Agronomy and Crop Sciences Commons^™

Mitigating The Risk For Glufosinate Resistance, Christopher John Meyer

Graduate Theses and Dissertations

While glufosinate-resistant weeds have not yet been identified in U.S. row crops, rapid evolution of glyphosate-resistance, and resulting cost to U.S. farmers, demonstrates the need to responsibly steward the limited number of herbicides available in agricultural systems. Field and laboratory experiments were conducted to: 1) Identify herbicide interactions that can occur in Enlist™ and Roundup Ready® Xtend® systems; 2) Identify herbicide interactions that occur when glufosinate is mixed with fomesafen, clethodim, and glyphosate; 3) Determine the optimum rate structure and application timings when multiple POST applications of glufosinate are applied to LibertyLink soybean; 4) Use 14C techniques to determine why …

Relative Contribution Of Physical Interference And Allelopathy To Weed Suppression By Winter Annual Cover Crop Mixtures, Alyssa D. Travlos

MSU Graduate Theses

Cover cropping systems are widely used in crop production systems to prevent erosion, improve soil health, and suppress weeds. Common cover cropping systems include combinations of cereal rye (Secale cereale L.), Brassica species, legumes, and other winter annual species. Three cover crop mixtures (cereal rye alone, cereal rye plus winter pea, and cereal rye plus winter pea plus radish) were applied using three methods (fresh residue, dried leached residue, and leachate) to common waterhemp (Amaranthus tuberculatus var. rudis) and large crabgrass [Digitaria sanguinalis (L.) Scop.]. The experiment was conducted once in a greenhouse and once in a …

Weed Control And Management For Vegetable Soybeans In Arkansas, Seth Bernard Abugho

Graduate Theses and Dissertations

Vegetable soybean [Glycine max (L.) Merr.], known as edamame, needs weed management tools. Releasing locally adapted edamame soybean varieties and registering herbicides are necessary for successful production and expanding the edamame industry. This research aimed to 1) identify herbicides labeled for grain soybean for potential use on edamame; 2) evaluate differential tolerance of edamame soybean varieties to selected grain soybean herbicides; and 3) identify a feasible edamame-based crop rotation system. For objective 1, 26 herbicide treatments were tested on AVS-4002 edamame including preplant (PPL), preemergence (PRE) and postemergence (POST) herbicides labeled for grain soybean. Preplant herbicides caused 9 to 28% …

Evaluation And Characterization Of Fitness Costs In Multiple Herbicide Resistant Echinochloa In Arkansas, Teal Marie Penka

Graduate Theses and Dissertations

Echinochloa spp. are major weed problems for rice (Oryza sativa L.) on a global scale. In the southern rice belt of the U.S.A., Echinochloa colona (L.) Link (junglerice) and E. crus-galli (L.) P. Beauv (barnyardgrass) are the most troublesome weeds. These species are morphologically diverse, and its high ploidy level augurs high genetic diversity, which favors high adaptability to stress, including herbicide selection pressure. The objectives of these studies were to 1) isolate resistant (R) and sensitive (S) biotypes from eight accessions of E. colona with different resistance profiles; 2) determine the resistance levels of selected R and S biotypes …

Soybean Response To Dicamba: Associated Injury Criteria And Development Of A Model To Predict Yield Loss, Matthew Ryan Foster

LSU Doctoral Dissertations

In research conducted using indeterminate soybean [Glycine max (L.) Merr.], fourteen injury criteria observed following dicamba at 0.6 to 280 g ae ha^-1 (1/1000 to ½ of 560 g ha^-1 use rate) were rated using a scale of 0= no injury, 1= slight, 2= slight to moderate, 3= moderate, 4= moderate to severe, and 5= severe. Greatest crop injury 15 d after treatment (DAT) was observed following dicamba applied at 0.6 to 4.4 g ha^-1 at V3/V4 for upper canopy pale leaf margins (3.8 to 4.2) and at R1/R2 for terminal leaf cupping (4.1 to 5.0) …

Grains, Seeds And Hay Industry Funding Scheme Annual Report 2017/2018, Department Of Primary Industries And Regional Development, Western Australia

Biosecurity published reports

The Grains, Seeds and Hay Industry Funding Scheme (IFS) has been operating since 2010 to address biosecurity threats relevant to Western Australia’s (WA) grains, seeds and hay industry. The Scheme was established under the Biosecurity and Agriculture Management Act 2007 to enable growers to identify the pest and disease priorities at a whole-of-industry level and raise funds for activities to address these priorities.

