Plant Pathology Commons^™

Investigation Of Basil Downy Mildew Pathogen Survival, New Pathotype Development And Sources Of Quantitative, Kelly S. Allen

Doctoral Dissertations

Basil downy mildew (BDM) caused by the oomycete pathogen Peronospora belbahrii, threatens sweet basil (Ocimum basilicum) production worldwide. Chemical and cultural control options for BDM are limited, and resistant cultivars have only recently become available for commercial production. To address this challenging agricultural disease, this research investigates BDM epidemiology, occurrences of new pathotypes, and molecular plant-pathogen interactions leading to host resistance or susceptibility. A reproducible low-resource inoculation protocol was developed to harvest P. belbahrii inoculum and propagate BDM for further research. The survival of P. belbahrii sporangia was examined using an in vitro assay to assess germination …

Screening For Binding Partners And Protein-Protein Interactions Of A Fungal Transcription Factor- Xdr1, Nishadi Punsara Gallala Gamage

Masters Theses

Clarireedia spp. (formerly Sclerotinia homoeocarpaF.T. Bennett) is the causal agent dollar spot, the most economically important turfgrass disease impacting golf courses in North America. The most effective strategy for dollar spot control is repeated application of multiple classes of fungicides. However, reliance on chemical application has led to resistance to four classes of fungicides as well as multidrug resistance (MDR). Fungi are known to detoxify xenobiotics, like fungicides, through transcriptional regulation of three detoxification phases: modification, conjugation and secretion. Little is known, however, of the protein-protein interactions that facilitate these pathways. Following next-generation RNA sequencing of Clarireedia spp., a …

The Role Of Low-Molecular Weight Fungal Metabolites In Eutypa Dieback Grapevine Trunk Disease, Dana Sebestyen

Masters Theses

Eutypa dieback, one of several grapevine trunk diseases (GTDs), is of serious concern to the grape industry globally. This disease is caused by the fungus Eutypa lata but it is often seen in consortia growth with Phaeoacremonium minimum and Phaeomoniella chlamydospora. It is vital to understand the mechanisms for how this disease functions to develop control measures to combat it. Brown rot fungi are able to use a complex of low molecular weight (LMW) metabolites to induce a Fenton reaction to deconstruct woody tissue. These metabolites are part of a chelator mediated Fenton (CMF) chemistry that produces reactive oxygen …

Characterizing The Interaction Between Non-Pathogenic Fusarium Oxysporum And Arabidopsis Thaliana To Determine Beneficial Effects Conferred To The Model Plant Host, Kathryn Isabelle Vescio

Masters Theses

Fusarium oxysporum (Fo) is a soil-borne fungal pathogen that causes vascular wilt disease on a broad range of plants, including agricultural crops and the model plant Arabidopsis thaliana. There are non-pathogenic members of the Fo species complex that confer defense benefits against other pathogens to the host plant, however alteration to the host’s physiology through interaction with one of these strains, Fo47, have not been described. In this study, we aimed to establish the Fo47-A. thaliana interaction and determine if Fo47 reduces disease severity of a pathogenic Fo isolate, Fo5176. Additionally, we sought to use bioinformatics to mine …

The Good, The Bad, And The Ugly: Pollinators As Vectors Of Mummy Berry Disease In Highbush Blueberry, Matthew Boyer

Doctoral Dissertations

Background: Many plants must balance the need for pollination services with mediating the risk of pollinator-vectored pathogens. Vaccinium corymbosum, highbush blueberry, is negatively affected by an insect-vectored, fungal plant pathogen, Monilinia vaccinii-corymosi (MVC), the cause of mummy berry disease, in which the asexual spore mimics pollen grains and is transferred from blighted tissue to flowers via pollinators, resulting in inedible, hardened fruits. Highbush blueberry plants require outcrossed pollen for maximum yield and fecundity. Therefore, yield of blueberry plants rely on a balance between adequate pollination service and disease avoidance. Approach: To explore the relationship between pollinator community and infection …

Apple Disease Forecasting Models: When Climate Changes The Rules, Elizabeth W. Garofalo

Masters Theses

With a changing global climate, plant pathologists must understand the impact aberrant weather events may have on the development of plant diseases. Fungal plant infections are largely dependent on temperature and precipitation, climate parameters that are predicted to change more in this century. Venturia inaequalis causes apple scab, one of the most destructive apple diseases of temperate growing regions. Temperature and precipitation drive apple scab infections and forecast models, which guide growers in efficient, effective fungicide applications. In some recent years in the Northeast, these models have failed to accurately predict when ascospores of this fungus are available to cause …

