Weed Science Commons^™

Wayne E. Sabbe Arkansas Soil Fertility Studies 2025, Nathan A. Slaton

Arkansas Agricultural Experiment Station Research Series

Rapid technological changes in crop management and production require that the research efforts be presented in an expeditious manner. The contributions of soil fertility and fertilizers are major production factors in all Arkansas crops. The studies described within will allow producers to compare their practices with the university’s research efforts. Additionally, soil-test data and fertilizer sales are presented to allow comparisons among years, crops, and other areas within Arkansas.

Arkansas Corn And Grain Sorghum Research Studies 2024, Jason Kelley, Travis Faske

Arkansas Agricultural Experiment Station Research Series

The 2024 edition of the Arkansas Corn and Grain Sorghum Research Studies Series includes research results on topics pertaining to corn and grain sorghum production, including weed, disease, nematode, and insect management; economics; irrigation; agronomics; soil fertility; drone use; and research verification program results.

Our objective is to capture and broadly distribute the results of research projects funded by the Arkansas Corn and Grain Sorghum Board. The intended audience includes producers and their advisors, current investigators, and future researchers. The Series serves as a citable archive of research results.

The reports inform and guide our long-term recommendations, but should not …

Wayne E. Sabbe Arkansas Soil Fertility Studies 2024, Nathan A. Slaton

Arkansas Agricultural Experiment Station Research Series

Rapid technological changes in crop management and production require that the research efforts be presented in an expeditious manner. The contributions of soil fertility and fertilizers are major production factors in all Arkansas crops. The studies described within will allow producers to compare their practices with the university’s research efforts. Additionally, soil-test data and fertilizer sales are presented to allow comparisons among years, crops, and other areas within Arkansas.

B.R. Wells Arkansas Rice Research Studies 2023, J. Hardke, X. Sha, N. Bateman

Arkansas Agricultural Experiment Station Research Series

Arkansas is the leading rice producer in the United States. The state represents 49.0% of total U.S. rice production and 49.6% of the total acres planted to rice in 2023. Rice cultural practices vary across the state and across the U.S. However, these practices are also dynamic and continue to evolve in response to changing political, environmental, and economic times. This survey was initiated in 2002 to monitor and record changes in the way Arkansas rice producers approach their livelihood. The survey was conducted by polling county extension agents in each of the counties in Arkansas that produce rice. Questions …

Arkansas Corn And Grain Sorghum Research Studies 2023, Jason Kelley, Travis Faske

Arkansas Agricultural Experiment Station Research Series

The 2023 edition of the Arkansas Corn and Grain Sorghum Research Studies Series includes research results on topics pertaining to corn and grain sorghum production, including weed, disease, and insect management; economics; irrigation; agronomics; soil fertility; mycotoxins; cover crop management; and research verification program results. Our objective is to capture and broadly distribute the results of research projects funded by the Arkansas Corn and Grain Sorghum Board. The intended audience includes producers and their advisors, current investigators, and future researchers. The Series serves as a citable archive of research results.

Vegetation Management During Establishment Of Native Grasses And Forb Plantings On Roadsides And Prairie Restoration, Rachel Woody-Pumford

Graduate Theses and Dissertations

North American prairies have been shrinking due to agricultural production, overgrazing, development of cities and towns, and climate change. However, integrated roadside vegetation management (IRVM) creates the opportunity to reestablish prairies along roadsides through planting native grasses and forbs. Utilizing postememergence (POST) herbicides registered for use along rights-of-way has the potential to remove invasive species and create space for newly establishing native grass and forb species. The use of clopyralid, florpyrauxifen-benzyl, metsulfuron, and quinclorac were found to be safe for use in plantings containing big bluestem (Andropogon gerardii Vitman) and butterfly milkweed (Asclepias tuberosa L.). However, florpyrauxifen-benzyl injured and stunted …

Wayne E. Sabbe Arkansas Soil Fertility Studies 2023, Nathan A. Slaton

Arkansas Agricultural Experiment Station Research Series

Rapid technological changes in crop management and production require that the research efforts be presented in an expeditious manner. The contributions of soil fertility and fertilizers are major production factors in all Arkansas crops. The studies described within will allow producers to compare their practices with the university’s research efforts. Additionally, soil-test data and fertilizer sales are presented to allow comparisons among years, crops, and other areas within Arkansas.

