Plant Pathology Commons^™

Arkansas Soybean Research Studies 2024, Jeremy Ross

Arkansas Agricultural Experiment Station Research Series

The 2024 Arkansas Soybean Research Studies includes research reports on topics pertaining to soybean across several disciplines from breeding to post-harvest processing. Research reports contained in this publication may represent preliminary or only data from a single year or limited results; therefore, these results should not be used as a basis for long-term recommendations. Several research reports in this publication will appear in other University of Arkansas Division of Agriculture’s Arkansas Agricultural Experiment Station publications. This duplication is the result of the overlap in research coverage between disciplines and our effort to inform Arkansas soybean producers of the research being …

Fungicidal Management Of Spring Dead Spot Using Improved Modeling And Application Strategies, Michael Vincent Battaglia

Graduate Theses and Dissertations

Spring dead spot (SDS) is a destructive disease of bermudagrass (Cynodon Rich. spp.) in parts of the world that experience winter dormancy. Fungicides are often necessary to properly manage SDS, and significant research has been conducted to improve fungicidal effectiveness. Several studies were conducted with the objectives of improving fungicide application timing, method of fungicide application, and long-term fungicidal efficiency. In the fungicide application study, a cooling degree-day (CDD) model based on soil temperatures was developed. The CDD model showed that isofetamid was highly effective against SDS during a wide application window in autumn, while tebuconazole was inconsistently effective and …

Transgenerational Imprints Of Sequential Herbivory Onsoybean Physiology And Fitness Traits, Insha Shaft, Rupesh Kariyat

Entomology and Plant Pathology Faculty Publications and Presentations

Sequential herbivory leads to a multitude of effects on plants, influencing processes like growth, physiology, defense, and fitness. However, whether the sequential herbivore attack can elicit any transgenerational consequences is poorly examined. In this study, we show evidence of transgenerational impacts of sequential herbivory by two chewing herbivores, fall armyworm (Spodopterafrugiperda , FAW) and soybean looper (Chrysodeixis includens , SL) on soybean (Glycine max ) progeny. Seeds from the parents subjected to different herbivore sequences (SL-FAW: initial attack by SL followed by FAW and FAW-SL: FAW followed by SL) were used for the transgenerational experiment. Our main hypothesis was that …

Arkansas Corn And Grain Sorghum Research Studies 2024, Jason Kelley, Travis Faske

Arkansas Agricultural Experiment Station Research Series

The 2024 edition of the Arkansas Corn and Grain Sorghum Research Studies Series includes research results on topics pertaining to corn and grain sorghum production, including weed, disease, nematode, and insect management; economics; irrigation; agronomics; soil fertility; drone use; and research verification program results.

Our objective is to capture and broadly distribute the results of research projects funded by the Arkansas Corn and Grain Sorghum Board. The intended audience includes producers and their advisors, current investigators, and future researchers. The Series serves as a citable archive of research results.

The reports inform and guide our long-term recommendations, but should not …

Optimized Atmospheric Air Cold Plasma Seed Treatments Differentially Enhance Plant Growth And Herbivore Resistance In Soybean (Glycine Max) And Sorghum-Sudangrass (Sorghum X Drummondii), Deepak Dilip, Niitha Modupalli, Soumya Unnikrishnan, Mahfuzar Rahman, Rupesh Kariyat

Entomology and Plant Pathology Faculty Publications and Presentations

Atmospheric air cold plasma treatments (cold plasma; CP) have emerged as a promising technology in various fields, including medicine, agriculture, and environmental sciences. While CP treatment has been optimized in many fields, we lack empirical data on the efficiency and effectiveness of CP treatments in deterring insect herbivory, a recent development in CP application. Needless to say, by fine-tuning parameters such as plasma discharge method, exposure time, source gas, and input voltage, researchers can enhance the desired effects while minimizing any potential side effects. Reactive oxygen and nitrogen species (ROS and RNS) generated during CP treatments can potentially play a …

Arkansas Soybean Performance Tests 2024, J. F. Carlin, R. D. Bond, T. C. Swanson, J. C. Mccoy

Arkansas Agricultural Experiment Station Research Series

Soybean variety and strain performance tests are conducted each year in Arkansas by the University of Arkansas System Division of Agriculture’s Arkansas Crop Variety Improvement Program. The tests provide information to companies developing varieties and/ or marketing seed within the state and aid the Arkansas Cooperative Extension Service in formulating variety recommendations for soybean producers.

Arkansas Soybean Research Studies 2023, Jeremy Ross

Arkansas Agricultural Experiment Station Research Series

The 2023 Arkansas Soybean Research Studies includes research reports on topics pertaining to soybean across several disciplines from breeding to post-harvest processing. Research reports contained in this publication may represent preliminary or only data from a single year or limited results; therefore, these results should not be used as a basis for long-term recommendations.

