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2024 Update Mtg Jan 30: Phytophthora Root Rot Study Updates, Sai Sree Uppala, Salisu Sulley

Cranberry Station Extension meetings

No abstract provided.

An Experimental Comparison Of Stand Management Approaches To Sudden Oak Death: Prevention Vs. Restoration, Gissella B. Quiroga, Allison B. Simler-Williamson, Kerri M. Frangioso, Susan J. Frankel, David M. Rizzo, Richard C. Cobb

Biology Faculty Publications and Presentations

Many coastal forests stretching from central California to southwest Oregon are threatened or have been impacted by the invasive forest pathogen Phytophthora ramorum, the cause of sudden oak death. We analyzed a set of stand-level forest treatments aimed at preventing or mitigating disease impacts on stand composition, biomass, and fuels using a before–after-control-intervention experiment with a re-evaluation after 5 years. We compared the effects of restorative management for invaded stands and preventative treatments for uninvaded forests with two stand-level experiments. The restorative treatments contrasted two approaches to mastication, hand-crew thinning, and thinning with pile burning with untreated controls replicated …

Sudden Oak Death And Ramorum Blight, Marion Murray, Ann Mull

All Current Publications

Sudden oak death (SOD) and ramorum blight are caused by Phytophthora ramorum, a non-native water mold (oomycete) that originates from parts of Asia. Sudden oak death was given its name due to the appearance that entire trees were dying in just 2 to 4 weeks. In reality, the disease progresses over an extended period, estimated at more than 2 years after initial infection. Ramorum blight is nonlethal, typically causing foliar browning and wilting. This fact sheet discusses impact, damage and symptoms, plant hosts, disease cycle, and management.

Molecular Identification Of Oomycete Species Associated With Woody Plants In Louisiana And Survey Of Oomycete Species Associated With Live Oak Trees Planted On The Louisiana State University Campus, Hamilton Crockett

LSU Master's Theses

Three Oomycetes genera, Phytophthora, Phytopythium and Pythium, contain many important plant pathogens. Historically, Phytophthora infestans, responsible for the great Irish potato famine, and Phytophthora ramorum, causal agent of sudden oak death disease, are the two better-known high impact pathogens. The LSU AgCenter Plant Diagnostic Center (PDC) has been isolating putative Phytophthora and related species from combined root and soil samples collected from various woody ornamentals and trees for over a decade. In August of 2016, Louisiana received torrential rains, which resulted in historic flooding in several southern parishes. During subsequent years, the PDC staff isolated a …

Comparative Genomic Analysis Of 31 Phytophthora Genomes Reveals Genome Plasticity And Horizontal Gene Transfer, Brent A. Kronmiller, Nicolas Feau, Danyu Shen, Javier F. Tabima, Shahin S. Ali, Andrew D. Armitage, Felipe Arredondo, Bryan A. Bailey, Stephanie R. Bollmann, Angela Dale, Richard J. Harrison, Kelly Hrywkiw, Takao Kasuga, Rebecca Mcdougal, Charlotte F. Nellist, Preeti Panda, Sucheta Tripathy, Nari M. Williams, Wenwu Ye, Yuanchao Wang, Richard C. Hamelin, Niklaus Grünwald

Biology

Phytophthora species are oomycete plant pathogens that cause great economic and ecological impacts. The Phytophthora genus includes over 180 known species, infecting a wide range of plant hosts, including crops, trees, and ornamentals. We sequenced the genomes of 31 individual Phytophthora species and 24 individual transcriptomes to study genetic relationships across the genus. De novo genome assemblies revealed variation in genome sizes, numbers of predicted genes, and in repetitive element content across the Phytophthora genus. A genus-wide comparison evaluated orthologous groups of genes. Predicted effector gene counts varied across Phytophthora species by effector family, genome size, and plant host range. …

Distribution And Frequency Of Aquatic Oomycetes Throughout Marin County In Relation To Physical Chemical Water Parameters, Franki Crites