There are currently three Industry Funding Schemes in operation. In addition to the Grains, Seeds and Hay IFS, there is a Cattle IFS and a Sheep and Goat IFS. The three IFSs operate in a similar manner. …

Perma/Culture: Imagining Alternatives In An Age Of Crisis By Molly Wallace And David Carruthers, Bryant Scott

The Goose

Review of Molly Wallace and David Carruthers' Perma/Culture: Imagining Alternatives in an Age of Crisis.

Managing Herbicide Resistance: Listening To The Perspectives Of Practitioners. Procedures For Conducting Listening Sessions And An Evaluation Of The Process, Jill Schroeder, Michael Barrett, David R. Shaw, Amy B. Asmus, Harold Coble, David Ervin, Raymond A. Jussaume Jr., Micheal D. K. Owen, Ian Burke, Cody F. Creech, A. Stanley Culpepper, William S. Curran, Darrin M. Dodds, Todd A. Gaines, Jeffrey L. Gunsolus, Bradley D. Hanson, Prashant Jha, Annie E. Klodd, Andrew R. Kniss, Ramon G. Leon, Sandra Mcdonald, Don W. Morishita, Brian J. Schutte, Christy L. Sprague, Phillip W. Stahlman, Larry E. Steckel, Mark J. Vangessel

Plant and Soil Sciences Faculty Publications

Seven half-day regional listening sessions were held between December 2016 and April 2017 with groups of diverse stakeholders on the issues and potential solutions for herbicide-resistance management. The objective of the listening sessions was to connect with stakeholders and hear their challenges and recommendations for addressing herbicide resistance. The coordinating team hired Strategic Conservation Solutions, LLC, to facilitate all the sessions. They and the coordinating team used in-person meetings, teleconferences, and email to communicate and coordinate the activities leading up to each regional listening session. The agenda was the same across all sessions and included small-group discussions followed by reporting …

Band-Sowing With Hoeing For Weed Management In Organic Grains, Margaret R. Mccollough

Electronic Theses and Dissertations

Weeds remain the foremost production challenge for organic small grain growers in the Northeastern United States. Instead of sowing crops in narrow, single-line rows, band-sowing with inter-band hoeing is a cropping strategy that could provide superior weed control. In theory, band-sowing suppresses weeds in the intra-band zone by improving the spatial arrangement of the crop from that of typical rows to a more uniform pattern within the planted bands, maximizing interspecific and reducing intraspecific competition. Weeds in the inter-band zone are controlled by cultivating with aggressive sweeps; tine harrowing can target weeds in the intra- and inter-band zones.

Chapter one …

Evaluation Of Acetochlor And Other Very-Long-Chain Fatty Acid-Inhibiting Herbicides In Arkansas Rice, Michael E. Fogleman

Graduate Theses and Dissertations

The prevalence of herbicide resistance and lack of effective management options for controlling problematic weeds such as barnyardgrass and weedy rice in Arkansas rice production has led to exploration of alternative herbicide sites of action (SOA). Very-long-chain fatty acid (VLCFA)-inhibiting herbicides are not currently labeled for use in U.S. rice production but have been used with success in other row crops and in rice production in Asia. Based on preliminary research, rice tolerance and weed control were evaluated following various application timings and rates of acetochlor and pethoxamid, in addition to several other VLCFA-inhibiting herbicides. Rice tolerance to acetochlor was …

Bedstraw Eradication Program: Annual Report To Grain Growers 2017/2018, Department Of Primary Industries And Regional Development, Western Australia

Biosecurity published reports

The Grains, Seeds and Hay Industry Management Committee (GSHIMC) believes the current program is delivering the best value for the funding provided and is achieving the project outcomes of containment and eradication.

Approved programs are developed annually for each infested property in consultation with GSHIMC, the Department of Primary Industries and Regional Development (DPIRD) and the landholders detailing management actions, estimated costs and timeframes of the agreed actions.

The two infested properties have now entered the final Release Phase of a nine year eradication program. The program is implemented by DPIRD and includes six consecutive years of winter spray treatments, …

Skeleton Weed Program: Annual Report To Grain Growers 2017/2018, Department Of Primary Industries And Regional Development, Western Australia

Biosecurity published reports

The Grains, Seeds and Hay Industry Management Committee (GSHIMC) believes the current program is delivering the best value for the funding provided and is achieving the Project Outcomes of eradication (where possible), management (on infested sites), and limiting the spread of Skeleton weed across the cereal growing districts.

