Plant Pathology Commons^™

Fungicide Sensitivity In P. Tritici-Repentis Diverse Population And Phenotyping Of Spelt Wheat For Multiple Diseases, Zunera Shabbir

Electronic Theses and Dissertations

Pyraclostrobin, a QoI fungicide, is extensively used in the management of fungal leaf spot diseases. In this study, 215 P. tritici-repentis isolates collected from wheat fields in South Dakota were evaluated for their sensitivity to Pyraclostrobin. Of 215 isolates, 48 isolates (22%) exhibited insensitivity based on G143A mutation and EC50 values using spore germination assay. Our results indicate reduced sensitivity to insensitivity to pyraclostrobin in some isolates suggesting regular monitoring of the P. tritici-repentis population to QoI fungicides is essential to track the evolution of insensitive population. Spelt wheat (Triticum spelta L.) is an ancient cereal that is gaining small …

The Effects Of Residue Amounts And Variety Selection On The Development Of Wheat Fungal Pathogens In South Dakota, Abrielle Tembreull

Electronic Theses and Dissertations

Roughly 50% of South Dakota cropland is under the practice of no-till, with large increases in acres of no-till in the last 20 or so years. No-till is beneficial for Great Plains states, such as South Dakota, as soil residues are withheld. Residues are shown to increase soil health through retention of moisture and increase of microorganisms, but residues can serve as a source of inoculum for fungal pathogens that can overwinter on them. As wheat is one of the most important food crops in the world, it is important to protect this vital crop from diseases. Diseases of wheat …

Fusarium Head Blight Resistance Assessment In Barley, Tasneem Fathima

Electronic Theses and Dissertations

Fusarium head blight (FHB), commonly called scab is the most devastating disease of wheat and barley caused by the ascomycete fungus, Fusarium graminearum. FHB affects both the quality and quantity of cereal grains affecting the supply chain of the food and feed industry and the marketability of the produce. Barley (Hordeum vulgare L.) is among the several crop species most vulnerable to FHB infection. An estimated 25% of Spring barley grain production in the United States is used to make malted beverages such as beer. Malting barley is a relatively high-value crop with high demands regarding grain quality. FHB directly …

Effect Of Essential Oils In The Control Of Fungal Diseases In Small Grains, Esneider Mahecha Bojaca

Electronic Theses and Dissertations

Spring wheat (Triticum aestivum L.) and oats (Avena sativa L.) are important crops due to their high consumption in our daily diet worldwide. They are the main food of consumption per capita due to the high amino-acid content as well of vitamins. However, grain production is limited due to the negative impact of the diseases that cause significant yield loss. Diseases in oats, such as crown rust caused by Puccinia coronata f. sp. avenae (Pca), and in wheat such as Fusarium head blight (FHB) caused by the fungus Fusarium graminearum. Foliar diseases such as tan spot incited by the fungi …

Efficacy Of Nanomaterials And Biorationals On The Bacterial Leaf Streak Management In Wheat, Abraham Hangamaisho

Electronic Theses and Dissertations

Wheat (Triticum aestivum L.) is one of the most important cereal crops in the United States. Most wheat varieties are susceptible to bacterial leaf streak (BLS), a major disease caused by Xanthomonas translucens pv. undulosa (Xtpvu). BLS is challenging to manage since common chemicals do not provide adequate control. Nanomaterials and plant extracts have shown potential to provide a sustainable environmentally friendly control of animal and plant diseases. However, limited data are available on the efficacy of plant extracts and nanomaterials controlling BLS in wheat. The objective of this study was to evaluate the antibacterial activity of plant extracts and …

Evaluating Fungicide Timing, Efficacy, And Sensitivity As Well As Candidate Resistance Genes Against Fungi Causing Phomopsis Stem Canker In Sunflower, Ruchika Kashyap

Electronic Theses and Dissertations

Phomopsis stem canker is one of the major diseases of sunflower (Helianthus annuus L.) caused by complex of Diaporthe spp., in the U.S. This disease became of economic importance after 2010 epidemic in Minnesota, North Dakota, and South Dakota and since then the prevalence of this diseases has increased due to increased average precipitation in these major sunflower growing regions of the U.S. The two important disease management strategies involve the use of fungicides and partially resistant hybrids. However, over the years, researchers and growers have seen varied results on Phomopsis stem canker disease severity reduction and yield gains, when …

Phomopsis Stem Canker Of Sunflower (Helianthus Annuus L.): Etiology And Epidemiological Conditions Affecting Endophytic Population Of Diaporthe Spp., And Fungicide Efficacy, Nabin Kumar Dangal