Effect Of Cultural Strategies And Application Technologies On Weed Control In Flooded And Furrow-Irrigated Rice, Noah Hunter Reed

Graduate Theses and Dissertations

Weed control is a major problem that rice (Oryza sativa L.) producers face in the Mid-south every growing season. Restricted use of some rice herbicides has also highlighted the need for more research to be conducted on cultural weed control strategies and application technologies in rice. The aim of these studies was to evaluate rice weed control using various rice row widths, bed widths (irrigation-furrow spacing), rice cultivar selection, and nozzle type selection. Three field experiments were conducted in 2021 and 2022 across four sites at Lonoke, AR, Pine Tree, AR, Rohwer, AR, and Stoneville, MS. In experiment one, as …

Evaluation Of Weed Control Efficacy And Crop Tolerance To Florpyrauxifen-Benzyl Coated Onto Urea, Bodie Lyn Cotter

Graduate Theses and Dissertations

Frequent off-target movement occurrences to soybean [Glycine max (L.) Merr.], rice (Oryza sativa L.) injury, and a lack of barnyardgrass [Echinochloa crus-galli (L.) P. Beauv.] control followed the commercial launch of florpyrauxifen-benzyl in 2018. Florpyrauxifen-benzyl is a synthetic auxin, Herbicide Resistance Action Committee (HRAC)/Weed Science Society of America (WSSA) Group 4 herbicide used for postemergence weed control in rice and labeled for application at 30 g ae ha-1. Previous research documented that soybean was susceptible to injury following spray applications of florpyrauxifen-benzyl at less-than-labeled rates, and certain varieties of rice are less tolerant to spray-applied florpyrauxifen-benzyl at 30 g ae …

Overexpression Of Acetyl Coa Carboxylase 1 And 3 (Accase1 And Accase3), And Cyp81a21 Were Related To Cyhalofop Resistance In A Barnyardgrass Accession From Arkansas, Fidel Gonzalez-Torralva, Jason K. Norsworthy

Crop, Soil and Environmental Sciences Faculty Publications and Presentations

Barnyardgrass [Echinochloa crus-galli (L.) P. Beauv.] is the most difficult-to-control weed species of rice production systems worldwide. It has evolved resistance to different herbicide sites of action, including the acetyl-CoA carboxylase (ACCase)-inhibiting herbicides. Target-site mutations conferring resistance to ACCase-inhibiting herbicides are well documented; however, the role of the different ACCase genes in conferring resistance to cyhalofop-p-butyl (cyhalofop), an ACCase-inhibiting herbicide, remains poorly understood. This research assessed the contribution of gene amplification and expression of ACCase genes in a cyhalofop-resistant barnyardgrass accession. Additionally, the expression of glutathione-S-transferases (GSTs) and cytochrome P450 monooxygenases (P450s) genes as possible …

B. R. Wells Arkansas Rice Research Studies 2022, J. Hardke, X. Sha, N. Bateman

Arkansas Agricultural Experiment Station Research Series

Arkansas is the leading rice producer in the United States. The state represents 50.1% of total U.S. rice production and 49.8% of the total acres planted to rice in 2022. Rice cultural practices vary across the state and across the U.S. However, these practices are also dynamic and continue to evolve in response to changing political, environmental, and economic times. This survey was initiated in 2002 to monitor and record changes in the way Arkansas rice producers approach their livelihood. The survey was conducted by polling county extension agents in each of the counties in Arkansas that produce rice. Questions …

Assessment Of Dicamba And 2,4-D Residues In Palmer Amaranth And Soybean, Maria Leticia Zaccaro-Gruener, Jason K. Norsworthy, Leonard B. Piveta, L. Tom Barber, Andronikos Mauromostakos

Crop, Soil and Environmental Sciences Faculty Publications and Presentations

Off-target movement of 2,4-D and dicamba is sometimes to blame as the cause of symptoms observed in weeds growing in production fields. Pesticide regulatory authorities routinely sample tissues of weeds or crops from fields under investigation for potential illegal use of auxin herbicides. This research aimed to determine if analytical tests of herbicide residue on soybean or Palmer amaranth vegetation treated with dicamba or 2,4-D could be used to differentiate between rates applied and how the residue levels decay over a 1-mo interval. Four rates of each herbicide (1X, 0.1X, 0.01X, and 0.001X) were applied, with a 1X rate of …

Arkansas Corn And Grain Sorghum Research Studies 2022, Victor Ford, Jason Kelley, Nathan Mckinney Ii

Arkansas Agricultural Experiment Station Research Series

The 2022 edition of the Arkansas Corn and Grain Sorghum Research Studies Series includes research results on topics pertaining to corn and grain sorghum production, including weed, disease, and insect management; economics; sustainability; irrigation; post-harvest drying; soil fertility; mycotoxins; cover crop management; and research verification program results. Our objective is to capture and broadly distribute the results of research projects funded by the Arkansas Corn and Grain Sorghum Board. The intended audience includes producers and their advisors, current investigators, and future researchers. The Series serves as a citable archive of research results.

