Weed Science Commons^™

Species Diversity And Functional Composition Of Pastures That Vary In Landscape Position And Grazing Management, John A. Guretzky, Kenneth J. Moore, E. Charles Brummer, C. Lee Burras

C. Lee Burras

The productivity of grasslands depends in part on their diversity of species and functional composition. Our objective was to examine the effects of three landscape positions (summit, backslope, and toeslope) and three stocking systems (continuous, rotational, and nongrazed) on species diversity and percentage of cover of grass, legume, and weed species functional types in southeastern Iowa pastures. Data were collected in 0.2-m2 plots randomly distributed throughout each of four replicate pastures in spring and summer 2000 and 2001. Backslope landscape positions within pastures managed with either continuous or rotational stocking contained the greatest overall diversity of species. Across years ...

The Effects Of Isoprene Emission From Native And Invasive Trees On Local Air Quality, Aarti P. Mistry

DePaul Discoveries

Biogenic volatile organic compounds (BVOC) are the second-most abundant reactive gasses emitted into the atmosphere by the biosphere. Isoprene is a BVOC produced by the process of photosynthesis from vegetation and is emitted from plant leaves. Isoprene is a hydrocarbon that combines with oxides of nitrogen in the atmosphere to create ozone in the troposphere, an air pollutant. Invasive trees alter ecosystems and affect native tree populations. Invasive tree species in the Chicagoland area are outcompeting native tree species and expanding rapidly. The effect of isoprene emissions on air quality is a well-researched area in the atmospheric science community, however ...

Palmer Amaranth (Amaranthus Palmeri) Suppression With Half Rates Of Dicamba And Atrazine With Increasing Sorghum (Sorghum Bicolor) Density And Nitrogen Rate, I. B. Cuvaca, R. Currie, A. J. Foster

Kansas Agricultural Experiment Station Research Reports

Palmer amaranth (PA) competition can result in severe yield loss in grain sorghum. Increasing sorghum density and nutrient supply could promote early/rapid canopy closure and therefore reduce the amount of light that could otherwise penetrate the canopy and promote PA growth in sorghum. A study was conducted at the Southwest Research-Extension Center near Garden City, KS, to determine if PA could be suppressed with dicamba and atrazine applied as PRE at half rates combined with increasing sorghum density (60,000, 90,000, and 120,000 seeds/a), and nitrogen rate (0, 100, 200 lb/a). Preliminary results indicate that ...

Size-Dependent Patterns Of Reproductive Investment In The North American Invasive Plant Species Triadica Sebifera (L.) Small (Euphorbiaceae), Courtney H. Babin

University of New Orleans Theses and Dissertations

Knowledge of sex allocation trade-offs with tree growth in insect-pollinated woody plants is limited, particularly in invasive plants. This study examined patterns of growth and reproductive investment in a North American invasive plant species, Triadica sebifera, I hypothesized that the energy limitations of smaller trees may result in the production of more male reproductive structures that are energetically less costly. Diameter at breast height was a significant predictor of seed and catkin mass and regression can describe these relationships across sites. Seed and catkin mass were positively correlated across sites. The relationship between the seed mass:catkin mass ratio and ...

Evaluation Of Benzobicyclon For Use In Midsouthern Rice (Oryza Sativa) Systems, Mason Luke Young

Theses and Dissertations

A new herbicide site of action (SOA) is needed by rice (Oryza sativa L.) producers in the Midsouth for the control of problematic and herbicide-resistant weeds. Currently, six problematic weeds are relevant to Midsouthern rice producers because of resistance to at least one SOA, if not more. Gowan Company is in the process of commercializing benzobicyclon for use in Midsouthern rice systems. Benzobicyclon, a Group 27 post-flood herbicide, controls a broad spectrum of aquatics, broadleaves, grasses, and sedges, including those currently resistant to Group 2 herbicides. This will be the first 4-hydroxyphenylpyruvate dioxygenase (HPPD)-inhibiting herbicide commercially available in US ...

The Effect Of Spray Parameters On The Application Of Enlist Duo, Matthew R. Nelson

Theses, Dissertations, and Student Research in Agronomy and Horticulture

The emergence of new weed control challenges, along with shifts in weed management strategies and cultural practices, has resulted in an increased reliance on chemical weed control in United States (US) cropping systems. As a result, numerous weed species have evolved resistance to herbicides such as glyphosate, thus prompting the development of new weed control systems designed to aid growers in managing resistant weeds. While these new weed control options may give growers additional management options, the high sensitivity of broadleaf crops, fruits, and vegetables to products containing 2,4-D or dicamba increases the potential for herbicide drift resulting from ...

