Survival of on Common Materials.

causes strawberry angular leaf spot (ALS), an important disease for the strawberry nursery industry in North America. To identify potential inoculum sources, the survival of was examined on the surfaces of 11 common materials found in nurseries: corrugated cardboard, cotton balls, cotton cloth (t-shirt), strawberry leaf, sheet metal, plastic, rubber, Tyvek, wood (balsa), glass (microscope slide), and latex (latex glove). Prefabricated rectangular samples (7.

A Long-Amplicon Viability-qPCR Test for Quantifying Living Pathogens that Cause Bacterial Spot in Tomato Seed.

Bacterial spot is one of the most serious diseases of tomato. It is caused by four species of , , , and . Contaminated or infected seed can be a major source of inoculum for this disease.

Broad Resistance to Post-Harvest Fruit Rot in USVL Watermelon Germplasm Lines to Isolates of Across the United States.

Watermelon is an important cucurbit vegetable crop grown in most of the United States. Phytophthora fruit rot of watermelon caused by has been a major factor, limiting production for the past 15 years in the southeastern United States. The U.

Draft Genome Sequences of Two Xanthomonas fragariae Strains.

is the causal agent of angular leaf spot of strawberry. Short-read sequences were generated for two strains with different virulence phenotypes on the Illumina HiSeq 2000 platform. These genome sequences will contribute to a better understanding of pathogen evolution and the genes contributing to virulence in .

A Maximum Dose Bioassay to Assess Efficacy of Key Insecticides Against Bemisia tabaci MEAM1 (Hemiptera: Aleyrodidae).

The whitefly, Bemisia tabaci MEAM1 Gennadius causes serious losses to Florida vegetable and ornamental production. In 2019, a maximum dose bioassay was administered to 20 field populations of B. tabaci MEAM1 collected from various economic and weed hosts across south Florida to assess insecticide efficacy.

Complete genome sequence of Xanthomonas phage RiverRider, a novel N4-like bacteriophage that infects the strawberry pathogen Xanthomonas fragariae.

Xanthomonas phage RiverRider is a novel N4-like bacteriophage and the first phage isolated from the plant pathogen Xanthomonas fragariae. Electron microscopy revealed a Podoviridae morphology consisting of isometric heads and short noncontractile tails. The complete genome of RiverRider is 76,355 bp in length, with 90 open reading frames and seven tRNAs.

Detection of Viable Cells in Strawberry Using Propidium Monoazide and Long-Amplicon Quantitative PCR.

causes angular leaf spot in strawberry. The pathogen's association with its host tissue is thought to be a condition for its survival. Consequently, transmission of the pathogen to field production sites occurs almost exclusively through the movement of contaminated planting stock.

Spatial and Temporal Physiognomies of Whitefly and Tomato Yellow Leaf Curl Virus Epidemics in Southwestern Florida Tomato Fields.

Epidemics of tomato yellow leaf curl virus (TYLCV; species ) have been problematic to tomato production in the southeastern United States since the first detection of the virus in Florida in the late 1990s. Current strategies for management focus on farm-centric tactics that have had limited success for controlling either TYLCV or its whitefly vector. Areawide pest management (AWPM)-loosely defined as a coordinated effort to implement management strategies on a regional scale-may be a viable management alternative.

Development of Phytophthora Fruit Rot Caused by Phytophthora capsici on Resistant and Susceptible Watermelon Fruit of Different Ages.

Watermelon is an important crop grown in 44 states in the United States. Phytophthora fruit rot caused by Phytophthora capsici is a serious disease in the southeastern U.S.

Risk Factors for Bud Perennation of Podosphaera macularis on Hop.

The hop powdery mildew fungus Podosphaera macularis persists from season to season in the Pacific Northwestern United States through infection of crown buds because only one of the mating types needed to produce the ascigerous stage is presently found in this region. Bud infection and successful overwintering of the fungus leads to the emergence of heavily infected shoots in early spring (termed flag shoots). Historical data of flag shoot occurrence and incidence in Oregon and Washington State during 2000 to 2017 were analyzed to identify their association with the incidence of powdery mildew, growers' use of fungicides, autumn and winter temperature, and other production factors.

Colonization and Movement of Xanthomonas fragariae in Strawberry Tissues.

Xanthomonas fragariae causes angular leaf spot of strawberry, an important disease in strawberry growing regions worldwide. To better understand how X. fragariae multiplies and moves in strawberry plants, a green fluorescent protein (GFP)-labeled strain was constructed and used to monitor the pathogen's presence in leaf, petiole, and crown tissue with fluorescence microscopy following natural and wound inoculation in three strawberry cultivars.

Analysis of the Spatial Pattern of Strawberry Angular Leaf Spot in California Nursery Production.

In California, angular leaf spot (ALS) is a common disease in strawberry nursery production, and a major concern for nurseries wishing to export plants. As the spatial pattern of a disease can offer insight into pathogen source, mode of dissemination, and how current crop management practices affect epidemic development, an understanding of the spatial pattern of ALS would allow nursery growers to make informed decisions regarding disease management. Ninety-seven field assessments of disease incidence were performed at different nursery locations in 2014 and 2015 to quantify ALS spatial pattern under commercial conditions.