Reports in this publication are 2–3 year summaries. …

Effect Of Rice Leaf Stage On Tolerance To Benzobicyclon In A Drill-Seeded Production System, Jake A. Patterson, Jason K. Norsworthy, Thomas R. Butts, Edward E. Gbur

Crop, Soil and Environmental Sciences Faculty Publications and Presentations

Benzobicyclon is a new postflood-applied herbicide that was registered for use in U.S. rice (Oryza sativa L.) in 2021 by Gowan Company. Therefore, research was conducted to evaluate tolerance of commonly grown rice cultivars to benzobicyclon. In 2018 and 2019, field experiments were conducted near Stuttgart, AR to evaluate the influence of growth stage on rice tolerance to benzobicyclon, and to evaluate pure line and hybrid rice tolerance to benzobicyclon following repeated use of acetolactate synthase-inhibiting herbicides. In one of two years, rice growth stage (leaf number) at application impacted tolerance to benzobicyclon. In 2018, the two-leaf application of …

Herbicide Physiology And Environmental Fate, Luis Avila, Nilda Roma-Burgos

Crop, Soil and Environmental Sciences Faculty Publications and Presentations

Editorial

Herbicide Physiology and Environmental Fate

Fenclorim Rice Safening And Weed Control With Fall-Applied Acetochlor And Pyroxasulfone, Tristen H. Avent, Jason K. Norsworthy, Thomas R. Butts, Trenton Roberts, Nicholas R. Bateman

Crop, Soil and Environmental Sciences Faculty Publications and Presentations

Applications of very long-chained fatty acid elongase (VLCFA)-inhibiting herbicides are currently not labeled within U.S. rice (Oryza sativa L.) production but have been used in Asian rice production to suppress weedy rice and control other annual grasses and small-seeded broadleaves. Therefore, separate experiments were initiated in the fall of 2019 and 2020 to evaluate rice tolerance and weedy rice (O. sativa L.) control with acetochlor and pyroxasulfone in the following spring. A three-factor experiment within a randomized complete block design was implemented with the factors being (1) herbicide choice (acetochlor or pyroxasulfone), (2) a low or high herbicide …

Assessment Of Efficacy And Mechanism Of Resistance To Soil-Applied Ppo Inhibitors In Amaranthus Palmeri, Gulab Rangani, Aimone Perri, Reiofeli A. Salas-Perez, Jens Lerchl, Srikanth Kumar Karaikal, Juan Camilo Velásquez, Nilda Roma-Burgos

Crop, Soil and Environmental Sciences Faculty Publications and Presentations

Resistance to protoporphyrinogen oxidase (PPO) inhibitors in Palmer amaranth is a major concern, given the high selection pressure and increasing number of populations with reduced sensitivity to PPO herbicides in the US. We evaluated the effect of five soil-applied herbicides on Palmer amaranth (Amaranthus palmeri S. Wats.) populations collected in 2014 and 2015 in Arkansas, USA. Soil-applied saflufenacil, sulfentrazone, and flumioxazin reduced the seedling emergence 91–100%; however, fomesafen and oxyfluorfen showed reduced (63–90%) efficacy on some populations. Target-site mutation (TSM) is the major mechanism of resistance to PPO herbicides; therefore, six populations showing resistance to soil-applied fomesafen were selected for …

Evaluation Of Rice Tolerance And Weed Control With Acetochlor And Fenclorim, Tristen H. Avent, Jason K. Norsworthy, Thomas R. Butts, Trenton L. Roberts, Nicholas R. Bateman

Crop, Soil and Environmental Sciences Faculty Publications and Presentations

Many problematic weeds have evolved resistance to herbicides in mid-southern U.S. rice fields. With the lack of new effective herbicides, rice producers seek alternatives that are currently not labeled for rice production. Inhibitors of very-long chain fatty acid elongase (VLCFA) are currently not labeled for use with U.S. rice crops but are labeled for use in other U.S. row cropping systems and rice production in Asia. Previous research has demonstrated the utility of VLCFA inhibitors for weed control in rice; however, these herbicides induce variable amounts of injury to the crop when applied early in the growing season. Experiments were …