Electronic Theses and Dissertations

Phomopsis stem canker (PSC), caused by species of Diaporthe, is a major disease of sunflower (Helianthus annuus L.) in the U.S., which can cause yield loss over 40%. The disease prevalence increased since 2010 in the major sunflower producing U.S. states of Nebraska, Minnesota, North Dakota, and South Dakota. Previous studies on the use of foliar fungicides in managing Phomopsis stem canker indicated mixed results on their efficacy in disease reduction and yield gain. Additionally, we do not have sufficient information on asymptomatic colonization by endophytic Diaporthe on sunflower tissue and how foliar fungicide and weather parameters affect the prevalence …

Evaluating The Current Weed Community In Wild Blueberry Fields And Ipm Strategies For Spreading Dogbane (Apocynum Androsaemifolium), Anthony G. Ayers

Electronic Theses and Dissertations

Lowbush blueberry (Vaccinium angustifolium) is Maine’s third largest crop (USDA 2020 a). From 2017 – 2019 the three seasons yield average was 27,200 tons were harvested from 19,500 acres for a value of $22,468,000 (USDA 2020 c). Lowbush blueberries are managed on a two-year cycle. Every other year, lowbush blueberry fields are pruned to the ground either through the use of a tractor mounted flail mower or a prescribed burn (Yarborough 2009). Pruning is a necessary part of managing lowbush blueberries as the second-year growth produces the highest yield but steadily declines in subsequent years (Drummond et al. …

Determining The Effects Of Plant Extracts And Saltro Nematicide On Hatching, Mortality And Reproduction Of The Soybean Cyst Nematode (Heterodera Glycines), Bishnu Prasad Dhital

Electronic Theses and Dissertations

Soybean cyst nematode (SCN) is a microscopic worm that infects and feeds from the soybean roots, hence robbing the plant of nutrients, and entry wounds may facilitate other pathogens to infect the roots. Current SCN management practices include cultural, chemical, and biological methods. Cultural practices such as, crop rotation with non-host and different tillage practices are not efficient due to the persistent nature of SCN in the soil. Chemical nematicides, though effective, can be expensive, and some are not environmentally sound. SCN resistant soybean varieties are mainly derived from one source, PI 88788 and SCN population have already evolved to …

Characterizing Spatiotemporal Patterns Of White Mold In Soybean Across South Dakota Using Remote Sensing, Confiance L. Mfuka

Electronic Theses and Dissertations

Soybean is among the most important crops, cultivated primarily for beans, which are used for food, feed, and biofuel. According to FAO, the United States was the biggest soybeans producer in 2016. The main soybean producing regions in the United States are the Corn Belt and the lower Mississippi Valley. Despite its importance, soybean production is reduced by several diseases, among which Sclerotinia stem rot, also known as white mold, a fungal disease that is caused by the fungus Sclerotinia sclerotiorum is among the top 10 soybean diseases. The disease may attack several plants and considerably reduce yield. According to …

Some Studies On Leaf Spot Of Oats And Triticale, Mohammed Abdullah Lashram

Electronic Theses and Dissertations

Oat is an important cereal crop, and it is considered to be among the highest used in cereal crops. It is considered among the healthiest grains due to the rich source of the soluble fiber, β-glucan that helps in lowering the cholesterol. Oat production and demand have increased considerably in the past few years due to its health benefits. South Dakota is ranked in the top three largest oat-producing states in the USA. Oat is relatively less susceptible to pest and diseases except for leaf diseases such as crown rust, Drechslera avenae leaf spot, and Stagonospora avenae leaf blotch. Leaf …

Species Of Fusarium Causing Root Rot Of Soybean In South Dakota: Characterization, Pathogenicity, And Interaction With Heterodera Glycines, Paul Nyawanda Okello

Electronic Theses and Dissertations

In South Dakota, Fusarium-associated diseases (e.g. seedling diseases, root rot and sudden death syndrome) are emerging threats to soybean production. Several species of Fusarium have been reported to cause these diseases in the soybean producing regions of the United States and in the world. However, little information is available on the species of Fusarium causing soybean root rot in South Dakota and their pathogenicity. Therefore, the objectives of this study were to (1) characterize the species of Fusarium causing soybean root rot in South Dakota; (2) evaluate the cross-pathogenicity of species of Fusarium causing root rot of soybean and corn; …

Efficacy Of Synthetic And Biopesticides On Bacteria Leaf Streak Management And Influence Of Cultivar And Environment On Epiphytic Bacteria Diversity On Wheat Seeds, Marilen Nampijja

