Plant Pathology Commons^™

Near-Infrared Spectroscopy Analysis Of The Nutrient Content Of Dairy Pastures, R C. Kellaway, C Stimson, R J. Tassell

IGC Proceedings (1977-2023)

Pasture samples from temperate and tropical species were collected before and after grazing, at regular intervals, on 3 dairy farms in New South Wales over a period of 3 years. All samples (n=693) were analysed on a near-infrared (NIR) spectrophotometer with a scanning monochromator. Subsets of samples selected for calibration and validation, were analysed by wet chemistry methods for estimated metabolisable energy (MID), crude protein (CP), organic matter (OM), acid-detergent fibre (ADF), Ca, P, Mg, K, Na, S, Cu, Mn and Zn. These data were used lo develop NIR equations using partial least squares analyses. Standard errors of laboratory analysis …

Influence Of Oxygen Leakage Through Stretch Film On Quality Of Round Bale Silage, P Lingvall, C M. Pettersson, P Wilhelmsson

IGC Proceedings (1977-2023)

The ensiling-process is based on anaerobic conditions. Therefore, it is important to get "air tight" parcels covering big-bale silage. Wrapping round bales wilh stretch film has improved silage quality, and reduced diy matter (OM) and energy losses. In this experiment we studied the influence of stretch film quality, film thickness, .storage temperature and storage place on fermentation, microbial growth/ and DM losses. Additionally, oxygen permeability of stretch film wrapped in 4 or 6 layers around artificial bales (metal) and DM losses was tested In a model. High storage temperature, low total film thickness and high film permeability to oxygen increased …

Diseases Of Cannabis Sativa And The Epidemiology And Molecular Diversity Of Neofusicoccum Parvum, Hannah V. Zima

Graduate Theses and Dissertations

Cannabis sativa has been an underutilized agricultural resource in the United States, largely due to federal regulations distinguishing marijuana from hemp. In 2018, Congress passed a Farm Bill, which defined hemp as C. sativa containing a tetrahydrocannabinol (THC) level of no more than 0.3%. As a result, commercial hemp production began in most states in 2019, including Arkansas, and was accompanied by numerous challenges like diseases and pests. The research on the epidemiology of diseases affecting C. sativa is limited, and understanding the pathogens is in its early stages in the U.S. For this study, an initial disease survey was …

Fungal Pathogen Control And Microbial Ecology: Insights From Soybean Seed Production, Samantha Rigo Segalin

Graduate Theses and Dissertations

This study evaluated the effects of planting date (PD), seed vigor, and chemical seed treatments on the plant stand and yield of two soybean cultivars with different maturity groups (MGs) across four locations in Arkansas from 2018 to 2021. Early planting in early May (early PD) led to higher plant stands and yields compared to late planting in early June (late PD). The interaction between planting date and cultivar was significant, with both cultivars showing higher plant stands on early planting dates. Seed vigor and seed treatment also significantly impacted plant populations; high-vigor seeds planted early resulted in better stands …

Survey Of Nematodes Associated With Strawberry In South Carolina And Evaluation Of Short-Term Heat Exposure On Nematode Reproduction Biology, Ivan A. Alarcon Mendoza

All Theses

Nematodes are a growing threat to the multi-billion-dollar strawberry industry in the US due to the lack of safe and effective management methods. Limited information on the distribution of nematodes in fumigated plasticulture strawberry fields further complicates their management. Additionally, climatic anomalies like rising soil temperatures and heat waves are occurring more often, and their impact on crop growth and nematode reproduction is not well understood. The current study was conducted with two main objectives: i) understand distribution and population densities of nematodes associated with plasticulture strawberry production in South Carolina, and ii) understand the impact of short-term high heat …

Virion Composition Of Wheat Streak Mosaic Virus (Wsmv) And Its Use As An Expression Vector, Sourav Pal