Rice Tolerance To Acetochlor With A Fenclorim Seed Treatment, Tristen H. Avent, Jason K. Norsworthy, Thomas R. Butts, Trenton Roberts, Nicholas R. Bateman

Crop, Soil and Environmental Sciences Faculty Publications and Presentations

Rice producers in the United States need effective herbicides to control problematic weeds. Previous research has demonstrated that acetochlor can provide in-season weed control in rice; however, undesirable injury is common. Thus, trials were initiated in 2020 and 2021 to evaluate 1) rice cultivar tolerance to microencapsulated (ME) acetochlor with the use of a fenclorim seed treatment at 2.5 g ai kg⁻¹ of seed; 2) a dose-response of a fenclorim seed treatment with ME acetochlor; and 3) rice tolerance to fenclorim and ME acetochlor under cool, wet conditions. For all trials, acetochlor was applied delayed-preemergence (4 to 7 d …

B.R. Wells Arkansas Rice Research Studies 2021, J. Hardke, X. Sha, N. Bateman

Arkansas Agricultural Experiment Station Research Series

Arkansas is the leading rice producer in the United States. The state represents 47.5% of total U.S. rice production and 47.8% of the total acres planted to rice in 2021. Rice cultural practices vary across the state and across the U.S. However, these practices are also dynamic and continue to evolve in response to changing political, environmental, and economic times. This survey was initiated in 2002 to monitor and record changes in the way Arkansas rice producers approach their livelihood. The survey was conducted by polling county extension agents in each of the counties in Arkansas that produce rice. Questions …

Arkansas Corn And Grain Sorghum Research Studies 2021, Victor Ford, Jason Kelley, Nathan Mckinney Ii

Arkansas Agricultural Experiment Station Research Series

The 2021 edition of the Arkansas Corn and Grain Sorghum Research Studies Series includes research results on topics pertaining to corn and grain sorghum production, including weed, disease, and insect management; economics; sustainability; irrigation; post-harvest drying; soil fertility; mycotoxins; cover crop management; and research verification program results. Our objective is to capture and broadly distribute the results of research projects funded by the Arkansas Corn and Grain Sorghum Board. The intended audience includes producers and their advisors, current investigators, and future researchers. The Series serves as a citable archive of research results.

Economic Viability Of Weed Management Strategies In High-Tunnel Tomato, Gracie Morrison

Crop, Soil and Environmental Sciences Undergraduate Honors Theses

Cost-effective weed suppression is an important consideration for tomato growers. Growers often choose methods which minimize hand labor, as hand weeding can be prohibitively expensive. This project determined economic viability of high tunnel tomatoes treated with several methods of weed control, both organic and chemical. These methods included: 2-week hand weeding, 1-week hand weeding, preemergent, straw, landscape fabric, and untreated weedy control plots. These treatments were applied to randomized blocks in a high-tunnel. Weeding, planting, and harvest were all timed to determine labor and material costs of weed management strategy implementation. After harvest, marketable yield was weighed to determine revenue. …

Examining The Invasion Of Bush Honeysuckle Through A Phylogenetic Analysis, Phoebe Bruffett

Biological Sciences Undergraduate Honors Theses

The mechanisms underlying the continual spread of invasive plants within their respective non-native ranges is a major focal point to invasion research. Many theories have been proposed to understand these invasions, each with different implications for the predicted range for invasive plants. Lonicera maackii provides an exceptional opportunity to examine the effectiveness of these theories to explain the trends of invasive plants. Lonicera maackii is native to eastern Asia, but has invaded much of the eastern United States, presenting a severe threat to the health of forest and other natural areas. Recent analysis of the climatic envelopes uncovered a significant …

Wayne E. Sabbe Arkansas Soil Fertility Studies 2021, Nathan A. Slaton

Arkansas Agricultural Experiment Station Research Series

Rapid technological changes in crop management and production require that the research efforts be presented in an expeditious manner. The contributions of soil fertility and fertilizers are major production factors in all Arkansas crops. The studies described within will allow producers to compare their practices with the university’s research efforts. Additionally, soil-test data and fertilizer sales are presented to allow comparisons among years, crops, and other areas within Arkansas.

