Weed Science Commons^™

Genetic Diversity In An Invasive Clonal Plant? A Historical And Contemporary Perspective, Elliot D. Weidow

University of New Orleans Theses and Dissertations

Introduced populations of Eichhornia crassipes (Pontederiaceae) possess extremely low levels of genetic diversity due to severe bottleneck events and clonal reproduction. While populations elsewhere have been well studied, North American populations of E. crassipes remain understudied. We used Amplified Fragment Length Polymorphism markers to assess genetic diversity and population structure in North American E. crassipes populations. Patterns of diversity over the past fifty years were analyzed using herbarium specimens. Furthermore, we sampled populations across the Gulf Coast of the United States throughout a year to determine contemporary genetic diversity and assess potential seasonal effects. Genetic diversity was found to be ...

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

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 ...

Mitigating Bioiversity Loss Of Native Plants, Jamie Ana Grigonis

Student Theses 2015-Present

Growing up harvesting from my own vegetable garden and going from nursery to nursery with my mother, it has been extremely evident that plant biodiversity is more than just privet along driveways and carnations in window boxes. Plant biodiversity is often overlooked but crucial to having a healthy and thriving environment. Without certain plants, our ecosystems will crumble and this needs to be addressed now while it’s still at a level we can grow from. In my internship I am working alongside the director of the Thain Family Forest at the New York Botanical Gardens in order to get ...

Non-Target-Site Based Tolerance To Herbicides In Amaranthus Palmeri, Reiofeli Algodon Salas-Perez

Theses and Dissertations

Palmer amaranth, one of the most aggressive and damaging broadleaf weeds in the USA, has evolved resistance to multiple herbicide modes of action. The overall objective of this research was to elucidate the mechanisms by which Palmer amaranth adapt to herbicide selection stress. This research aimed (1) to evaluate the efficacy of fomesafen, glufosinate, glyphosate and trifloxysulfuron to Amaranthus populations; (2) identify candidate genes for endowing tolerance to glufosinate; (3) investigate the involvement of non-target-site resistance (NTSR) mechanism in an ALS-resistant population; and (4) to examine the molecular basis of resistance to PPO inhibitors in Palmer amaranth populations from Arkansas ...

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

Theses, Dissertations, and Student Research in Agronomy and Horticulture

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 mixture with ...

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 germination rate of Digitaria spp. (crabgrass) and Setaria faberi ...

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 ...

Diversity Post-Wildfire Of Vegitabel Understory In Rocky Mountain Ponderosa Pine Woodland And Montane Sagebrush Steppe, Bryce Walker

Carroll College Student Undergraduate Research Festival

In Montana, big sagebrush steppe, montane sagebrush steppe and rocky mountain ponderosa pine woodland take up over 16% of Montana’s 380,832 km2 (16.45%). Studies have shown that habitats dominated by graminoids depend on species abundance and richness to regulate invasion (Tilman 1997). The invasion process can be facilitated by the removal of native perennial species and the accumulation of seed banks of invasive annual grasses (Melgoza et al. 1990). Wildfire can contribute to these factors. A wildfire near Big Saw-Mill Gulch on September 1st 2016 offers an opportunity to compare diversity and richness in burned areas compared ...

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 ...

Roadside Integrated Vegetation Management Bmps: Right Tool For The Right Job, Cheryl Daniels, Davey Resource Group, Inc.

Purdue Road School

Based on a 3-year ODOT IVM research project, lessons learned and techniques for innovative and adaptive IVM for diverse midwestern landscapes will be presented that can increase Indiana DOTs’ efficiency and cost-effectiveness and simultaneously improve worker safety, foster safe highway use, improve roadside aesthetics, and promote environmental stewardship.

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

Papers in Natural Resources

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 ...

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 excellent control of sericea ...

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 treatment application and ...

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 soil cover and ...

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 ± 2.43 ...

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 high stocking ...

Herbicide And Application Timing Effects On Windmillgrass Control, Nicholas Mitchell, Jared Hoyle

Kansas Agricultural Experiment Station Research Reports

Windmillgrass (Chloris verticillata Nutt.) populations commonly infest turfgrass systems in the midwest, which result in aesthetically unacceptable turfgrass stands. Research trials were initiated in 2017 in Onaga and Junction City, KS, to determine windmillgrass control with various single herbicide applications at multiple application timings (spring, summer, and fall). Data collection for research trials consisted of visual percent windmillgrass cover (0–100%), line intersect analysis on four-inch spacing, normalized difference vegetation index (NDVI) (0 to 1 scale), and windmillgrass seedhead counts. Initial observations resulted in greater windmillgrass control with summer applications compared to fall applications. Pylex (topramezome) resulted in 80% windmillgrass ...

Cattlemen's Day 2018, E. A. Boyle

Kansas Agricultural Experiment Station Research Reports

Full report, Cattlemen's Day 2018.

Variable Response Of Kochia Accessions To Dicamba And Fluroxypyr In Western Kansas, V. Kumar, P. W. Stahlman, R. Currie, R. Engel, G. Boyer

Kansas Agricultural Experiment Station Research Reports

The rapid development of glyphosate resistance in kochia has increased the use of auxinic herbicides (dicamba and fluroxypyr) in the US Great Plains, including Kansas. Increasing reliance on auxinic herbicides for controlling glyphosate-resistant (GR) kochia may also enhance the evolution of resistance to these herbicide chemistries. The main objectives of this research were to (1) investigate the variation in kochia response to dicamba and fluroxypyr, and (2) characterize the dicamba resistance levels among progeny of kochia accessions collected from western Kansas. Greenhouse experiments were conducted at the Kansas State University Agricultural Research Center near Hays, KS. Discriminate-dose studies with field-use ...