There has been a significant increase in the infested area of Skeleton weed in 2017/18. Most of this increase was in the eastern zone where wet conditions favoured Skeleton weed in late 2017.

Many landholders in these areas also had difficulty achieving “long term” control over summer and infested areas needed monitoring …

Nitrogen And Weed Management In Transplanted Tomato In The Nigerian Forest-Savanna Transition Zone, J. A. Adigun, O. S. Daramola, O. R. Adeyemi, P. M. Olorunmaiye, O. A. Osipitan

Haskell Agricultural Laboratory (Northeast Research and Extension Center)

Weed infestation and inherent low soil fertility are among primary reasons for low yields of tomato in Nigeria. Field trials were carried out during the wet season of 2015 and 2016 to evaluate yield response of tomato to nitrogen (N) application and weed control methods in the forest-savanna transition zone of Abeokuta, Nigeria. Positive relationship exists between growth of weed species and increase in N application. Across the years of study, increase in N up to 90 kg/ha increased weed density by 11–25%, however, the increased N gave the transplanted tomato competitive advantage and thus enhanced weed smothering. Pre-transplant application …

Combinations Of Allelopathic Crop Extracts Reduce Digitaria Spp. And Setaria Faberi Seed Germination, Peter Apicella, Karl Guillard

Honors Scholar Theses

Allelopathic cover crops contain compounds that deter other types of plant seeds from germinating or inhibiting established plants’ growth. Sunflower (Helianthus annuus, SF), buckwheat (Fagopyrum esculentum Moench, BW), sorghum-sudangrass (Sorghum × drummondii [Nees ex. Steud.] Millsp. & Chase, SSG), and winter rye (Secale cereale) are all known allelopathic cover crops. However, there is little information about the use of these allelopathic cover crops used together and their combined impact on weed seed germination. Laboratory bioassays were conducted to determine the effect of the aforementioned cover crops alone and in combinations in reducing the …

Influence Of Multispecies Interference Of Common Ragweed (Ambrosia Artemisiifolia L.) And Common Waterhemp (Amaranthus Rudis Sauer) On Soybean [Glycine Max (L.) Merr.] Growth And Yield Under Variable Water Supply In Nebraska, Koffi Badou Jeremie Kouame

Department of Agronomy and Horticulture: Dissertations, Theses, and Student Research

Common ragweed (Ambrosia artemisiifolia L.) and common waterhemp (Amaranthus rudis Sauer) are two problematic weeds for soybean producers in the United States. Both weeds have evolved resistance to many herbicides, including glyphosate. It is therefore essential to understand how these weeds in mixture impact soybean growth and yield and also how they deplete soil moisture in rainfed and irrigated cropping systems. The objectives of this research were to: (i) understand the influence of variable water supply on soybean yield loss in mixture with ragweed and waterhemp, (ii) quantify the influence of variable water supply on soybean growth in …

Reducing Tillage In Small-Scale Permanent Bed Organic Vegetable Production Systems, Jeremiah D. Vallotton

Electronic Theses and Dissertations

The response of field-grown vegetable crops to reduced tillage and mulching in permanent beds was evaluated through measuring crop yields, weed pressure, earthworm counts, and soil basal respiration. Two vegetable crops (“Bush Delicata” squash and “Farao” cabbage) were started in April and May of 2016 and 2017 respectively, transplanted in late June, and harvested on 15-Sep-2016 and 25-Aug-2017. Fruit number and weight of squash, and head weight and feeding damage of cabbage were measured. These results suggest that intensive tillage (8” rototill every year) can be successfully reduced to alternating years of shallow (2”) rototilling and a less intensive form …

Weed Presence Altered Biotic Stress And Light Signaling In Maize Even When Weeds Were Removed Early In The Critical Weed‐Free Period, David P. Horvath, Stephanie Bruggeman, Janet Moriles-Miller, James V. Anderson, Munevver Dogramaci, Brian E. Scheffler, Alvaro G. Hernandez, Michael E. Foley, Sharon Clay

