared with the chill and/or no chill seeds/burs stored for six months. X. strumarium seedling emergence was reduced from 37 to 1% when burs were left on the soil surface when compared to buried burs. S. obtusifolia seedling emergence was reduced from 47 to 13% when seeds were left on the soil surface as compared to buried. At the end of the experimental period, the soil seedbank of X. strumarium had been significantly depleted, whereas the remaining seeds of S. obtusifolia were viable.
Taghi Bararpour; Nicholas E. Korres. Effect of Simulated Tillage in Combination with Post-Shattering Temperature Conditions on Senna obtusifolia and Xanthium strumarium Seed Survival, Seedling Emergence and Seedbank Potential. Agriculture 2018, 8, 61 .
AMA StyleTaghi Bararpour, Nicholas E. Korres. Effect of Simulated Tillage in Combination with Post-Shattering Temperature Conditions on Senna obtusifolia and Xanthium strumarium Seed Survival, Seedling Emergence and Seedbank Potential. Agriculture. 2018; 8 (4):61.
Chicago/Turabian StyleTaghi Bararpour; Nicholas E. Korres. 2018. "Effect of Simulated Tillage in Combination with Post-Shattering Temperature Conditions on Senna obtusifolia and Xanthium strumarium Seed Survival, Seedling Emergence and Seedbank Potential." Agriculture 8, no. 4: 61.
An integrated weed management strategy that combines various physical, cultural, chemical, and preventive weed control methods would, among other factors, secure a sustainable food production. Agronomic weed control, easily manipulated by the producer set of cultural approaches such as crop density, use of competitive cultivars, or management of nitrogen fertilization, can undoubtedly be a part of integrated weed management strategies particularly when herbicides are not an option. Nevertheless, the multifaceted nature of weed management decision-making procedures, particularly nowadays where the incidences of herbicide-resistant weeds increase dramatically, requires a carefully designed approach for an efficient weed control program to work.
Nicholas Korres. Agronomic Weed Control: A Trustworthy Approach for Sustainable Weed Management. Non-Chemical Weed Control 2018, 97 -114.
AMA StyleNicholas Korres. Agronomic Weed Control: A Trustworthy Approach for Sustainable Weed Management. Non-Chemical Weed Control. 2018; ():97-114.
Chicago/Turabian StyleNicholas Korres. 2018. "Agronomic Weed Control: A Trustworthy Approach for Sustainable Weed Management." Non-Chemical Weed Control , no. : 97-114.
Knowledge of Palmer amaranth demographics and biology is essential for the development and implementation of weed management strategies. A field experiment was conducted to investigate the effects of Palmer amaranth density on seedling mortality, flowering initiation, and flowering progress throughout the growing season and biomass production and fecundity in wide-row soybean. The experimental design was a randomized complete block design with three levels of Palmer amaranth density-clusters: high, medium, and low. Palmer amaranth mortality rate was greater at high Palmer amaranth population density-cluster, reaching a peak within 30 to 40 d after Palmer amaranth emergence (DAE) (0.55 and 0.80 for 2014 and 2015, respectively), in comparison with mortality rate at medium and lower density-clusters. Likewise, as Palmer amaranth density increased, biomass and seed production per unit area of the weed also increased. Biomass production at the high density-cluster in 2014 was 664.7 g m−2compared with 542.9 and 422.1 g m−2at medium and low density-clusters, respectively. Similarly, biomass production at high density-cluster in 2015 was 100.6 g m−2compared with 37.3 and 34.2 at medium and low density-clusters, respectively. In addition, seeds produced at high density-cluster were 1.5 million and 245,400 seeds m−2for 2014 and 2015, respectively. Seed production was reduced by 29% and 54% in 2014 and by 65% and 75% in 2015 at medium and low density-clusters, respectively. Earlier flowering initiation (i.e., between 30 to 40 DAE) occurred in higher Palmer amaranth density-clusters, indicating a trade-off between reproduction and survival at high densities and more stressed environments for species survival. Palmer amaranth male-to-female sex ratio was greater at high densities, 1.3 and 1.9, compared with lower densities of 0.6 to 0.7 and 0.7 to 0.8 in 2014 and 2015, respectively. The plasticity of Palmer amaranth population and population-structure regulation, vegetative growth, and flowering shifts at various levels of intraspecific competition (i.e., high vs. low population density-clusters) and the trade-off between these biological transitions merits further investigation.
Nicholas E. Korres; Jason K. Norsworthy. Palmer Amaranth (Amaranthus palmeri) Demographic and Biological Characteristics in Wide-Row Soybean. Weed Science 2017, 65, 491 -503.
