Weed Science Commons^™

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 …

Beyond The Boom: Integrated Approaches To Managing Weeds And Brush, M. L. Treadwell, D. Burson

IGC Proceedings (1997-2023)

William Bray stated in his 1904 report, The Timber of the Edwards Plateau of Texas, "This struggle of the timberlands to capture the grasslands is an old warfare....it spreads like infection.” This trend is true today and especially pronounced in the Great Plains, where only 1/4 of the Great Plains’ original grasslands remains intact. Species like honey mesquite, honey locust, black locust, sumac, dogwood, post oak, winged elm, Siberian elm, salt cedar, huisache, Eastern redcedar, Ashe and redberry juniper, pricklypear, sericea lespedeza, and many other species represent alarming rates of spread and rapid establishment throughout Great Plains grasslands. Although, these …

Forage Response And Economic Benefits To Weed Management In Grasslands, E. S. Flynn, S. Ingram, B. B. Sleugh

IGC Proceedings (1997-2023)

A common question among managers of grazing operations is “At what level of weed pressure does it become economical to apply herbicides on pastures?” Unfortunately, there isn’t just one answer to this question as production goals and practices differ between operations and even within an operation over time. Regardless, the real question being ask is if weed control will increase profit per acre.

There are three basic avenues that may be taken to improve profit per acre through weed control. The first is to increase the carrying capacity of the grazing operation by controlling weeds and replacing them with desirable …

Field Testing Of A Turnip Growing Protocol On New Zealand Dairy Farms, J. P. J. Eerens, P. M. S. Lane

IGC Proceedings (1997-2023)

Summer droughts are a regular occurrence in central North Island districts of New Zealand, which causes pastures to wilt, lose their nutritive value and stop growing. The resulting summer feed gap depresses farm productivity (Clark et al., 1996). Turnips optimally sown mid-late October (more often sown in November or even December) are grown to fill this feed gap. Recorded average yields of 7.4 t dry matter (DM)/ha are below the economic breakeven point of 8-10 t DM/ha (Clark et al., 1996). A turnip growing protocol was developed from published data (Eerens & Lane 2004) and tested on commercial …

Belowground Plant Communities: Seed Bank Dynamics And Relationship To Aboveground Vegetation In Grazing Allotment Of Klamath County, Oregon, Dellaina C. Morse, Scott M. Estepa

Environmental Science & Management Senior Capstones

Seed banks are valuable resources for restoration but are understudied. The species present in the aboveground composition influence the seed bank through seed inputs. Land managers utilize herbicides to selectively reduce certain species in the above- and belowground composition. The aim of this paper is to observe and assess the species present in a seed bank post-herbicide application, and to discuss the seed bank potential for future restoration at the specific site in Klamath County, Oregon. Soil core samples were collected in the field and brought to the lab where they were processed and prepared for germination. We watered and …

Effect Of Corn Row Spacing On Herbicide Effectiveness For Weed Control In 2022, S. H. Lancaster, E. Adee

Kansas Agricultural Experiment Station Research Reports

Cultural weed control practices such as narrow row spacing can be a key component of successful weed management. Experiments were conducted in the Kansas River Valley to evaluate interactions of herbicide programs and corn row spacings on weed control and grain yield. There were no differences in weed control at a site with low weed density. However, at a site with high Palmer amaranth density, Resicore applied to 15- and 30-inch rows and Bicep + Acuron applied to 15-inch rows resulted in the greatest weed control. Corn yield was similar across all treatments at both locations.

A Bioassay To Determine Poa Annua Responses To Indaziflam, Benjamin D. Pritchard

Masters Theses

Herbicide resistance within Poa annua is widespread in managed turfgrass systems. In 2020, a P. annua collection from a golf course in the southeastern United States was reported to be resistant to indaziflam as well as six other mode-of-action groups. Considering P. annua is the most troublesome weed in turfgrass, a bioassay to screen other collections with putative indaziflam resistance is needed. A dose-response experiment was conducted with ten concentrations of indaziflam (0, 250, 500, 750, 1000, 1250, 1500, 2000, 4500, and 9000 pM) in Gelrite® culture during 2021 and 2022. An herbicide-susceptible (S1) collection of P. annua, a …