Agronomy, Horticulture and Plant Science Faculty Publications

Weed presence early in the life cycle of maize (typically, from emergence through the 8 to 12 leaf growth stage) can reduce crop growth and yield and is known as the critical weed‐free period (CWFP). Even if weeds are removed during or just after the CWFP, crop growth and yield often are not recoverable. We compared transcriptome responses of field‐grown hybrid maize at V8 in two consecutive years among plants grown under weed‐free and two weed‐stressed conditions (weeds removed at V4 or present through V8) using RNAseq analysis techniques. Compared with weed‐free plant responses, physiological differences at V8 were identified …

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. …

Gene Flow From Single And Stacked Herbicide-Resistant Rice (Oryza Sativa): Modeling Occurrence Of Multiple Herbicide-Resistant Weedy Rice, Joseph Dauer, Andrew Hulting, Dale Carlson, Luke Mankin, John Harden, Carol Mallory-Smith

School of Natural Resources: Faculty Publications

Background: Provisia™ rice (PV), a non-genetically engineered (GE) quizalofop-resistant rice, will provide growers with an additional option for weed management to use in conjunction with Clearfield® rice (CL) production. Modeling compared the impact of stacking resistance traits versus single traits in rice on introgression of the resistance trait to weedy rice (also called red rice). Common weed management practices were applied to 2-, 3- and 4-year crop rotations, and resistant and multiple-resistant weedy rice seeds, seedlings and mature plants were tracked for 15 years.

Results: Two-year crop rotations resulted in resistant weedy rice after 2 years with abundant populations (exceeding …

Propelled Abrasive Grit For Weed Control In Organic Silage Corn, Mauricio Erazo-Barradas, Fran Forcella, Dan Humburg

Agronomy, Horticulture and Plant Science Faculty Publications

Weed management in organic farming requires many strategies to accomplish acceptable control and maintain crop yields. This 2-yr field study used air propelled abrasive grit for in-row weed control in organically certified silage corn (Zea mays L.). Corncob grit was applied as a single application at corn vegetative growth stages V1 (one true leaf; numbers correspond to number of true leaves at the corn vegetative stage), V3, or V5 (in 2013) and V3, V5, and V7 (in 2014) and in double and triple combinations at these stages. Between-row weed control was accomplished by flaming or cultivation after the last grit …

Naive Yearling Steers Consume Little Sericea Lespedeza In The Kansas Flint Hills, C. A. Sowers, J. D. Wolf, W. H. Fick, K C. Olson

Kansas Agricultural Experiment Station Research Reports

Objective:The objective of this study was to characterize diets selected by steers grazing sericea lespedeza (Lespedeza cuneata)-infested native tallgrass pastures.

Study Description:The experiment was conducted on eight native tallgrass pastures located in Woodson County, KS, at the Kansas State University Bessner Range Research Unit during the 2015 and 2016 growing season. Pastures were burned annually in April and stocked with yearling steers (n = 281/year; initial body weight = 582 ± 75 lb) at a relatively high stocking rate (2.7 acres/steer) from April 15 to July 15. Basal frequency of sericea lespedeza was 2.9 …

Comprehensive Control Of Sericea Lespedeza With Four Consecutive Years Of Prescribed Fire During Summer, J. A. Alexander, W. H. Fick, J. Lemmon, G. A. Gatson, K C. Olson

Kansas Agricultural Experiment Station Research Reports

Objective:The objective of this study was to evaluate the effects of annual prescribed burning applied during the growing season on vigor of sericea lespedeza (Lespedeza cuneata) infesting native tallgrass range.

Study Description:We burned nine fire-management units (14 ± 6 acres) at one of three prescribed-burning times: early spring (April 1), mid-summer (August 1), or late summer (September 1). Effects on sericea lespedeza were evaluated annually on July 10, October 10, and November 1.

The Bottom Line:Compared to traditional spring, dormant-season burning, burning during the summer months over four consecutive years resulted in …

Vida Alone And In Tank Mixtures For Spring Kochia Control In Fallow, R. S. Currie, P. W. Geier, G. W. Boyer, P. W. Stahlman

Kansas Agricultural Experiment Station Research Reports

No herbicide treatment provided more than 50% kochia control at Garden City, KS, or 80% kochia control at Hays after the first week of application. At Garden City, KS, treatments of Vida (pyraflufen) plus glyphosate and 2,4-D or dicamba, glyphosate alone, or glyphosate plus 2,4-D or dicamba provided greater than 89% kochia control. At Hays, glyphosate alone or with 2,4-D, and Vida plus dicamba alone or with glyphosate had greater than 85% control of kochia.