Department of Plant Pathology: Dissertations, Theses, and Student Research

Wheat (Triticum aestivum L.) is the principal cereal grown in the United States, whose production ranks third in the world. Bacterial leaf streak (BLS) disease caused by Xanthomonas translucens pv. undulosa (xtu) is an emerging threat to wheat production in the Great Plains region of the United States of America. In this study, we engineered sequences encoding several plant-based antimicrobial peptides (AMP) were engineered into the WSMV genome and examined their effect on BLS disease in wheat infected by WSMV harboring AMP sequences. Out of nine AMPs, wheat expressing Ace-AMP1, PDF13, TK-AMP-D1, and TK-AMP-D3 produced resistance against the …

Investigating The Etiology, Epidemiology, And Ecology Of Blackberry Yellow Vein Disease In South Carolina, Wanita Dantes

All Dissertations

Blackberry production is growing in popularity in the southeastern U.S. However, blackberry growers in this region report major problems with productivity and longevity due to viruses. First, the state of knowledge on blackberry yellow vein disease (BVYD) complex, associated with mixed infections of a diverse group of viruses, is discussed. Specific viruses associated with symptom types are unknown. Therefore, the etiology of BYVD is not fully understood, which makes BYVD diagnosis challenging. My research focused on improving BYVD diagnosis, etiology, and epidemiology. Second, I developed a farm-level diagnostic protocol to improve virus disease surveillance. High throughput sequencing detected 17 known …

The Impact Of Ectopic Expression Of A Plant Elicitor Peptide In Bacillus Subtilis On Nematode Resistance In Soybean Through Seed Treatment, Abeer Alnasrawi

Graduate Theses and Dissertations

Soybean (Glycine max) is the most beneficial legume crop because it is a source of protein as well as oil for humans and livestock. Soybean is the second most planted crop in the United States following corn and it is also the fourth planted crop worldwide. However, the soybean cyst nematode (Heterodera glycines, SCN) is the most damaging pest of soybean in the United States, accounting for more than twice as much yield loss as the following cause of yield loss in soybean. Therefore, there is a pressing need to develop alternative management strategies to control SCN infection in soybeans. …

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 …

Cherry Powdery Mildew In Utah, Marion Murray, Christina Lilligren, Megan Kast

All Current Publications

This fact sheet provides information on powdery mildew, a common problem in commercial tart and sweet cherry orchards in Utah and throughout the western U.S. Hosts, disease biology, symptoms and signs, and management are covered.

Economics - The Neglected Dimension Of Pasture Disease R&D, N D. Macleod

IGC Proceedings (1977-2023)

Pasture utilisation underpins a significant contribution of livestock industries to Australia’s economic well-being. Pasture disease represents a direct threat to these enterprises but the economic magnitude of this threat remains largely unknown as the contribution of agricultural economics to pasture disease R&D, management and policy making has been minimal to date. Some insights to explain this apparent neglect are highlighted and a suggestion is made for a multiple disciplinary approach to R&D.

The 'Pendulum Paradigm' - Trends In Nitrogen Fertilizer Use On Temperate Grass/ Clover Pastures, R J. Eckard, F R. Mckenzie, P A. Lane

IGC Proceedings (1977-2023)

Nitrogen fertiliser responses, on perennial ryegrass (Lolium perenne) / white clover (Trifolium repens) dominant pastures, are compared between sub-tropical South Africa and temperate Australia. The data highlight the similarity in inflection point of the response curve, while emphasising the influence of high residual soil N at lower N application rates. The propensity of communities to oscillate between extremes in terms of N fertiliser use on intensive pasture, or the ‘Pendulum Paradigm’ is discussed. Particular reference is made to the dramatic increase in N fertiliser use in dairy pasture of temperate Australia and New Zealand. Emphasis is …

Linking Grassland And Range National Goals With The Grazing Lands Conservation Initiative For National Benefit, David B. Hannaway, Walter F. Wedin, Gerald W. Evers

IGC Proceedings (1977-2023)

Grassland and Range National Goals (GRNGs) were developed to identify national research and education needs for these resources, both public and private. The Grazing Lands Conservation Initiative (GLCI) developed within the NRCS to address the need for technical assistance for the management of privately held grazing lands. These activities are complimentary and, when combined, will address the national need for research, education, and technical assistance leading to better management of grassland and range resources.