Several research reports in this publication will appear in other University of Arkansas System Division of Agriculture’s Arkansas Agricultural Experiment Station publications. This duplication is the result of the overlap in research coverage between disciplines and our effort to inform Arkansas soybean producers of the research …

Advancing Molecular Tools For The Study Of Rubus Viruses, Andrea Sierra-Mejia

Graduate Theses and Dissertations

Since blackberry yellow vein disease (BYVD) was first described, the blackberry virome has expanded significantly. BYVD is a complex disease associated with over ten viruses, yet the role of each virus in its etiology remains understudied. Studying the effect of each virus in disease development requires the identification of single infections; however, this task has been difficult for BYVD, with all field collected material over the past two decades consistently found infected by multiple viruses. Given the diversity of viruses associated with the disease and their different modes of transmission, obtaining pure virus cultures necessitate transmission of individual viruses via …

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 …

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 …

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. …

Arkansas Corn And Grain Sorghum Research Studies 2023, Jason Kelley, Travis Faske

Arkansas Agricultural Experiment Station Research Series

The 2023 edition of the Arkansas Corn and Grain Sorghum Research Studies Series includes research results on topics pertaining to corn and grain sorghum production, including weed, disease, and insect management; economics; irrigation; agronomics; soil fertility; mycotoxins; cover crop management; and research verification program results. Our objective is to capture and broadly distribute the results of research projects funded by the Arkansas Corn and Grain Sorghum Board. The intended audience includes producers and their advisors, current investigators, and future researchers. The Series serves as a citable archive of research results.

Decomposition Of Bark Beetle-Attacked Trees After Mortality Varies Across Forests, N. A. Clay, J. D. Tang, C. M. Siegert, J. T. Thomason, N. Benedetto, D. Day, K. Pace, O. Leverón, R. W. Hofstetter, J. J. Riggins

Entomology and Plant Pathology Faculty Publications and Presentations

Bark beetle outbreaks result in massive amounts of deadwood which are a significant carbon reservoir that can impact forest ecosystems. Additionally, bark beetle-introduced symbiotic fungi in beetle-generated deadwood can increase termite presence and feeding. This could alter decomposition rates and saproxylic communities of bark beetle-generated deadwood. However, the fate of bark beetle-generated deadwood after tree mortality has received little attention despite the possibility bark beetles could alter decomposition processes and deadwood residence times at landscape scales following outbreaks. We tested the hypothesis that beetle-attacked trees decompose faster than unattacked trees. In Honduras, and Mississippi and Arizona, USA, we felled one …

Development Of Genomic Resources And Group Specific Markers For Evaluation Of Genetic Diversity Of Pathogenic Rhizoctonia Species, Juanita Gil Bedoya

Graduate Theses and Dissertations

Rhizoctonia is a complex genus in the phylum Basidiomycota comprised of several taxa distributed across different families in the order Cantharellales. Many species in the genus have been identified as plant pathogens, saprobes, or beneficial mycorrhizal symbionts of orchids. Rhizoctonia isolates are divided into binucleate and multinucleate and then classified into anastomosis groups (AGs) based on the ability of compatible hyphae to fuse. Binucleate Rhizoctonia species (Ceratobasidium spp.) are classified into 21 AGs identified with letters (AG-A to AG-U). Multinucleate Rhizoctonia species (Thanatephorus spp.) are identified with numbers and classified into 14 anastomosis groups (AG-1 to AG-13, and bridging group …

Cellular Control Of Proteostasis, Cytoskeleton Organization, And Polarity Remodeling During Infection-Related Development By The Rice Blast Fungus, Audra Rogers

Graduate Theses and Dissertations

Understanding the intricate processes underlying fungal infection-related development is crucial for combating plant pathogens. In this study, we investigate the coordination of morphogenetic transitions during plant infection by Magnaporthe oryzae, the blast fungus. We focus on three key aspects: protein quality control, cytoplasmic microtubule organization, and cell-end marker proteins. M. oryzae forms a specialized infection cell known as an appressorium. The proper formation of this cell is crucial for the pathogen to infect a susceptible host. First, we investigate protein quality control mechanisms during infection-related development. Our findings demonstrate that aggregated proteins are sequestered into quality control compartments within conidia …

Arkansas Soybean Research Studies 2022, Jeremy Ross

Arkansas Agricultural Experiment Station Research Series

Arkansas is the leading soybean-producing state in the mid-southern United States. Arkansas ranked 11th in soybean production in 2022 when compared to the other soybean-producing states in the U.S. The state represented 3.04% of the total U.S. soybean production and 3.64% of the total acres planted in soybean in 2022. The 2022 state soybean average yield was 52.0 bushels per acre, tying the previous state yield record of 52 bushels per acre set in 2021. The top five soybean-producing counties in 2022 were Mississippi, Crittenden, Phillips, Poinsett, and Arkansas (Table 1). These five counties accounted for over 35.7% of the …