Electronic Theses and Dissertations

Wheat (Triticum aestivum) is the most important staple food for over two billion people, or 36% of the world population. The United States ranks 4th in the world for wheat production. However, wheat production is faced by both biological and non-biological constraints. Among the biological constraints, diseases play a big role in limiting wheat production with estimated yield losses ranging from 20% to 40%. Bacterial leaf streak (BLS) of wheat caused by Xanthomonas translucens pv undulosa (Xtpvu) is one of the major bacterial diseases affecting the wheat production in most wheat growing regions in the USA. In recent years, it …

Efficacy Of Seed Treatments, Microbial And Biochemical Pesticides For Managing Early Tan Spot And Stripe Rust Diseases Of Wheat, Collins Bugingo

Electronic Theses and Dissertations

Wheat is a major cereal crop in the U.S.A and in the world. However, its production is hampered by a number of factors both biotic and abiotic. Foliar diseases like tan spot caused by Pyrenophora tritici-repentis and stripe rust caused by Puccinia striiformis f. sp. tritici, are economically important diseases causing over 5-55 % yield loss. To assess the efficacy of fungicide seed treatments in the management of early tan spot, two hard red spring wheat cultivars “Select” and “Brick” were treated with seedapplied commercially available combo fungicides metalaxyl + pyraclostrobin + triticonazole and difenoconazole + mefenoxam + sedaxane …

Molecular Characterization Of Spot Blotch And Bacterial Leaf Streak Resistance In Bread Wheat, Girma Ayana

Electronic Theses and Dissertations

Spot blotch (SB), caused by Bipolaris sorokiniana (Sacc.) Shoem, and bacterial leaf streak (BLS), caused by Xanthomonas translucens pv. undulosa (Smith et al.), two important foliar diseases of wheat in the major production regions of the US and the world. Deployment of adequate host resistance against them depends on determining the resistance genes or quantitative trait loci (QTLs) responsible for the trait and identification of genetic markers linked to QTL that facilitate markers assisted breeding. We conducted two independent studies and characterized QTLs for BLS and SB resistance. In the first study, we constructed a genetic linkage map of 1,211 …

Mitigating Risks Of Ochratoxin A Contamination In Oats, Bandana Dhungana

Electronic Theses and Dissertations

Ochratoxin A (OTA) is a toxic metabolite produced by several species of fungal genera Penicillium and Aspergillus. The major OTA producer in temperate regions (i.e. U.S., Canada, Europe) is Penicillium verrucosum. Oat (Avena sativa), like any other cereal grain, can be contaminated with OTA when storage conditions are favorable for fungal growth. The presence of OTA exceeding the European Union maximum limit of 3 ppb in processed food has been reported in some samples of oat-based breakfast cereals from the US. The use of oat genotypes with limited OTA accumulation would be an effective way to …

Characterization Of Pyrenophora Tritici-Repentis In Wheat And Rye To Study Tan Spot Susceptibility And Insights Into Its Relationship With Stem Rust Resistance, Sidrat Abdullah

Electronic Theses and Dissertations

Tan spot, caused by the ascomycete fungus, Pyrenophora tritici-repentis (Ptr), is a major foliar fungal disease of wheat worldwide. To date, Ptr isolates have been grouped into eight races based on the production of three host selective effectors (toxins), Ptr ToxA, ToxB, and ToxC, which are associated with necrosis and chlorosis symptoms on wheat differential lines. In order to see the correlation between stem rust resistance and tan spot susceptibility in 1970’s, to know the pathogen virulence profile, and explore the sources of tan spot resistance, we recovered isolates from wheat and rye and evaluated wheat and rye lines with …

Distribution And Characterization Of The Soybean Cyst Nematode, Heterodera Glycines (Hg) Types In South Dakota, Krishna Acharya

Electronic Theses and Dissertations

The soybean cyst nematode (SCN), Heterodera glycines Ichinohe, is an endoparasitic nematode and one of the major pests of soybean (Glycine max L.) in the United State and all over the world where soybean is grown. SCN is ranked first among the biological factors that cause yield loss in soybean. The estimated yield loss by this nematode is $1b annually in the United States alone. SCN is thought to have been first found in China. It was first identified in the United States in 1954 in North Carolina and in South Dakota in 1995. To date, SCN continues to spread …

A Study Of The Forage Plants Of South Dakota With Their Fungous And Insect Enemies, David Griffiths

Electronic Theses and Dissertations

The main object of this study being a better acquaintance with fungous parasites, the work on the host plants has been considerably abridged in order that the discussion might be shortened. It was the plan at first to include in this paper a carefully written description of each of the principal forage plants of the state. The futility of such a plan, however, soon became apparent, and it was accordingly decided to omit the description and include simply Distribution,

Habitat, Value as Forage, and the Fungous Parasites of each host. There are, therefore, several of our best forage plants omitted …