Evaluation Of Benzobicyclon In Midsouth Rice (Oryza Sativa) Production Systems, Jake Patterson

Graduate Theses and Dissertations

Controlling weedy rice postemergence is challenging for rice producers in the United States because of the lack of herbicide options. Weedy rice is genetically similar to cultivated rice, thus making it difficult to control with mid-season postemergence herbicide applications without also damaging the crop. Hence, there is a need for a new effective postemergence weedy rice control herbicide. Findings from this research indicate that the use of benzobicyclon in current standard quizalofop- and imidazolinone-resistant rice herbicide programs provides tremendous utility for Midsouth rice producers. In both of these production systems, the addition of benzobicyclon to the respective standard herbicide programs …

Evaluation Of Fenclorim Safener For Use In Rice With Group 15 Herbicides, Tristen Heath Avent

Graduate Theses and Dissertations

The development of herbicide resistance and the lack of effective herbicides to control problematic weeds has caused Arkansas rice (Oryza sativa L.) production to pursue alternative sites of action. Currently, very long-chain fatty acid elongase inhibitors are not labeled for U.S. rice production but have been widely used for Asian rice production systems. Previous research has demonstrated the utility of acetochlor and pyroxasulfone to provide in-season weed control for Arkansas rice production, but variable crop tolerance has been observed. Additionally, acetochlor at 1,260 g ai ha-1 elicited less rice injury when seeds were treated with a herbicide safener seed treatment …

Evaluation, Characterization, And Utilization Of Weed-Suppressive Sweetpotato Cultivars For Sustainable Weed Management, Isabel Schlegel Werle

Graduate Theses and Dissertations

Sweetpotato (Ipomoea batatas L.) is a low-technology, subsistence crop that enhances food and nutrition security particularly in developing nations. Weed interference with the crop can reduce sweetpotato storage root yields and product quality. Current weed management practices in sweetpotato include PRE or POST herbicides application, cultivation, mowing, or handweeding. Unlike row crops, herbicide options for sweetpotato are few; therefore, alternative weed control practices are needed. The overall objective of this research was to determine the weed suppressive ability of several sweetpotato cultivars. This research also provides information about cover crop use for weed suppression in sweetpotato production in Arkansas. Field …

Mitigating Rice Injury Caused By Florpyrauxifen-Benzyl And Optimizing Florpyrauxifen-Benzyl Rate And Timing For Use In Furrow-Irrigated Rice, James Winston Beesinger

Graduate Theses and Dissertations

Florpyrauxifen-benzyl (synthetic auxin, WSSA Group 4) is a postemergence, broad-spectrum herbicide labeled for use in Mid-South rice (Oryza sativa L.) production. Introduction of florpyrauxifen-benzyl to Arkansas rice production led to observations of varying levels of injury caused by the herbicide across cultivars and environments. Findings from previous research indicated hybrid long-grain rice and medium-grain rice were more susceptible to florpyrauxifen-benzyl and hypotheses were formed using this research regarding the impact of environmental conditions on the amount of injury observed. Concerns of yield loss, delay in maturity and loss of groundcover as well as questions regarding the ability of florpyrauxifen-benzyl to …

Integrated Weed Management Strategies For Palmer Amaranth (Amaranthus Palmeri) In Cotton And Soybean Production Systems, Rodger Bruce Farr

Graduate Theses and Dissertations

Management of Palmer amaranth [Amaranthus palmeri (S.) Wats.] in the Midsouth in soybean [Glycine max (L.)] and cotton (Gossypium hirsutum L.) production systems has become increasingly troublesome due to resistance to many of the commonly utilized herbicides in these systems. Developments have been made to utilize new chemistries as well as incorporate integrated weed management strategies to control Palmer amaranth, but questions have risen given the economic feasibility or effectiveness of these new strategies. Additionally, regulation has limited producers’ abilities to utilize some herbicide chemistries. As a result, experiments were conducted to 1) understand the utility of isoxaflutole in isoxaflutole-tolerant …

Palmer Amaranth [Amaranthus Palmeri (S.) Wats.] Resistance To S-Metolachlor In The Mid-Southern Us And S-Metolachlor Dissipation In Soil, Koffi Badou Jeremie Kouame

Graduate Theses and Dissertations

Palmer amaranth [Amaranthus palmeri (S.) Wats.] presents both a high genetic diversity and propensity to evolve resistance to herbicides of several sites-of-action which have made it one of the worst weeds in US agriculture. In Arkansas, Palmer amaranth is resistant to herbicides of seven sites-of-action, which are 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) inhibitor, acetolactate synthase inhibitors, microtubule inhibitors, protoporphyrinogen oxidase inhibitors, very long chain fatty acid inhibitors, glutamine synthetase inhibitors, and hydroxyphenylpyruvate dioxygenase inhibitors. Sustainable management requires a better understanding of its biology and that of herbicide environmental fate. This research had five objectives: 1) characterize the current status of Palmer amaranth …