A Plant Pathology View Of Signaling: A Computational Study Of Fusarium Oxysporum Kinomes And Downy Mildew Resistance In Sweet Basil, Gregory Deiulio

Doctoral Dissertations

This dissertation is composed of two projects that focus on pathogen and plant signaling within the framework of plant pathology. The first project targets protein kinases within the species complex Fusarium oxysporum based on genomic information and tracks their presence/absence and copy number variation across evolutionary time. We have predicted the kinomes of 19 Ascomycete fungi using the kinase annotating software Kinannote. Among Fusaria, kinases related to the perception of the environment, such as Histidine kinases, are proliferated. Similarly, I observed the expansion of Target of Rapamycin (TOR) kinase that regulates cell growth and development in responding to environmental cues. …

Tracking 19th Century Late Blight From Archival Documents Using Text Analytics And Geoparsing, Laura Tateosian, Rachael Guenter, Yi-Peng Yang, Jean Ristaino

Free and Open Source Software for Geospatial (FOSS4G) Conference Proceedings

In 1845, Ireland's potato crop was struck by a devastating potato disease that killed Ireland’s crop caused devastation for seven years and led to mass starvation and emigration from the country. The cause of the potato destruction was a fungus-like plant pathogen. There are several theories about the origin of the disease and the source of the 19th century outbreaks. We use historical documents contemporary to that time to investigate spatial information that might inform these mysteries. We present methodologies for automatically extracting information from these voluminous data sources. We identify and map geographic locations that are proximate in the …

Investigation Of Cytochrome P450 Monooxygenases In S. Homoeocarpa For Chlorothalonil Biotransformation, Robert Green

Masters Theses

Sclerotinia homoeocarpa (F.T. Bennett) is one of the most economically important pathogens on high amenity cool-season turfgrasses where it causes dollar spot. Due to decades of over-reliance and repeated chemical treatments, S. homoeocarpa has developed resistance and insensitivity to multiple classes of fungicides. To understand the genetic mechanisms of fungicide resistance, the whole genomes of two strains with varying resistance levels to fungicides, were sequenced. In unpublished data (Sang et al.), a RNA-sequencing analysis revealed three CYP450s that were validated to play a functional role in S. homoeocarpa’s resistance against different fungicide classes. We also identified CYP450 metabolic action …

Investigation Of Fungicide Resistance Mechanisms And Dynamics Of The Multiple Fungicide Resistant Population In Sclerotinia Homoeocarpa, Hyunkyu Sang

Doctoral Dissertations

A filamentous ascomycete fungus Sclerotinia homoeocarpa causes dollar spot, which is the most important disease of turfgrasses in the United States. Despite the increased number of reports of site-specific fungicide resistance and a recent report of multidrug resistance (MDR) in S. homoeocarpa field populations, the genetic mechanisms behind resistance or reduced sensitivity to fungicides remain poorly explained in the fungus. In order to prevent further development of fungicide resistance in the dollar spot pathosystem, a detailed elucidation of mechanisms of site-specific fungicide resistance and MDR is needed. In addition, the previous studies of MDR in fungi mostly focused on efflux …

Identification And Epidemiological Features Of Important Fungal Species Causing Sooty Blotch On Apples In The Northeastern United States, Angela Marie Madeiras

Doctoral Dissertations

The sooty blotch and flyspeck (SBFS) complex causes blemishes on apples in humid, temperate growing regions worldwide. In contrast to flyspeck etiology, the many species of fungi causing sooty blotch (SB) have not been well studied. The first set of objectives in this study was to use PCR to identify SB species isolated from apples and selected reservoir hosts in the northeastern United States, and to identify patterns of species distribution on hosts and among sites. Results indicated that Geastrumia polystigmatis was the predominant species on apples, whereas Peltaster species were more common on reservoir hosts. Species distribution varied among …

Examination Of The Association Between In Vitro Propiconazole Sensitivity And Field Efficacy Among Five Diverse Sclerotinia Homoeocarpa Populations On Turfgrass, James T. Popko Jr.