Single And Split Herbicide Applications For Efficacy In Corn, R. S. Currie, P. W. Geier

Kansas Agricultural Experiment Station Research Reports

The objective of this study was to compare season-long weed control from single and sequential herbicide applications in corn. Control of all weed species was generally good (90% or more) early in the season regardless of preemergence (PRE) herbicide. However, Russian thistle and Palmer amaranth control was best later in the season when a PRE herbicide was followed by a postemergence (POST) treatment. While all herbicide treatments increased yields compared to the untreated control, yields were greatest when Lumax EZ PRE (atrazine/mesotrione/metolachlor) was followed by Acuron (atrazine/bicyclopyrone/mesotrione/metolachlor) and glyphosate POST.

Response Of Conventional Sorghum To Imiflex, Zest Wdg, And Firstact, R. Liu, V. Kumar, M. Marrs, T. L. Lambert

Kansas Agricultural Experiment Station Research Reports

Grass weed control in sorghum has been a serious challenge for sorghum growers. The newly developed herbicide-tolerant (HT) sorghum technologies such as igrowth, Inzen, and Double Team sorghum will allow growers to use IMIFLEX, ZestWDG, and FirstAct respectively, for in-season weed control. However, the adoption of these HT sorghum technologies may increase the use of these labeled herbicides and increase the likelihood of herbicide drift or tank contamination to conventional sorghum. Three separate field studies were conducted at Kansas State University Agricultural Research Center (KSU-ARCH) near Hays, KS, to understand the response of conventional sorghum to various rates of IMIFLEX, …

Evaluation Of Alternate Wetting And Drying Irrigation Management In Rice, Richard Lee Atwill Ii

Theses and Dissertations

Water level declines in the Mississippi River Valley Alluvial Aquifer (MRVAA) are attributed largely to withdrawals for rice (Oryza sativa L.) irrigation. This study was performed to determine if alternative irrigation strategies for rice could reduce withdrawal from the MRVAA without having an adverse effect on grain yield, grain quality, control of barnyardgrass, and profitability. Research was conducted in Stoneville, MS and 19 on-farm locations across the Delta region of Mississippi from 2014 through 2017 to determine the irrigation threshold for alternate wetting and drying (AWD) rice irrigation, the effect of AWD management on barnyardgrass control, and effects of …

Mitigation Of Herbicide Resistance Development Among Weed Species In Cotton And Peanut, Justin S. Calhoun

Theses and Dissertations

Herbicide resistance development among weed populations in cotton and peanut is becoming increasingly difficult to manage. If resistant populations continue to persist, weed control practices for producers will become less efficient and more costly. The objective of this research was to evaluate alternative weed control techniques designed to mitigate herbicide resistance development for their agronomic and economic impact on weed management systems. Studies were conducted in 2019, 2020, and 2021 at multiple locations in Mississippi and Arkansas investigating multiple techniques including the addition of soil surfactants in herbicide tank mixtures, increasing SOAs utilized in peanut herbicide programs, applying non-labeled herbicides …

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 …

The Impacts Of Imazapic On Garlic Mustard And Non-Target Forest Floor Vegetation In Central Kentucky’S Hardwood Forests, Pavan Kumar Podapati

Theses and Dissertations--Forestry and Natural Resources

Alliaria petiolata is an invasive biennial herb that poses a substantial threat to various ecosystems across the United States. Imazapic herbicide can control A. petiolata infestations, but there is limited peer-reviewed data on impacts of pre-emergent imazapic spraying to forest floor communities. This research examined the impacts of pre-emergent imazapic (0.84 kg/ha) with Pentra-Bark® surfactant on ground cover of A. petiolata and the spring perennials Claytonia virginica and Erigenia bulbosa. Experimental populations in randomized blocks within two forest stands in central Kentucky received the following treatments at 0.84 kg ai/ha: imazapic with Pentra-Bark®, glyphosate with Pentra-Bark®, Pentra-Bark® alone, and …