Natural Sciences and Mathematics | Biological Sciences Master's Theses

Oomycetes, also known as water molds, belong to the kingdom Stramenopila and are a well-known group of plant pathogens and saprophytes. Important species include Phytophthora ramorum (causal agent of sudden oak death), Pythium aphanidermatum (root rot), and Phytophthora infestans (late potato blight), all major threats to the environment, agriculture, and the economy. Although many oomycete species have been found in various water sources, little is known about the correlation between the distribution and frequency of oomycetes in aquatic environments and physical chemical water parameters. The objective of this study was to detect and identify aquatic oomycetes from Marin County using …

Evaluation Of Bell Pepper Cultivars With And Without Resistance To Bacterial Leaf Spot And Phytophthora, West Central Minnesota, Nathan Dalman, Steve Poppe

Midwest Vegetable Trial Reports

Bacterial leaf spot (BLS) and Phytophthora (PHY) diseases are a common problem for Minnesota bell pepper producers and if not detected and treated early enough, these diseases can kill the plants. There are cultivars that have resistance to these particular diseases but these cultivars must maintain yields similar to traditional cultivars in order to be desired by producers and buyers. Our goal was to determine any differences in performance between cultivars with and without resistance. Yield, fruit size and number of fruit per plant were the evaluated characteristics.

Screening Potential Citrus Rootstocks For Phytophthora Nicotianae Tolerance, Madhurababu Kunta, Sandy Chavez, Zenaida Viloria, Hilda S. Del Rio, Madhavi Devanaboina, George Yanev, Jong-Won Park, Eliezer S. Louzada

School of Mathematical and Statistical Sciences Faculty Publications and Presentations

Seeds from four citrus rootstocks including sour orange, Bitters-C22 citrandarin, Sarawak pummelo 3 Rio Red grapefruit, and Sarawak pummelo 3Bower mandarin were exposed to high inoculum levels of Phytophthora nicotianae to screen for tolerance. Inoculation of pregerminated seeds (PGIS) and non-PGIS was carried out. The average P. nicotianae propagule counts from the soil samples where these seedlings were raised ranged from 424 to 1361 colony forming units/cm3. The proportion of live to dead plants was recorded at 11months postinoculation, which showed that Sarawak3Bower performed significantly better than other rootstocks. Evaluation of the rootstocks 18 months postinoculation resulted in only one …

Evaluation Of The Potential For Ecological Treatment Technologies To Remediate Species Of Phytophthora From Irrigation Runoff, Natasha Lynn Bell

All Dissertations

Increased incidences and severity of drought have reduced reliable access to freshwater sources for irrigation purposes by nursery and greenhouse plant producers. Many plant producers are now considering onsite remediation and reuse of water captured from irrigation runoff. However, potential contamination of recycled water with plant pathogens, primarily species of Phytophthora, is the primary concern preventing many growers from reusing their water. Species of Phytophthora are capable of infecting thousands of host plants and cause some of the most economically important diseases of nursery and greenhouse crops worldwide. Phytophthora spp. produce motile, swimming zoospores that often serve as propagules …

Evaluation Of Fungicides And Biofungicide To Control Phytophthora Root Rot (Phytophthora Cinnamomi Rands) And Ambrosia Beetles (Coleoptera: Curculionidae: Scolytinae) On Flowering Dogwoods Exposed To Simulated Flood Events, Matthew S. Brown, Fulya Baysal-Gurel, Jason B. Oliver, Karla M. Addesso

Agricultural and Environmental Sciences Faculty Research

Phytophthora root rot causes major economic losses in woody ornamental nurseries, especially in plants exposed to flooding. Ambrosia beetles, which attack stressed trees, are also important pests of woody plants. In this study, several products were evaluated for control of Phytophthora root rot and ambrosia beetles on containerized flowering dogwoods (Cornus florida L.) exposed to simulated flood events under field conditions. In two trials, preventive (7 days preflooding) or curative (1 day postflooding) sprench (combination spray and drench) treatments were applied to containerized dogwoods artificially inoculated with Phytophthora cinnamomi Rands. The plants were flooded by maintaining standing water for 1, …