AMA StyleNicholas E. Korres, Jason K. Norsworthy. Palmer Amaranth (Amaranthus palmeri) Demographic and Biological Characteristics in Wide-Row Soybean. Weed Science. 2017; 65 (4):491-503.
Chicago/Turabian StyleNicholas E. Korres; Jason K. Norsworthy. 2017. "Palmer Amaranth (Amaranthus palmeri) Demographic and Biological Characteristics in Wide-Row Soybean." Weed Science 65, no. 4: 491-503.
N.E. Korres; Jason Norsworthy; N.R. Burgos; D.M. Oosterhuis. Temperature and drought impacts on rice production: An agronomic perspective regarding short- and long-term adaptation measures. Water Resources and Rural Development 2017, 9, 12 -27.
AMA StyleN.E. Korres, Jason Norsworthy, N.R. Burgos, D.M. Oosterhuis. Temperature and drought impacts on rice production: An agronomic perspective regarding short- and long-term adaptation measures. Water Resources and Rural Development. 2017; 9 ():12-27.
Chicago/Turabian StyleN.E. Korres; Jason Norsworthy; N.R. Burgos; D.M. Oosterhuis. 2017. "Temperature and drought impacts on rice production: An agronomic perspective regarding short- and long-term adaptation measures." Water Resources and Rural Development 9, no. : 12-27.
The work presented in this study adds to previous research on the occurrence, distribution and growth habitat of common weeds along roadsides in the Mississippi River Delta region of eastern Arkansas, USA. It addresses the relationships between soil properties (i.e. defined as a group of individual soil characteristics or attributes such as P, K, Ca, Mn and other nutrients) and the most agronomically important weeds of which the occurrence at field margins accounted for ≥ 10% of the total sampling sites. These were three broad-leaved weeds (Amaranthus palmeri, Ipomoea spp. and Sida spinosa) and four grass weeds (Echinochloa crus-galli, Urochloa platyphylla, Sorghum halepense and Digitaria sanguinalis). Soil properties were used as explanatory variables for weed occurrence (presence–absence) using partition analysis; the occurrences of the weeds under examination were partitioned by the application of a decision-tree method. The most important soil properties explaining the occurrence of these weeds in field margins were extractable soil nutrients, specifically sodium, boron and copper content, as well as soil physical attributes, in order of importance, bulk density, silt content, field moisture capacity, hydraulic conductivity, wilting point, available water and clay content. Soil chemical properties proved least reliable in explaining weed occurrence at roadside field margins. Knowledge of the relationships between soil properties and weed occurrence can add to our understanding of weed biology and hence enhance the efficiency of weed management strategies. For example, the occurrence of A. palmeri, in soils with high bulk density (>1.4 g cm−3) and low organic matter content (<2.7%) and thus lower residual herbicide activity, will require integrated weed management of this species in field margins. This is of interest given the occurrence of herbicide resistance in roadside arable weeds, mainly A. palmeri, E. crus-galli and S. halepense, in the Mississippi River Delta region of eastern Arkansas and other parts of the world.
N E Korres; Jason Norsworthy; K R Brye; V Skinner; A Mauromoustakos. Relationships between soil properties and the occurrence of the most agronomically important weed species in the field margins of eastern Arkansas - implications for weed management in field margins. Weed Research 2017, 57, 159 -171.
AMA StyleN E Korres, Jason Norsworthy, K R Brye, V Skinner, A Mauromoustakos. Relationships between soil properties and the occurrence of the most agronomically important weed species in the field margins of eastern Arkansas - implications for weed management in field margins. Weed Research. 2017; 57 (3):159-171.
Chicago/Turabian StyleN E Korres; Jason Norsworthy; K R Brye; V Skinner; A Mauromoustakos. 2017. "Relationships between soil properties and the occurrence of the most agronomically important weed species in the field margins of eastern Arkansas - implications for weed management in field margins." Weed Research 57, no. 3: 159-171.