Crop Response To Low-Dose Dicamba, Mason Castner

Graduate Theses and Dissertations

The introduction of dicamba-resistant (DR) soybean [Glycine max (L.) Merr.] and cotton (Gossypium hirsutum L.) followed by a label allowing over-the-top applications of dicamba in the 2017 provided growers an additional option for broadleaf weed control. Because non-DR soybean is sensitive to low concentrations of dicamba, postemergence dicamba applications present growers choosing to plant non-DR soybean with concerns of damage from off-target movement through physical drift and volatilization of the herbicide as well as tank-contamination from prior dicamba application. Consequences of low-dose dicamba exposure on sensitive vegetative and reproductive soybean have been well researched, but little is known regarding the …

Mitigating Herbicide Impacts To Soybean, Grant Lawson Priess

Graduate Theses and Dissertations

The rapidity in evolution of herbicide-resistant weeds and the resulting cost to U.S. farmers demonstrate the need to responsibly steward the limited number of herbicides available in agricultural systems. To reduce weed emergence and likewise added selection pressures placed on herbicides, early-season crop canopy formation has been promoted. However, impacts to soybean following a potentially injurious herbicide application have not been thoroughly evaluated. Therefore, field experiments were conducted to determine whether: 1) soybean injury from metribuzin or flumioxazin delayed canopy formation or changed the incidence of pathogen colonization; 2) residual herbicides applied preplant reduced the potential for soybean injury and …

Control Of Protoporphyrinogen Oxidase-Resistant Palmer Amaranth, Michael Mckinley Houston

Graduate Theses and Dissertations

Already one of the most troublesome weeds in row crop production in the southern U.S., protoporphyrinogen oxidase (PPO)-resistant Palmer amaranth [Amaranthus palmeri (S.) Wats.] was first documented in Arkansas in 2015. Since this confirmation, PPO-resistant Palmer amaranth has been identified throughout the Midsouth. The following research evaluated both current and future herbicide programs for controlling PPO-resistant Palmer amaranth and quantified field-level resistance to PPO-inhibiting herbicides. On-farm research, located in fields with confirmed PPO-resistant Palmer amaranth, was conducted in 2016 and 2017. In preemergence (PRE) herbicide experiments, PPO-inhibiting herbicides still proved useful when combined with herbicides such as metribuzin and/or pyroxasulfone. …

Exploring Alternative Giant Salvinia (Salvinia Molesta D.S. Mitchell) Management Strategies, Bradley T. Sartain

LSU Doctoral Dissertations

Dense infestations of the free-floating aquatic fern giant salvinia (Salvinia molesta D.S. Mitchell) have been expanding across the southeastern United States for over two decades. Although herbicide programs have provided relief to giant salvinia infested areas, morphology and growth characteristics make management difficult. A series of mesocosm trials were conducted to explore alternative management strategies for giant salvinia. Evaluation of non-registered aquatic herbicides showed that rates of sulfometuron and metsulfuron controlled giant salvinia and provided a 98 to 100% biomass reduction. An outdoor mesocosm trial evaluated potential glyphosate resistance in giant salvinia in select water bodies throughout Louisiana. Differences …

Determining Growth Characteristics And Control Programs For Nealley's Sprangletop (Leptochloa Nealleyi Vasey), Trace Buck

LSU Master's Theses

ABSTRACT

Research was conducted at the LSU AgCenter Dean Lee Research and Extension center near Alexandria, La in 2016 and 2017 to evaluate the growth characteristics and control of Nealley’s sprangletop. Nealley’s sprangletop is a relatively new weed with little research available to understand its growth habit and effective control strategies.

Nealley’s sprangletop undergoes a more drastic height increase of 212 to 742 mm, 4 to 6 WAE than Amazon sprangletop 377 to 612 mm in the same time frame. Averaged across harvest interval tiller and leaf number of Nealley’s sprangletop was approximately 50 and 40% less than Amazon sprangletop. …

Late Summer Prescribed Fire And Fall Herbicide Application Show Strong Suppressive Effects On Sericea Lespedeza Frequency And Vigor, G. A. Gatson, W. H. Fick, W. W. Hsu, K C. Olson

Kansas Agricultural Experiment Station Research Reports

Objective:The objective of this study was to evaluate the efficacy of a one-time application of late summer prescribed fire followed by fall herbicide application for substantially reducing sericea lespedeza frequency and vigor.