Interaction Of A Preventative Fungicide Treatment And Root Rot Pathogen On Ambrosia Beetle Attacks During A Simulated Flood Event, Karla Addesso, Fulya Baysal-Gurel, Jason Oliver, Christopher Ranger, Paul O'Neal

Agricultural and Environmental Sciences Faculty Research

Flooding can increase tree susceptibility to root rot pathogens as well as attacks by ambrosia beetles attracted to stress-induced ethanol emissions. The objective of this study was to investigate the interaction of a preventative fungicide treatment and root infection with Phytophthora cinnamomi on ambrosia beetle attacks in flood stressed trees. A fungicide (Pageant® Intrinsic®) was evaluated in two flood trials using Eastern redbud and tulip poplar trees with treatments including the fungicide with or without pathogen or no fungicide with or without pathogen. Fungicide treated trees had fewer ambrosia beetle attacks, particularly in trees without P. cinnamomi co-infection. In a …

Phytophthora Cinnamomi Colonized Reclaimed Surface Mined Sites In Eastern Kentucky: Implications For The Restoration Of Susceptible Species, Kenton L. Sena, Kevin M. Yeager, Tyler J. Dreaden, Christopher D. Barton

Forestry and Natural Resources Faculty Publications

Appalachian forests are threatened by a number of factors, especially introduced pests and pathogens. Among these is Phytophthora cinnamomi, a soil-borne oomycete pathogen known to cause root rot in American chestnut, shortleaf pine, and other native tree species. This study was initiated to characterize the incidence of P. cinnamomi on surface mined lands in eastern Kentucky, USA, representing a range of time since reclamation (10, 12, 15, and 20 years since reclamation). Incidence of P. cinnamomi was correlated to soil properties including overall soil development, as indicated by a variety of measured soil physical and chemical parameters, especially the …

Pseudomonas And Burkholderia Inhibit Growth And Asexual Development Of Phytophthora Capsici, Amena Khatun, Tarin Farhana, Abdullah As Sabir, Shah Mohammad Naimul Islam, Helen M. West, Mahfuzur Rahman, Tofazzal Islam

Faculty & Staff Scholarship

The objective of this study was to isolate and characterize antagonistic rhizobacteria from chili against a notorious phytopathogen Phytophthora capsici. Among the 48 bacteria isolated, BTLbbc-02, BTLbbc-03, and BTLbbc-05 were selected based on their inhibitory activity against P. capsici. They were tentatively identified as Burkholderia metallica BTLbbc-02, Burkholderia cepacia BTLbbc-03, and Pseudomonas aeruginosa BTLbbc-05, respectively, based on their 16S rRNA gene sequencing. All inhibited the growth of P. capsici at varying levels by inducing characteristic morphological alterations of P. capsici hyphae. The cell-free culture supernatant of all three isolates impaired motility (up to 100%) and caused lysis …

First Interspecific Genetic Linkage Map For Castanea Sativa X Castanea Crenata Revealed Qtls For Resistance To Phytophthora Cinnamomi, Carmen Santos, Charles Dana Nelson, Tetyana Zhebentyayeva, Helena Machado, José Gomes-Laranjo, Rita Lourenço Costa

Forest Health Research and Education Center Faculty Publications

The Japanese chestnut (Castanea crenata) carries resistance to Phytophthora cinnamomi, the destructive and widespread oomycete causing ink disease. The European chestnut (Castanea sativa), carrying little to no disease resistance, is currently threatened by the presence of the oomycete pathogen in forests, orchards and nurseries. Determining the genetic basis of P. cinnamomi resistance, for further selection of molecular markers and candidate genes, is a prominent issue for implementation of marker assisted selection in the breeding programs for resistance. In this study, the first interspecific genetic linkage map of C. sativa x C. crenata …

Genetic Analysis Of Field Populations Of The Plant Pathogens Cercospora Sojina, Corynespora Cassiicola And Phytophthora Colocasiae, Sandesh Kumar Shrestha