Zonate leaf spot (Gloeocercospora sorghi) is a common disease in Sorghum bicolor producing areas of the U.S., but little is known about its biology, virulence and severity on S. bicolor, Zea mays, and related crop grassweeds. Greenhouse studies were conducted to determine and compare the virulence and severity of G. sorghi on 10 commercially available sorghum hybrids, four Z. mays hybrids and selected grassweed species including Sorghum bicolor (grain sorghum and shattercane biotypes) and Sorghum halepense (Johnsongrass), two of the most problematic arable weeds. Plants from the respective species were inoculated with a local G. sorghi isolate and maintained in a dew-chamber at 24 °C for 24 h and then incubated under greenhouse conditions for 4 weeks. Plants were observed for lesion expression and rated using a modified Horsfall-Barrett scale (0–10). The first symptoms of infection were visible within 24 h following inoculation on shattercane and S. bicolor hybrids. Symptoms consisted of small, non-diagnostic purple lesions on the leaves. Results showed that S. bicolor, S. halepense and shattercane were susceptible to G. sorghi. All other species tested in this study were not infected. More particularly, disease severity, increased from a rating of 3 to 10 on sorghum and from 2 to 7 on S. halepense between 2 and 23 days after inoculation, respectively. However, disease severity on shattercane increased rapidly from 3.5 to 10 between 2 and 8 days after inoculation, respectively. Among the sorghum hybrids tested, FFR-322 appeared to be the most resistant to G. sorghi while Pioneer 83G66 appeared to be the most susceptible. Z. mays hybrids were not infected by the fungus used in this study. G. sorghi could be used effectively to manage shattercane and S. halepense infestations occurring in Z. mays and S. bicolor fields consisting of specific G. sorghi-resistant hybrids.
M. T. Bararpout; Nicholas Korres; T. W. Allen; J. Bond. Infection of Sorghum bicolor, selected grass species and Zea mays by Gloeocercospora sorghi, causal pathogen of zonate leaf spot. Phytoparasitica 2017, 45, 211 -217.
AMA StyleM. T. Bararpout, Nicholas Korres, T. W. Allen, J. Bond. Infection of Sorghum bicolor, selected grass species and Zea mays by Gloeocercospora sorghi, causal pathogen of zonate leaf spot. Phytoparasitica. 2017; 45 (2):211-217.
Chicago/Turabian StyleM. T. Bararpout; Nicholas Korres; T. W. Allen; J. Bond. 2017. "Infection of Sorghum bicolor, selected grass species and Zea mays by Gloeocercospora sorghi, causal pathogen of zonate leaf spot." Phytoparasitica 45, no. 2: 211-217.
Italian ryegrass is a major weed problem in wheat production worldwide. Field studies were conducted at Fayetteville, AR, to assess morphological characteristics of ryegrass accessions from Arkansas and differences among otherLoliumspp.: Italian, rigid, poison, and perennial ryegrass. Plant height, plant growth habit, plant stem color, and node color were recorded every 2 wk until maturity. The number of tillers per plant, spikes per plant, and seeds per plant were recorded at maturity. All ryegrass accessions from Arkansas were identified as Italian ryegrass, which had erect to prostrate growth habit, green to red stem color, green to red nodes, glume (10 mm) shorter than spikelet (19 mm), and medium seed size (5 to 7 mm) with 1 to 3 mm awns. However, significant variability in morphological characteristics was found among Arkansas ryegrass accessions. WhenLoliumspecies at the seedling stage (1- to 2-wk-old plants) were compared, poison ryegrass was characterized as having a large main-stem diameter and wide droopy leaves, whereas perennial ryegrass exhibited a short and a very narrow leaf blade. These two can be distinguished from Italian and rigid ryegrass, which have leaf blades wider than perennial ryegrass but narrower than poison ryegrass. Italian and rigid ryegrass are difficult to distinguish at the seedling stage but are distinct at the reproductive stage. At maturity, Italian ryegrass and poison ryegrass seeds are awned, but perennial and rigid ryegrass seeds are awnless. Poison ryegrass awns were at least 4-fold longer than Italian ryegrass awns. Perennial ryegrass flowered 3 wk later than the other species. Poison ryegrass glumes were longer than the spikelets, whereas Italian ryegrass glumes were shorter than the spikelets. Morphological traits indicate that some Italian ryegrass populations are potentially more competitive and more fecund than others.
Mohammad T. Bararpour; Jason K. Norsworthy; Nilda R. Burgos; Nicholas E. Korres; Edward E. Gbur. Identification and Biological Characteristics of Ryegrass (Loliumspp.) Accessions in Arkansas. Weed Science 2017, 65, 350 -360.
AMA StyleMohammad T. Bararpour, Jason K. Norsworthy, Nilda R. Burgos, Nicholas E. Korres, Edward E. Gbur. Identification and Biological Characteristics of Ryegrass (Loliumspp.) Accessions in Arkansas. Weed Science. 2017; 65 (3):350-360.
Chicago/Turabian StyleMohammad T. Bararpour; Jason K. Norsworthy; Nilda R. Burgos; Nicholas E. Korres; Edward E. Gbur. 2017. "Identification and Biological Characteristics of Ryegrass (Loliumspp.) Accessions in Arkansas." Weed Science 65, no. 3: 350-360.