Value Of Cover Crops In Suppressing Weeds And Protecting Cotton Yields And Likelihood Of Residual Herbicide Carryover To Cover Crops, Matheus Gabriel Palhano

Theses and Dissertations

Weed-resistance management has become a topic of concern for modern agriculture. Cost related to herbicide usage has increased greatly due to evolution and proliferation of resistant weeds. Therefore, experiments were conducted to investigate the potential for using cover crops to suppress problematic weeds in cotton as well as chemical options for cover crop dessication, and sensitivity of cover crops to residual herbicides were evaluated. No differences were observed for cereal rye biomass production and consequently weed suppression between broadcast and drilled planting methods. Total amount of cover crop biomass was vital to effectively suppress weeds. Hence, of the cover crops ...

Evaluation Of Safening Effects To Herbicides Conferred Via Insecticide Seed Treatments In Soybean (Glycine Max) And Grain Sorghum (Sorghum Bicolor), Nicholas Robert Steppig

Theses and Dissertations

Interactions between herbicides and insecticides in crop production have been documented for a number of years. Research has shown that applications of some organophosphate insecticides at planting can reduce cotton injury following applications of the soil-applied herbicide clomazone. Additionally, recent research has shown that, when applied as seed treatments prior to planting, some neonicotinoid insecticides can safen rice to drift from both glyphosate and imazethapyr. Since insecticide seed treatments are commonly used in many crop production systems throughout the Midsouth, exploring their ability to reduce injury from herbicides in other crops besides rice is of great interest. Presently no research ...

Decision Support Software For Palmer Amaranth Weed Control, Karen Renee Lindsay

Theses and Dissertations

Herbicide-resistant Palmer amaranth [Amaranthus palmeri (S.) Wats.] has been identified as one of the most troublesome weeds, specifically for corn (Zea mays L.), cotton (Gossypium hirsutum L.), and soybean [Glycine max (L.) Merr.] producers in the southern United States. The use of herbicide technology remains the most widely used method of weed control, despite the evolution of herbicide-resistant Palmer amaranth. Therefore, a need currently exists for research and extension education to encourage the adoption of Integrated Pest Management (IPM) to address the problem of herbicide-resistant Palmer amaranth in the southern United States. By equipping crop producers, educators, and weed management ...

The Extent To Which Weeds Modify The Transpiration Of Cereals, A. L. Bakker, H. H. Plagge

Research Bulletin (Iowa Agriculture and Home Economics Experiment Station)

This work on transpiration involved a study of the competition and the comparison of the growth of wheat, of wheat with mustard, of oats alone and oats with mustard. To determine the growth and development taking place in the various cultures, measurements were made at frequent intervals of the increases in leaf area and of the amount of water lost. The data clearly show that weeds require a large amount of water.

Comparing the pure and mixed cultures leaves no doubt but that a weed like mustard impairs the crop. The effect is evidenced in the fact that a culture ...

North American Continent - A New Source Of Wild Lactuca Spp. Germplasm Variability For Future Lettuce Breeding, A. Lebeda, I. Doležalová, M. Kitner, A. Novotná, P. Šmachová, M. P. Widrlechner

Mark P. Widrlechner

In the years 2002-2008, missions were undertaken in the USA and Canada to search for wild and weedy Lactuca species. Altogether, 16 states in the USA (Arizona, California, Colorado, Idaho, Iowa, Minnesota, Montana, Nevada, New York, North Carolina, Oregon, South Dakota, Utah, Washington, Wisconsin and Wyoming) and two provinces in Canada (Ontario and Quebec) were visited. In total, seven wild and weedy Lactuca spp. (L. serriola, L. saligna, L. virosa, L. canadensis, L. biennis, L. floridana, and L. ludoviciana), an interspecific hybrid (L. canadensis × L. ludoviciana), and an undetermined Lactuca species were observed and collected in 200 locations. In this ...

Effects Of Growing-Season Prescribed Burning On Vigor Of Sericea Lespedeza In The Kansas Flint Hills: Ii. Plant-Species Composition, J. A. Alexander, W. H. Fick, J. Lemmon, G. A. Gatson, G. W. Preedy, K C. Olson

Kansas Agricultural Experiment Station Research Reports

Fire has, for centuries, been a key force for sustainability of native ecosystems in the Kansas Flint Hills. Prior to the arrival of European settlers, prescribed and wild fires occurred at less than 3-year intervals in the tallgrass prairie region. As a result, native tallgrass plant communities adapted to fire at regular intervals and plant-species composition became stable on a geologic time scale.
Currently, prescribed fire is used in the Kansas Flint Hills as a treatment for control of woody-stemmed invasive species such as eastern red cedar, honey locust, and roughleaf dogwood. These fires are generally applied in March and ...