Sericea Lespedeza Control Strategies Differ In Their Impacts On Overall Range Health And Native Plant Species Composition, 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 effects of sericea lespedeza (Lespedeza cuneata) control strategies of late summer prescribed burning and fall her­bicide application on soil cover, native plant populations, and biological diversity.

Study Description:We established 16 individual units within an 80-acre native tallgrass pasture. Each unit was assigned to 1 of 4 treatments: control, spray only, burn only, or burn-plus-spray. Burn only and burn-plus-spray units were burned in early September. Spray only and burn-plus-spray units were sprayed with metsulfuron methyl (Escort XP, DuPont, Wilmington, DE) in late September. The change in …

Comparison Of Soil-Applied And Postemergence Herbicides With Multiple Sites Of Herbicidal Activity On Two Populations Of Herbicide-Resistant Palmer Amaranth In Kentucky, Nicholas J. Fleitz

Theses and Dissertations--Plant and Soil Sciences

With the introduction of herbicide resistant Palmer amaranth into Kentucky during the past 10 years there has been an increasing concern for effective control measures in grain production. Field trials were performed in 2016 and 2017 near Barlow and Paris, KY to determine efficacy of chemical control programs targeting herbicide resistant Palmer amaranth. Percent visual control, effects on plant density and plant height were measured in 2016 to determine treatment effectiveness. Treatments containing four different sites of herbicide activity achieved an average of 98% control. Treatments containing only 3, 2 or 1 site of activity only achieved 64%, 45% and …

Sericea Lespedeza Control From Growing-Season Prescribed Burning Causes No Collateral Damage To Non-Target Species, J. A. Alexander, W. H. Fick, J. Lemmon, G. A. Gatson, K C. Olson

Kansas Agricultural Experiment Station Research Reports

Objective:The objective of this study was to evaluate the effects of 4 consecutive years of prescribed fire applied to native tallgrass range in either April, August, or September on forage biomass production, soil cover, and basal plant cover.

Study Description:Nine fire-management units (14 ± 6 acres) were burned at 1 of 3 prescribed times: early spring (April 1), mid-summer (August 1), or late summer (September 1). Plant species composition and soil cover were assessed annually each July using a modified step-point technique.

The Bottom Line:Burning during the summer for 4 consecutive years resulted in …

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 …

Grazing Diets Of Mature Ewes In The Flint Hills Contain A Significant Proportion Of Sericea Lespedeza, C. A. Sowers, J. D. Wolf, W. H. Fick, K C. Olson

Kansas Agricultural Experiment Station Research Reports

Objective:The objective of this study was to characterize diets selected by sheep grazing sericea lespedeza (Lespedeza cuneata) infested native tallgrass pastures and contrast these diets to those of cattle grazing the same range earlier in the grazing season. Multi-species grazing may provide an additional tool to aid landholders in the control of sericea lespedeza compared to cattle grazing only.

Study Description:The study was conducted on 8 native tallgrass pastures grazed by more than 800 mature ewes. Pastures were infested with sericea lespedeza (basal frequency = 2.9 ± 2.43%) and stocked with yearling steers at a relatively …

Cattlemen's Day 2018, E. A. Boyle

Kansas Agricultural Experiment Station Research Reports

Full report, Cattlemen's Day 2018.

Palmer Amaranth Populations From Kansas With Multiple Resistance To Glyphosate, Chlorsulfuron, Mesotrione, And Atrazine, V. Kumar, P. W. Stahlman, G. Boyer

Kansas Agricultural Experiment Station Research Reports

Multiple herbicide-resistant (MHR) Palmer amaranth poses a serious management concern for growers across the United States. Since 2014, several Palmer amaranth populations with suspected resistance to most commonly used herbicides were collected in random field surveys across Kansas. This study aimed to characterize the resistance levels to glyphosate (EPSPS inhibitor), mesotrione (HPPD inhibitor), chlorsulfuron (ALS inhibitor), and atrazine (PS II inhibitor) in three suspected MHR Palmer amaranth populations (KW2, PR8, and BT12) compared to a known herbicide-susceptible (SUS) population. Dose-response studies revealed that PR8 and BT12 populations had 7- to 14-fold level resistance to glyphosate, and up to 12-fold level …