The Pseudomonas Syringae Pv. Tomato Dc3000 Effector Hopd1 Interferes With Cellular Dynamics Associated With The Function Of The Plant Immune Protein Atnhr2b, Luis Francisco Marin-Ponce, Catalina Rodriguez-Puerto, Perla Rocha-Loyola, Clemencia M. Rojas

Entomology and Plant Pathology Faculty Publications and Presentations

The plant pathogenic bacterium Pseudomonas syringae pv. tomato DC3000 (Pst DC3000) causes disease in tomato, in the model plant Arabidopsis thaliana, and conditionally in Nicotiana benthamiana. The pathogenicity of Pst DC3000 is mostly due to bacterial virulence proteins, known as effectors, that are translocated into the plant cytoplasm through the type III secretion system (T3SS). Bacterial type III secreted effectors (T3SEs) target plants physiological processes and suppress defense responses to enable and support bacterial proliferation. The Pst DC3000 T3SE HopD1 interferes with plant defense responses by targeting the transcription factor NTL9. This work shows that HopD1 also targets the …

Arkansas Wheat Performance Tests 2022-2023, J. F. Carlin, R. B. Mulloy, R. D. Bond

Arkansas Agricultural Experiment Station Research Series

Wheat variety performance tests are conducted each year in Arkansas by the University of Arkansas System Division of Agriculture’s Arkansas Crop Variety Improvement Program.

The tests provide information to companies developing cultivars and marketing seed within the state and aid the Arkansas Cooperative Extension Service in formulating variety recommendations for small-grain producers. The tests were conducted at the Northeast Research and Extension Center at Keiser, the Vegetable Substation near Kibler, the Lon Mann Cotton Research Station near Marianna, the Pine Tree Research Station near Colt, and the Rohwer Research Station near Rohwer. Specific location and cultural practice information accompany each …

Development And Use Of A Detached Leaf Assay To Assess Soybean Cultivar Resistance To Target Spot, Caused By Corynespora Cassiicola, Rachael Wolf

Graduate Theses and Dissertations

Target spot, caused by the fungus Corynespora cassiicola, was once considered a minor foliar disease of soybean in the US. However, a severe outbreak of target spot occurred in the southeastern U.S in 2016. Due to the lack of information on resistance in soybean cultivars, and the challenges in screening cultivars in the field, a detached leaf assay was developed to evaluate resistance. The objectives of the effort were to 1) develop a greenhouse inoculation method of soybean with C. cassiicola 2) use that method to compare reactions of soybean germplasm lines to target spot 3) collect and characterize isolates …

B. R. Wells Arkansas Rice Research Studies 2022, 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 50.1% of total U.S. rice production and 49.8% of the total acres planted to rice in 2022. 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 …

Arkansas Corn And Grain Sorghum Research Studies 2022, Victor Ford, Jason Kelley, Nathan Mckinney Ii

Arkansas Agricultural Experiment Station Research Series

The 2022 edition of the Arkansas Corn and Grain Sorghum Research Studies Series includes research results on topics pertaining to corn and grain sorghum production, including weed, disease, and insect management; economics; sustainability; irrigation; post-harvest drying; soil fertility; mycotoxins; cover crop management; and research verification program results. Our objective is to capture and broadly distribute the results of research projects funded by the Arkansas Corn and Grain Sorghum Board. The intended audience includes producers and their advisors, current investigators, and future researchers. The Series serves as a citable archive of research results.

Reports in this publication are 2–3 year summaries. …

Genomic Analyses Of A Widespread Blueberry Virus In The United States, Daisy Stainton, Dan E.V. Villamor, Andrea Sierra Mejia, Ashish Srivastava, Dimitre Mollov, Robert R. Martin, Ioannis E. Tzanetakis

Entomology and Plant Pathology Faculty Publications and Presentations

Screening of blueberry accessions using high throughput sequencing revealed the presence of a new virus. Genomic structure and sequence are similar to that of nectarine stem pitting associated virus (NSPaV), a member of the genus Luteovirus, family Tombusviridae. The full genome of the new luteovirus, tentatively named blueberry virus L (BlVL), was characterized and analyzed. Similar to NSPaV, BlVL does not contain readily identifiable movement proteins in any of the seven isolates sequenced. More than 600 samples collected from five states were screened and 79% were found infected, making BlVL the most widespread blueberry virus in the United States.