Study Description:A single 80-acre native tallgrass pasture was divided into 16 units. Each of these units was either burned in early September (burn only), sprayed with Escort XP (DuPont, Wilmington, DE) in late September (spray only), burned in early September and subsequently sprayed in late September (burn + spray), or neither burned nor sprayed (control). Sericea lespedeza frequency and vigor was measured shortly before …

Characterization Of Multiple-Herbicide-Resistant Echinochloa Colona From Arkansas, Christopher Edward Rouse

Graduate Theses and Dissertations

Echinochloa species are highly adaptive weeds that have the potential to impact crops in a variety of environments. This has positioned them as the most problematic weeds in a number of USA cropping systems with some species having the distinction of the 'worst herbicide-resistant weeds' in the world. Recent evidence has positioned Echinochloa colona (junglerice) as the most dominant in Arkansas and throughout the Mid-South, USA, especially in rice (Oryza sativa L.) and soybean (Glycine max L.) production fields. A history of extensive herbicide-use for management and a lack of integrated or diverse approaches to management have led to rampant …

Scope And Influence Of Enhanced Triazine Degradation In U.S. Soils, Ethan Trent Parker

Doctoral Dissertations

The triazines are one of the most widely used herbicide classes ever developed, and play a role in managing herbicide-resistant weed populations in sustainable agricultural production systems. The triazines are traditionally valued for their persistence and season-long weed control in over 50 crops including corn, soybeans, wheat, and vegetables. The literature suggests that atrazine, the most widely used triazine, may no longer remain persistent in soils due to enhanced microbial degradation. Experiments examined the rate of degradation of atrazine and two other triazine herbicides: simazine and metribuzin in both atrazine adapted and non-adapted soils from across the United States. Additional …

Prioritizing The Management Of Arundo Donax: Recommendations For Removal And Revegetation In California Riparian Habitats, Matthew S. Waterworth

Master's Projects and Capstones

The highly invasive grass species, giant reed (Arundo donax), has been a major contributor to riparian habitat degradation in California for over 50 years. Several modes of vegetative reproduction have allowed this alien species to take advantage of fluvial processes and rapidly spread within California watersheds. A. donax dramatically alters hydrologic regimes, displaces native vegetation, and removes food and habitat for native wildlife. It is widely accepted that removal of this invasive on a watershed scale is critical to restore natural riparian processes and facilitate the reestablishment of native flora and fauna. The following study analyzed the efficacy of …

Potential Interaction Between Pre- And Post-Emergence Herbicides And The Efficacy Of Insecticide And Fungicide Seed Treatments In Cotton, Cory Joseph Vineyard

Masters Theses

An apparent reduction in the performance of neonicotinoid seed treatments in controlling thrips, especially in cotton, has been observed, which has coincided with the increased use of both pre- and post-emergence herbicides to control glyphosate-resistant weeds. The objective of this research was to evaluate the potential interactions of both pre- and post-emergence herbicides on the efficacy of insecticide and fungicide seed treatments in cotton

Aldicarb along with imidacloprid and thiamethoxam seed treatments reduced thrips numbers compared with non-treated seed. However, thiamethoxam did not provide effective control. Some pre-emergence herbicide treatments reduced plant health. While there was evidence that thrips injury …

Influence Of Aminocyclopyrachlor Plus Metsulfuron On Seedhead Development And Forage Quality In Tall Fescue, Trevor Davis Israel

Doctoral Dissertations

This research quantified the level of seedhead suppression, injury, total ergot alkaloid changes, and forage quality changes in endophyte-infected tall fescue resulting from spring applications of aminocyclopyrachlor (ACP) plus metsulfuron (MET). Results indicated that ACP plus MET reduced tall fescue seedhead density 53 to 55% but also reduced yield 39 to 51% at spring harvest. ACP plus MET also reduced total ergot alkaloid concentration 28 to 34% and improved crude protein (CP) and relative forage quality (RFQ).