Effects Of Growing-Season Prescribed Burning On Vigor Of Sericea Lespedeza In The Kansas Flint Hills: I. Suppression Of Seed Production And Canopy Dominance, J. A. Alexander, W. H. Fick, J. Lemmon, G. A. Gatson, G. W. Preedy, K C. Olson

Kansas Agricultural Experiment Station Research Reports

Sericea lespedeza (Lespedeza cuneata) is a highly fecund noxious weed in Kansas and surrounding states. Individual plants are capable of producing greater than 1,000 seeds annually. Vigorous seed production allows sericea lespedeza to rapidly infiltrate native and cultivated grasslands; seed can be transported great distances via farm machinery and the alimentary canal of wild and domestic herbivores. In Kansas alone, sericea lespedeza infests more than 700 square miles of pasture, primarily in the Flint Hills region. The resulting damage to native habitats for wildlife and pasture quality for domestic herbivores has been devastating.
The predominant grazing management practice in ...

Warm Fall Temperatures, Scn And Winter Annual Weeds, Gregory L. Tylka

Gregory Tylka

We have had a wonderfully sunny, warm, dry fall so far this year. How could anyone complain about the weather? Leave it to a nematologist. Yesterday's ICM News article reminded growers and agronomists to delay application of anhydrous ammonia fertilizer until soil temperatures drop below 50F. It turns out that 50F is also an important temperature to consider for soybean cyst nematode (SCN).

Invasion Dynamics Of The Exotic Liana Euonymus Fortunei (Turcz.) Hand.-Mazz. (Wintercreeper), Todd J. Rounsaville

Theses and Dissertations--Biology

Elevated atmospheric CO₂ has been implicated as a driver of increased liana abundance worldwide. Known as disturbance creators and beneficiaries, lianas possess the potential to significantly influence forest ecosystems. I investigated the early-invasion dynamics of Euonymus fortunei (wintercreeper), an evergreen liana that is invading forests in eastern North America, disrupting native plant communities and ecosystem functions.

Wintercreeper is widely cultivated as an ornamental groundcover, frequently invading natural areas via asexual stem growth. Invasion of remote natural areas is dependent upon seed transport and may occur less frequently. I examined the mechanisms of seed dormancy by conducting a ‘move-along’ experiment ...

Evaluation Of New Sweet Corn Herbicides, Vince Lawson

Farm Progress Reports

Current weed control recommendations rely heavily on the use of multiple herbicide groups for broad spectrum weed control and preventing development of herbicide resistant weeds. Sweet corn growers, as compared with other specialty crop growers, are fortunate in this regard as they have a fairly diverse and growing list of herbicides from which to choose. Recently, the herbicides Acuron and Acuron Flexi from Syngenta, Anthem and Anthem Maxx from FMC, and Revulon Q from Dupont were approved for use in sweet corn. Ingredients in these products represent five different herbicide groups (HG). The purpose of this trial was to evaluate ...

Evaluation Of Select Herbicides On Non-Bearing Crops, Diane Cochran, Kenny Mccabe

Farm Progress Reports

This study was conducted as part of the IR-4 Project to investigate herbicide phytotoxicity on two growth stages of northern pecan (Carya illinoensis), Spanish chestnut (Castanea sativa), Montmorency cherry (Prunus Montmorency), and black chokeberry (Photinia melanocarpa).

Two-Pass Herbicide Programs For Weed Control In Corn, Micheal Owen, Damian Franzenburg, James Lee, Iththiphonh Macvilay

Farm Progress Reports

The purpose of this study was to evaluate various herbicides applied preemergence and postemergence in corn for crop injury and weed control.

Does Timing Of Herbicide Use Influence Rates Of Germination Or Seedling Biomass Of Native Plants Used For Restoration?, Christine Mcmanamen

Graduate Student Theses, Dissertations, & Professional Papers

Invasive plants can negatively impact native grasslands by changing their species composition, productivity, and function. Managers commonly use herbicides as a control method; however, this practice can lead to secondary invasion by other non-native invasive plants, unless measures are taken to promote natives. Because of this, managers often seed native plants after spraying herbicides. There is evidence, however, that chemical control of invasive plants may reduce the effectiveness of subsequent seed-addition treatments, but there is currently little quantitative information on optimal timing between spraying and seeding or on variation in herbicide sensitivity among native plants commonly used in seed mixes ...

Drivers And Feedbacks Of The Fire-Grazing Interaction In The Northern Great Plains, Jacob E. Powell

Graduate Student Theses, Dissertations, & Professional Papers

The fire-grazing interaction is well studied in mesic grasslands worldwide, but research is lacking in semiarid systems. In addition, the fire-grazing interaction reduces the invasion of exotic forage species in mesic grasslands by increasing the scale of grazing selection and may be a tool to control invasive plants in other grasslands. We examined the principal drivers and feedbacks of the fire-grazing interaction on the strength of cattle grazing selection, forage quantity and quality, and vegetation structure and composition in two pastures in northeast Montana at The Nature Conservancy’s Matador Ranch. We also determined the influence of time since fire ...