Masters Theses 1911 - February 2014

Sclerotinia homoeocarpa F.T. Bennett, the causal agent associated with dollar spot, is a common and economically challenging turfgrass disease in North America. Acceptable turfgrass quality requires the optimization of cultural practices and the judicious use of fungicides. Sclerotinia homoeocarpa causes significant damage to turfgrass swards from May to October annually, therefore, requiring multiple fungicide applications to maintain satisfactory turfgrass quality throughout the growing season. Sterol demethylation inhibitor (DMI) fungicides are among the most widely used in the United States and frequent use has led to the development of fungicide resistance to the DMI fungicide class. The precise mechanism of DMI …

Spring 1985, Chris Beasley, James Beard, Robert N. Carrow, Chuck Wilson

Turf Bulletin

1. The New England Sod Industry (page 3)
2. New Trends and Research in Turfgrass Culture (5)
3. Fifty-Fourth Annual Turf Conference and Ninth Industrial Show
4. Irrigation Programming (13)
5. Landscape Development in Large Residential Communities (17)

Spring 1984 Conference Issue, William A. Torello, Anna G. Symington, Charles F. Mancino, Elizabeth L. Clifton, Lesley A. Spokas, Joseph Troll, John M. Zak, Peter H. Dernoeden

Turf Bulletin

1. Research Update (page 3)
2. Low Management Kentucky Bluegrass Cultivar Trials (5)
3. Nitrogen Leaching Losses from N Fertilizer Applied to Turf (8)
4. Fifty-third Annual Turf Conference and Eighth Industrial Show (10)
5. Liquid Versus Dry Nitrogren Fertilizer Applications on Kentucky Bluegrass (13)
6. Growth Retardant, Embark (16)
7. Fungicides: The Good, The Bad and The Ugly (18)

Spring 1983 Conference Issue, Anna G. Symington, Mickey Spokas, Joseph Troll, Nancy L. Garrabrants, David K. Bell

Turf Bulletin

1. Chemical Retardation of Grass Growth (page 3)
2. Cultivar Trials - 1982 (5)
3. Fifty-second Annual Turf Conference and Seventh Industrial Show (10)
4. Dollar Spot Fungicide Control Trials - 1982 (13)
5. Winter Protection of Herbaceous Perennials (14)
6. Control of Annual Bluegrass in Golf Tees Using Perennial Ryegrass and Ethofumesate (15)

Fall 1983, Pat Lucas, Ann Reilly, J. D. Butler, C. M. Feldhake, R. H. Hurley, C. Reed Funk, Prasanta C. Bhowmik, Roy L. Goss

Turf Bulletin

1. Canada Geese Control (page 3)
2. Coloring the Course (5)
3. Irrigation's Role for Turf and Landscape (7)
4. Perennial Ryegrass Update (12)
5. Crabgrass - A Common Troublesome Weed in Turfgrass (15)
6. Thatch and Its Control (18)

Spring 1982 Conference Issue, Nancy N. Ragsdale, William A. Torello, William B. Davis, Jack A. Paul

Turf Bulletin

1. Turf Clippings (page 3)
2. How the RPAR Process is Working (4)
3. Cellular and Genetic Engineering Techniques Applied Towards the Improvement of Turfgrass (7)
4. Fifty-First Annual Turf Conference and Sixth Industrial Show (10)
5. Natural Versus Artificial Turf--an Economical Alternative (13)
6. Fertility Assay of Sands (17)

Fall 1982, Roland D. Hauck, Anne Moffat, Roger Funk

Turf Bulletin

1. Turf Clippings (page 3)
2. Using Nitrogen Efficiently - Theoretical Aspects (4)
3. Life After Frost (12)
4. Liability and The Lawn Care Industry (16)

Summer 1982, Patricia J. Vittum, J. M. Vargas Jr., Joseph Troll, Mickey Spokas, David F. Karnosky, Clive G. Jones

Turf Bulletin

1. Registration of Isofenphos (page 3)
2. Managing Annual Bluegrass (4)
3. Helminthosporium Leaf Spot Fungicide Control Trial--1981 (8)
4. Cultivar Trials--1981 (9)
5. Dollar Spot (Sclerotinia Homeocarpa Sp.) Fungicide Control Trial--1981 (14)
6. Living with the Gypsy Moth (15)

Spring 1981 Conference Issue, Ruth S. Zak, Daniel Hillel, Joseph Troll

Turf Bulletin

1. Fifty Years of Turf Management Education at the University of Massachusetts (page 3)
2. Commentary: A Case for Conditional Optimism (7)
3. Fiftieth Annual Turf Conference and Fifth Industrial Show (10)
4. Dollar Spot Fungicide Trials --1980 (12)
5. Tree News (14)
6. Insurance Requirements (16)
7. UMass Turfgrass Research Fund (18)
8. Exams (19)

Summer 1981, Ellery L. Knake, T. L. Larry, J. F. Wilkinson, R. H. Miller, Carol A. Lembi, Ted Horton, Horace Ames