The Effect Of Grazing On Etiolated Regrowth In Eight Grass Species, H A. Lardner, S.B M. Wright, R.D H. Cohen

IGC Proceedings (1977-2023)

Grazing by herbivores affects grass species both morphologically and physiologically. A grazing study was conducted on an irrigated pasture near Outlook, Saskatchewan, Canada during the summers of 1991 and 1992 to determine etiolated regrowth after grazing of reed canarygrass (Phalaris arundinacea L.), slender wheatgrass (Elymus trachycaulus (Link) Gould ex Shinners subsp. trachycaulus), intermediate wheatgrass (Thinopyrum intermedium (Host) Barkw. & D.R. Dewey subsp. intermedium), orchardgrass (Dactylis glomerata L.), meadow bromegrass (Bromus beibersteinii Roem. & Schult.), smooth bromegrass (Bromus inermis Leyss.), tall fescue (Festuca arundinacea (Schreb.) Wimm.) and timothy (Phleum pratense L.) in …

A Vison Of The Future World Food Production And Implications For The Environment And Grasslands, Per Pinstrup Andersen, Rajul Pandya Lorch

IGC Proceedings (1977-2023)

Increases in world population, projected to rise to 8 billion by 2020, and the resultant demand for food places great pressure on our agricultural and aquacultural resources. Anxiety about the future is exacerbated by decreasing grain stocks. Production increases of many commodities are projected to be between 1 and 2% per annum and will generally be higher in developing than in developed countries. Cultivatable land area will increase in some areas of the world but not in others. To cope with these challenges, yield increases will be essential and the application of existing knowledge and technologies will not suffice. Accelerated …

Canada's Forage Resources, D Mccartney, P R. Horton

IGC Proceedings (1977-2023)

Canada is the second largest country in the world and stretches 5,500 km east to west and 4,600 km north to south. About 90% of Canada is uninhabited with 90% percent of the population living within 500 km of the Canadian-American border. About 60% of Canadians live in southern Ontario and Quebec. The grazing industry is located primarily in western Canada with British Columbia, Alberta, Saskatchewan and Manitoba having 84% of the national beef herd. Ontario and Quebec have 73% of the national dairy herd. The majority of harvested forage, dehydrated alfalfa and forage seed crops are grown in western …

Opening Ceremony Address By Chairman Of The Continuing Committee, T Nolan

IGC Proceedings (1977-2023)

Chairman and Vice-Chairman of the Board ofDirectors of the XVIII International Grassland Congress, Your Honour, Lieutenant Governor of the Province of Manitoba, Minister of Agriculture of the Province of Manitoba, Distinguished guests, members of the International Rangeland Congress, members of the International Grassland Congress, ladies and gentlemen. On behalf of the Continuing Committee, I am privileged to welcome you to the XVIII International Grassland Congress. What we will witness is the culmination of about six years of preparatory work by the Canadian Organising Committee and on your behalf! sincerely congratulate them for setting the basis for most interesting scientific and …

Closing Address: A Developing Country Perspective, Walter S. Alhassan

IGC Proceedings (1977-2023)

It is an honour to present this closing address for the XVIII International Grassland Congress and I do it on behalf of colleagues in Africa, Asia and South America. The thirty themes and over 800 papers presented reflect the growing complexity of our grasslands in shaping the general well-being of people on this planet. The XVIX Congress, to be held in Brazil in 2001, will move the frontiers of knowledge concerning sustainable use of grassland resources even further.

This address is being made from the perspective of developing countries that contain the majority of tropical pastures. This region of the …

Closing Address: The View From Outside, Allan Nation

IGC Proceedings (1977-2023)

Closing Address

The Xvii International Grassland Congress And Challenges For The Future Of Tropical Grasslands: A Developing Country Perspective, W S. Alhassan

IGC Proceedings (1977-2023)

All too soon we are to draw down the curtains on the XVIII International Grassland Congress and it is my pleasure and honour to contribute to the closing statements of this historic event, the first of its kind in Canada and one to bring us to the end of the present millennium as we as set the stage for the next. I do this on behalf of my colleagues in Africa, Asia and South America.

The thirty themes and the nearly 2000 technical presentations underscore the growing complexity of the role of our grasslands in shaping the general well-being of …