Doctoral Dissertations

Genetic markers and whole genome sequencing (WGS) were used to study the disease dynamics and population structure for three important plant pathogens; Cercospora sojina (frogeye leaf spot of soybean), Corynespora cassiicola (target spot of soybean, cotton and many other crops) and Phytophthora colocasiae (taro leaf blight). For each pathogen, genome sequencing was used to guide the development of single nucleotide polymorphism (SNP) markers and both were used to investigate diversity in field populations. Investigation of C. sojina in Tennessee included comparisons of extant populations and historical isolates, revealing a dominant, potentially long-lived, clonal lineage. Characterization of QoI fungicide resistance indicates …

Phytophthora Species Associated With American, Chinese, And Backcross Hybrid Chestnut Seedlings In Field Sites In The Southeastern United States, Suzette Ruth Sharpe

All Theses

Phytophthora root rot was first described on American chestnut (Castanea dentata) in a preliminary report in 1932 and the causal agent was tentatively and erroneously identified as P. cambivora. Soon after, the causal agent was correctly identified as P. cinnamomi and, since that time, P. cinnamomi has been the only species reported to cause Phytophthora root rot on the American chestnut. In the early 1980s, The American Chestnut Foundation initiated a backcross breeding program to develop chestnut trees that had resistance to Cryphonectria parasitica which causes chestnut blight. In the early 2000s, backcross hybrid chestnut seedlings ([American …

Phytophthora Sojae Infecting Soybean: Pathotype Diversity, New Sources Of Resistance And Interaction With The Soybean Cyst Nematode, Rawnaq Nazneen Chowdhury

Electronic Theses and Dissertations

Phytophthora root and stem rot, caused by Phytophthora sojae Kaufmann and Gerdemann, is an important disease of soybean (Glycine max L.) in South Dakota. To gain a better understanding of the importance of P. sojae in South Dakota, specifically pathotype diversity, identification of new resistance sources and the interaction with the soybean cyst nematode (Heterodera glycines Ichinohe, SCN), this research was undertaken with the following objectives - 1) to characterize the pathotype diversity of P. sojae causing Phytophthora root and stem rot on soybean in commercial fields in South Dakota; 2) to compare inoculation methods to evaluate for …

In Silico Study Of Rxlr Effectors Of Phytophthora Infestans Hp-10-31, A2 Mating Type Potato Late Blight Pathogen, Youvika Singh, Virupaksh U. Patil, Anupam Dhasmana, Swarup K. Chakraborty, Pradeep K. Shukla, Shashi Rawat

School of Medicine Publications and Presentations

Phytophthora infestans is one of the most compelling plant pathogen among the scientific community throughout the world. It is the causative agent of potato late blight and responsible for tremendous economic loss worldwide. Pathogenic effector proteins are instrumental in modulating host immunity and disease resistance has been a major concern. In P. infestans, a class of cytoplasmic effectors recognized as RxLR is characterized by highly conserved region and abet in parasitic colonization by modifying the host defense system. We have sequenced an Indian strain of P. infestans HP-10-31 genome and identified several RxLR motif-containing genes.In this study we selected two …

Characterization Of A Novel Clade Of Transporters In Phytophthora, Stephanie Padula, Paul F. Morris Dr, Howard Casey Cromwell Dr., Menaka Ariyaratne, Andrew Wagner

Honors Projects

The oomycete Phytophthora parasitica has a worldwide distribution and is an economically important pathogen of more than 100 species⁴. RNA-seq analysis showed that one gene, PPTG_16698 has the 5^th highest level of expression of all transport proteins in the zoospore stage, and is highly conserved throughout Phytophthora species. This project attempts to characterize the important biological role that PPTG_16698 plays in P. parasitica and other oomycetes. Three strategies have been implemented to accomplish this goal: growth analysis by heterologous expression in yeast, metabolite analysis in yeast, and construction of a GFP fusion protein to enable localization of …