International Rice Outlook: International Rice Baseline Projections 2022-2032, A. Durand-Morat, S. Bairagi, W. Mulimbi

AAES Research Reports and Research Bulletins

Rice prices in Asia increased since the Summer of 2022 mainly due to worries about a reduction in rice production in India caused by an abnormal monsoon season (Fig. 1). The upward trend in export prices solidified after India implemented a 20% export tariff on brown and milled long-grain rice, and a complete ban on exports of broken rice, in September 2022 to curve down exports and release the pressure on domestic rice prices. India’s rice export prices increased since then and proportionally to the value of the export tax. The latest estimates put rice production at 128 million metric …

Arkansas Soybean Performance Tests 2022, J. F. Carlin, R. B. Mulloy, R. D. Bond

Arkansas Agricultural Experiment Station Research Series

Soybean variety and strain performance tests are conducted each year in Arkansas by the University of Arkansas System Division of Agriculture’s Arkansas Crop Variety Improvement Program. The tests provide information to companies developing varieties and/ or marketing seed within the state, and aid the Arkansas Cooperative Extension Service in formulating variety recommendations for soybean producers.

A Genome-Wide Association Study And Genomic Prediction For Phakopsora Pachyrhizi Resistance In Soybean, Haizheng Xiong, Yilin Chen, Yong-Bao Pan, Jinshe Wang, Weiguo Lu, Ainong Shi

Horticulture Faculty Publications and Presentations

Soybean brown rust (SBR), caused by Phakopsora pachyrhizi, is a devastating fungal disease that threatens global soybean production. This study conducted a genome-wide association study (GWAS) with seven models on a panel of 3,082 soybean accessions to identify the markers associated with SBR resistance by 30,314 high quality single nucleotide polymorphism (SNPs). Then five genomic selection (GS) models, including Ridge regression best linear unbiased predictor (rrBLUP), Genomic best linear unbiased predictor (gBLUP), Bayesian least absolute shrinkage and selection operator (Bayesian LASSO), Random Forest (RF), and Support vector machines (SVM), were used to predict breeding values of SBR resistance using …

Investigating The Role Of The Sumo-Activating Enzyme, Uba2, In Infection-Related Morphogenesis Of Magnaporthe Oryzae, Rachel Taylor

Biological Sciences Undergraduate Honors Theses

The plant pathogenic fungus Magnaporthe oryzae forms a specialized pressure-generating infection cell called an appressorium on the leaf surface, which it uses to mechanically rupture the otherwise impenetrable cuticle, enabling colonization of the underlying tissue and the establishment of blast disease. Appressorium differentiation by M. oryzae is cell cycle-regulated and requires programmed cell death of a three-celled propagative spore, as well as extensive remodeling of the microtubule, actin, and septin cytoskeletons. Recent studies have proposed the importance of sumoylation – the enzymatic conjugation of a small ubiquitin-like modifier to target proteins, for various aspects of infection-related development by M. oryzae, …

Evaluation Of Biological And Chemical Seed Treatments For Management Of Rice Diseases, Sherif Adam Sharfadine

Graduate Theses and Dissertations

Rice is the primary staple for more than half of the global population and is the second most important cereal worldwide. In the US, rice is primarily grown in the southern states, with Arkansas leading production and responsible for 47% of the total rice production in the country. Diseases cause significant yield losses in rice. Sheath blight, rice blast and bacterial panicle blight are the main diseases in rice and cause significant yield losses. Sheath blight alone could cause up 50% yield loss in heavily damaged fields with highly susceptible cultivars. Additionally, rice seed and seedling diseases primarily caused by …

Micronutrient Concentration Effects On Lettuce Growth And Susceptibility To Pythium, Kalyn M. Helms

Graduate Theses and Dissertations

In hydroponic production waterborne pathogens such as Pythium are ubiquitous and continually threaten a wide range of Controlled Environment Agriculture (CEA) crops in hydroponic production, including but not limited to: lettuce, spinach, basil, arugula, cucumber, tomato, sweet pepper, roses, chrysanthemums, and cannabis (Sutton et al., 2006; Gull, 2002; McGehee and Raudales, 2021; Gillespie, 2020). Despite extensive sanitation measures, disease control in hydroponics is fallible and requires constant surveillance and management to minimize outbreaks (Sutton et al., 2006). A potential disease suppression strategy is to increase micronutrient concentrations within hydroponic systems to naturally strengthen plant defenses against pathogens such as Pythium. …

Arkansas Soybean Research Studies 2021, Jeremy Ross

Arkansas Agricultural Experiment Station Research Series

Arkansas is the leading soybean-producing state in the mid-southern United States. Arkansas ranked 11th in soybean production in 2021 compared to the other soybean-producing states in the U.S. The state represented 3.49% of the total U.S. soybean production and 3.49% of the total acres planted in soybean in 2021. The 2021 state soybean average yield was 52.0 bushels per acre, setting a new state record and surpassing the previous yield record of 51.5 bushels per acre set in 2020. The top five soybean-producing counties in 2021 were Mississippi, Phillips, Crittenden, Poinsett, and Arkansas (Table 1). These five counties accounted for …