Turf Bulletin

1. Editorial (page 3)
2. Results of Field Test to Study Human Exposure to 2,4,5,-T Application (4)
3. Investigation and Treatment of Localized Dry Spots on Sand Golf Greens (6)
4. Aquatic Weed Control- In Review (11)
5. Golf Course Superintendent - A Perspective (14)
6. Four Seasons Ground Maintenance (16)

Fall 1981, Patricia J. Vittum, Dan Paulson Jr., Bob Early, Elmer R. Fleck

Turf Bulletin

1. Turf Clippings (page 3)
2. Registration of Oftanol^R (Isofenphos) (4)
3. Effect of pH Organic Matter and Solid Texture on Herbicides (6)
4. Lawn Care: Big Potential for Fluids

Summer 1980, K. A. Hurto, Ruth Foster

Turf Bulletin

1. Principles of Turfgrass Weed Control III. Broadleaf Weeds (page 3)
2. To Stop Leaks, First Find Them (6)
3. Turgrass Research Field Day (9)
4. Gypsy Moth (10)
5. Try Ground Covers for Low-Maintenance (13)
6. Pesticide News (18)

Fall 1980, Alan Bebka, Alfred W. Boicourt, Robert N. Carrow, James O'Kelly

Turf Bulletin

1. Chronic Organo-Phosphate Poisoning (page 3)
2. Perennials (7)
3. Topdressing (10)
4. Winter Problems of Shade Trees (15)
5. Fall Color (18)

Spring 1980 Conference Issue, John O'Connor, William A. Meyer

Turf Bulletin

1. Plastic Water Pipe: How Well Does it Hold Up? (page 3)
2. Forty-Ninth Annual Turf Conference and Fourth Industrial Show Program (10)
3. Blend Bluegrasses for Best Disease Resistance (13)
4. Dollar Spot Fungicide Trials--1979 (16)
5. UMass Turfgrass Research Fund (18)

Spring 1979 Conference Issue, K. A. Hurto, Alfred W. Boicourt, W. A. Sinclair, E. S. Pira

Turf Bulletin

1. Principles of Turfgrass Weed Control Annual Grasses (page 3)
2. Bean-Shape Islands (7)
3. High Protein Food From Grass (8)
4. Forty-Eighth Annual Turf Conference and Third Industrial Show Program (10)
5. "Dutch Elm Disease: Perspectives After 60 Years" (13)
6. Toro Irrigation Design Seminar (14)
7. Ideas: New and Old (15)
8. More Pesticide Exams (16)
9. Disposal of Pesticides in Massachusetts (18)
10. Moth Controls Nutsedge Weeds (19)
11. New Pesticide Bill (20)

Fall 1979, Walter C. Shortle, Jeff Cox, Francis W. Holmes, Clifford S. Chater, Anthony Decrosta

Turf Bulletin

1. New Ideas in Tree Care (page 3)
2. 'Wonder Water' (6)
3. Herbicides: Are They Safe? (9)
4. University of Massachusetts Turfgrass Field Day (10)
5. The Shade Tree Laboratories of Massachusetts--Origin and Public Services (11)
6. Do Pesticides Cause Allergies (14)
7. Federal Noxious Weed Act Funded (18)
8. Your Opinion Please (18)

Summer 1979, Joseph Troll, K. A. Hurto

Turf Bulletin

1. Fertilizer Programs for Bluegrass and Ryegrasses (page 3)
2. Turfgrass Slide Sets Available (6)
3. Seed Extracts Repel Japanese Beetles (8)
4. Principles of Turfgrass Weed Control (10)
5. How Regulation is Impacting on Pesticide Research (12)
6. UMass Turfgrass Research Fund (20)
7. UMass Turfgrass Research Field Day (20)

Winter 1979, John Tristan, Joe Don Boyd, Fred P. Miller, K. A. Hurto, Pat Kristy, Joseph Troll

Turf Bulletin

1. Clubhouse Plants (page 3)
2. Massachusetts Pesticide News (6)
3. The Alsea Report on 2,4,5-T (8)
4. Better Pest Control (10)
5. Acid Rain: Something Else to Worry About? (11)
6. UMass Turfgrass Research Update (13)
7. 1979 Preemergence Crabgrass Control Trial

Spring 1987 Conference Issue, Brian M. Silva, J. Troll, M. Bryant, Richard Dattner

Turf Bulletin

1. Phosphorus and Its Effect on Plant Growth (page 3)
2. Dollar Spot Fungicide Control Trial--1977 (9)
3. Forty-Seventh Annual Turf Conference and Second Industrial Show Program (10)
4. Parks for the Year 2000 (15)