Bot Canker Pathogens Could Complicate The Management Of Phytophthora Black Pod Of Cocoa, Idowu Jaiyeola, Rufus J. Akinrinlola, Gbodope S. Ige, Oluwatimilehin O. Omoleye, Abiola Oyedele, Bayode J. Odunayo, Omotayo J. Emehin, Marcus O. Bello, Anthony O. Adesemoye

Department of Plant Pathology: Faculty Publications

Black pod is a major hindrance to cocoa production in Nigeria. It is caused by three different Phytophthora species with Phytophthora megakarya as the most important species in Nigeria and West African subregion. Phytophthora spp. may enhance infections by opportunistic pathogens such as members of the Botryosphaeriacea that cause branch and trunk cankers in many woody plants across the world. Botryosphaeriacea has not been reported in cocoa nor in any woody plants in Nigeria to our knowledge. In the cocoa belt of Nigeria, research and understanding on cocoa black pod and Phytophthora is limited partly because of delayed or no …

Phytophthora Foliage Blight Of Garden Phlox: Phytophthora Nicotianae On Phlox Paniculata, Daniel Drechsler

All Theses

Phytophthora foliage blight of garden phlox (Phlox paniculata ) - caused by Phytophthora nicotianae - is a devastating disease that has been seen consistently in nursery production facilities in South Carolina. However, this disease has not been characterized previously. This project was composed of three separate studies, each of which followed one of the three major components of the disease triangle (i.e., the synchronous occurrence of a susceptible host and a virulent pathogen within a conducive environment) to investigate the pathogenicity of P. nicotianae on P. paniculata . In one study, the efficacies of three inoculation methodologies to cause …

Diversity Among Isolates Of Phytophthora Cinnamomi From Ornamental Plants In South Carolina, Simon Schreier

All Theses

Phytophthora cinnamomi is a devastating pathogen that can attack over 900 hosts. It is the most common species of Phytophthora isolated from woody ornamental crops in South Carolina but little is known about variability among isolates of P. cinnamomi that attack these plants. Therefore, 142 isolates of P. cinnamomi recovered from diseased plant samples submitted to the Clemson University Plant Problem Clinic between 1995 and 2011 were characterized for mycelium growth habit, growth rate, mefenoxam sensitivity, mating type, and sporangium morphology. Mycelium growth habit on PARPH-V8 selective medium was classified as aerial, appressed, or dwarf; 87% of isolates had the …

Evaluation Of Wetland Plants For Susceptibility To Species Of Phytophthora Present In Runoff Water At Ornamental Plant Nurseries, Garrett Ridge

All Theses

Competition between agricultural producers and urban communities for high quality water is increasing; therefore, growers need to adopt water conservation and reuse practices to ensure an adequate supply of irrigation water. One concern with recycled irrigation water is the potential to recirculate propagules of oomycete pathogens. Constructed wetlands are a biologically-based treatment option for nutrient and chemical remediation that potentially also could filter pathogen propagules. The goal of this study was to assess the susceptibility of plants routinely used in constructed wetlands to infection by species of Phytophthora commonly found at ornamental plant nurseries. In laboratory and greenhouse experiments, an …

Understanding Gafp, A Plant Lectin With Broad Spectrum Inhibitory Activity, Alexis Nagel

All Dissertations

South Carolina and Georgia are the largest peach producing regions in the Southeastern United States, generating about $60 million worth (~90,000 tons) of fruit per year on average. Peaches and other stone-fruits (Prunus sp.) can be afflicted by a variety of root-associated diseases which negatively impact annual yield and long-term tree mortality. An engineered Prunus rootstock with enhanced resistance to soil-borne pathogens would therefore be of great benefit to the Southeastern peach industry. The Gastrodia anti-fungal protein (GAFP) is a monocot mannose-binding lectin which is able to inhibit the growth of multiple species of plant pathogenic fungi. Previous findings from …

Investigating Genetic Diversity Of Phytophthora Spp. And Related Oomycetes, Jonathan Patrick Hulvey