This research also determined the impact of ACP plus MET application timing and rate on tall fescue injury and weed control. Spring and …

Fallow Weed Control With Preemergence Tank Mixes Of Sharpen, Zidua, Sencor, Banvel, Atrazine, Balance Pro, And Corvus, R. Currie, P. Geier

Kansas Agricultural Experiment Station Research Reports

With the exception of the tank mix of Sharpen and Sencor, all other tank mixes that provided 100% kochia control 53 days after treatment (DAT) were three-way tank mixes of atrazine herbicide plus, Banvel, and Balance Pro or Zidua. Only two tank mixes provided 98% kochia control 143 DAT. These were also three-way tank mixes of these chemistries. Combinations of Balance Pro and Sencor were needed to provide greater than 93% control of Russian thistle 143 DAT. No tank mix provided good control of Palmer amaranth 143 DAT. However, tank mixes of Sharpen, Sencor, and Zidua provided 84% control 143 …

Efficacy Of Anthem, Anthem Atz, Solstice, Keystone Nxt, Corvus, And Surestart Ii In Glyphosate-Resistant Irrigated Corn, R. Currie, P. Geier

Kansas Agricultural Experiment Station Research Reports

The best treatments provided excellent green foxtail, crabgrass, or shattercane control. All treatments dramatically increased corn yield compared to the control.

Herbicide Evaluation For Control Of Kochia And Palmer Amaranth In Teff Grass, J. D. Holman, C. Thompson, T. Roberts, S. Maxwell

Kansas Agricultural Experiment Station Research Reports

Eleven postemergence herbicide treatments were applied to teff grown for forage to evaluate Palmer amaranth and kochia control, as well as crop tolerance. Effective Palmer amaranth control was achieved with all herbicide treatments, while less than satisfactory kochia control was obtained with atrazine and Harmony. Clarity, 2,4-D, and Huskie applied alone appeared to control kochia, but kochia density was low in the plots. Had the kochia population been higher, similar efficacy ratings may have been attained. Huskie or atrazine caused the most injury to teff. The first harvest suggests these herbicides reduced forage yield to less than 3,000 lb/a.

Palmer Amaranth Control And Sorghum Response To Tank Mixtures Of Huskie, R. Currie, P. Geier

Kansas Agricultural Experiment Station Research Reports

Although Huskie treatments caused significant chlorosis, the sorghum recovered fully and chlorosis did not affect yield. All tank mixes of Huskie provided good Palmer amaranth control at all rating dates. Starane NXT provided poor Palmer amaranth control at all rating dates. All tank mixes of Huskie significantly elevated yield compared to the untreated controls or Starane NXT treatments.

Efficacy Of Lumax Ez, Atrazine, Acuron, Armezon, Sharpen, Outlook, Verdict, And Prowl H2o In Irrigated Glyphosate-Resistant Corn, R. Currie, P. Geier

Kansas Agricultural Experiment Station Research Reports

All treatments provided statistically superior control of Palmer amaranth compared to the control or a single application of glyphosate. All treatments provided excellent control of all other weed species. Although all herbicide tank mixes elevated corn yield compared to the control, there were no statistically significant differences among herbicides in their ability to do so.

Crop Updates 2011 - Farming Systems, Janette Drew, Rob Grima, Bob French, Raj Malik, Mark Seymour, Christine Zaicou-Kunesch, Glenn Mcdonald, Brendon Nicholas, Dennis Van Gool, James Fisher, Peter Tozer, Doug Abrecht, Michael Robertson, Cameron Weeks, Michael O'Conner, Peter Newman, Mike Clarke, Andrew Blake, Gordon Macaulay, Vijay Jayasena, Syed M. Nasar-Abbas, Larisa Cato, Robert Loughman, Ken Quail

Crop Updates

This session covers twelve papers from different authors:

1. Fallowing 50% of the farm each year – does it pay? Janette Drew and Rob Grima

Department of Agriculture and Food

2. How crop sequences affect the productivity and resilience of cropping systems in two Western Australian environments, Bob French, Raj Malik, Mark Seymour, Department of Agriculture and Food

3. When is continuous wheat or barley sustainable? Christine Zaicou-Kunesch and Rob Grima Department of Agriculture and Food

4. Identifying constraints to bridging the yield gap, Glenn McDonald, Department of Agriculture and Food

5. Land constraints limiting wheat yields in …