Doctoral Dissertations

Oomycetes, like fungi, are filamentous heterotrophs, but unlike true fungi are diploid and share a photosynthetic ancestor. Many of these organisms are plant and animal pathogens, and members of the genus Phytophthora cause devastating disease on a diverse array of agricultural plant hosts. Several diverse topics in oomycete biology are investigated in this dissertation. Chapter 2 is a report on loss of heterozygosity in Phytophthora capsici in response to chemical mutagenesis.The research presented in Chapters 3 and 4 are centered on documenting biodiversity and genetic diversity of populations of Phytophthora species obtained from infected plant hosts. The final chapter (Chapter …

Diseases Of Floriculture Crops In South Carolina: Evaluation Of A Pre-Plant Sanitation Treatment And Identification Of Species Of Phytophthora, Ernesto Robayo Camacho

All Theses

This project was composed of two separate studies. In one study, the species of Phytophthora that have been found associated with diseased floriculture crops in South Carolina and four other states were characterized and identified using molecular (RFLP fingerprints and DNA sequences for ITS regions and cox I and II genes), morphological (sporangia, oogonia, antheridia, oospores, and chlamydospores), and physiological (mating behavior and cardinal temperatures) characters. In addition, sensitivity to the fungicide mefenoxam was determined. In all, 87 isolates from 63 host plants that were collected over a 13-year period (1996 through 2008) were examined. Host plants came from 46 …

Survey Of Blueberry (Vaccinium Spp.) Problems In The Gulf South, Melinda A. Miller-Butler, Kenneth J. Curry, Barbara J. Smith, Jeffrey S. Braswell

Faculty Publications

The blueberry (Vaccinium) industry in Mississippi has been steadily increasing since the early 1980s, but some plants in older fields are now in decline. The root rot pathogen, Phytophthora cinnamomi, is endemic in the southeastern United States and has caused severe losses to blueberries in North Carolina and Arkansas. Because the warm, humid climate of Mississippi, with periods of high precipitation, provides a favorable environment for Phytophthora root rot disease, it was suspected to be the cause of plant decline in older blueberry fields. Members of the Gulf South Blueberry Growers Association were mailed surveys to determine …

Phytophthora Diseases Of Cutflower Crops, Department Of Agriculture And Food, Western Australia

Bulletins 4000 -

Phytophthora root rot is the most common soil borne disease causing plant death in native cut flower production. It is also a pathogen of exotic cutflower crops such as rose, lily, carnation, proteas and gerbera. The fungus, Phytophthora cinnamomi, the cause of jarrah dieback is the pathogen that first comes to mind when Phytophthora is mentioned. This has one of the widest host ranges of all Phytophthora species, particularly amongst native Australia species. P.nicotianae also has a wide host range, infecting a wide range of exotic, as well as Australian native flower crops. There are also a number of …

Sampling And Testing For Plant Pathogens, Aileen Reid

Bulletins 4000 -

There are many methods used in the laboratory to determine whether Phytophthora or other fungi are present in growing media, water supply and diseased plants. These include:

• filtering water for spores

• baiting for fungi in growing media and water samples

• examining diseased plant tissue microscopically

• direct culturing from roots and other plant parts to isolate the fungal pathogen in pure culture.

This bulletin outlines some of the procedures involved. Growers may be able to do some basic baiting of soil or water samples themselves to alert them of a problem but the procedures involved in isolating …

First Report Of Phytophthora Insolita And P. Inflata On Rhododendron In Ohio, Antonino Testa, Mikael Schilb, Jeffery S. Lehman, Gennaro Cristinzio, Pierluigi Bonello

Biology and Earth Science Faculty Scholarship

During August 2003, we conducted a statewide survey of rhododendrons to determine if Phytophthora ramorum was present in Ohio ornamental nurseries. In total, 240 samples were randomly collected in 12 nurseries throughout Ohio from rhododendrons showing foliar necrotic lesions and twig dieback symptoms.