Development and Evaluation of ELISA and qRT-PCR for Identification of Squash vein yellowing virus in Cucurbits.

Squash vein yellowing virus (SqVYV) causes viral watermelon vine decline. To facilitate detection of SqVYV, enzyme linked-immunosorbent assay (ELISA) and quantitative reverse-transcription polymerase chain reaction (qRT-PCR) diagnostic methods were developed. Both methods were capable of detecting SqVYV in a wide range of cucurbit hosts.

Genomic and Biological Characterization of Tomato necrotic streak virus, a Novel Subgroup 2 Ilarvirus Infecting Tomato in Florida.

Genomic and biological characterization of Tomato necrotic streak virus (TomNSV), a recently described ilarvirus infecting tomato in Florida, was completed. The full genome sequence revealed that TomNSV is a novel subgroup 2 ilarvirus that is distinct from other previously reported tomato-infecting ilarviruses: Tobacco streak virus, Parietaria mottle virus, and Tomato necrotic spot virus included in subgroup 1. In a host range experiment, TomNSV infected members of the Solanaceae and Chenopodiaceae plant families but did not infect sunflower (Helianthus annuus L.

A Loop-Mediated Isothermal Amplification Assay and Sample Preparation Procedure for Sensitive Detection of Xanthomonas fragariae in Strawberry.

Xanthomonas fragariae is a bacterium that causes angular leaf spot of strawberry. Asymptomatic infection is common and contributes to the difficulties in disease management. The aim of this study was to develop a loop-mediated isothermal amplification (LAMP) assay as an efficient method for detection of asymptomatic infections of X.

Spatial and Temporal Analysis of Squash vein yellowing virus Infections in Watermelon.

Squash vein yellowing virus (SqVYV) is a whitefly-transmitted ipomovirus infecting watermelon and other cucurbits that was recently introduced to Florida. Effects on watermelon are devastating, with total vine collapse, often near harvest, and fruit rendered unmarketable by brown, discolored flesh. The epidemiology of SqVYV was studied in a 1-ha field of 'Fiesta' watermelon over six growing seasons (I to VI) to characterize the spatial patterning of disease and temporal rate of disease progress, as well as its association with Cucurbit leaf crumple virus (CuLCrV) and Cucurbit yellow stunting disorder virus (CYSDV), two additional whitefly-transmitted viruses that often occur with SqVYV.

Emergence of Groundnut ringspot virus and Tomato chlorotic spot virus in Vegetables in Florida and the Southeastern United States.

Groundnut ringspot virus (GRSV) and Tomato chlorotic spot virus (TCSV) are two emerging tospoviruses in Florida. In a survey of the southeastern United States, GRSV and TCSV were frequently detected in solanaceous crops and weeds with tospovirus-like symptoms in south Florida, and occurred sympatrically with Tomato spotted wilt virus (TSWV) in tomato and pepper in south Florida. TSWV was the only tospovirus detected in other survey locations, with the exceptions of GRSV from tomato (Solanum lycopersicum) in South Carolina and New York, both of which are first reports.

Physiological Effects of Squash vein yellowing virus Infection on Watermelon.

Squash vein yellowing virus (SqVYV) is the cause of viral watermelon vine decline. The virus is whitefly-transmitted, induces a systemic wilt of watermelon plants, and causes necrosis and discoloration of the fruit rind. In the field, SqVYV is often detected in watermelon in mixed infections with other viruses including the aphid-transmitted Papaya ringspot virus type W (PRSV-W).

Squash vein yellowing virus Infection of Vining Cucurbits and the Vine Decline Response.

The responses of a diverse group of vining cucurbits to inoculation with Squash vein yellowing virus (SqVYV) were determined. For the first time, Cucurbita maxima, Cucumis dipsaceus, and Cucumis metuliferus were observed to develop necrosis and plant death similar to the SqVYV-induced vine decline in watermelon (Citrullus lanatus var. lanatus).

The use of latent class analysis to estimate the sensitivities and specificities of diagnostic tests for Squash vein yellowing virus in cucurbit species when there is no gold standard.

Squash vein yellowing virus (SqVYV) is the causal agent of viral watermelon vine decline, one of the most serious diseases in watermelon (Citrullus lanatus L.) production in the southeastern United States. At present, there is not a gold standard diagnostic test for determining the true status of SqVYV infection in plants.

Considerations of scale in the analysis of spatial pattern of plant disease epidemics.

Scale is an important but somewhat neglected subject in plant pathology. Scale serves as an abstract concept, providing a framework for organizing observations and theoretical models, and plays a functional role in the organization of ecological communities and physical processes. Rich methodological resources are available to plant pathologists interested in considering either or both aspects of scale in their research.

Association of Spring Pruning Practices with Severity of Powdery Mildew and Downy Mildew on Hop.

Downy mildew (caused by Pseudoperonospora humuli) and powdery mildew (caused by Podosphaera macularis) are important diseases of hop in the Pacific Northwest United States, and cultural practices may affect the severity of both diseases. The association of spring pruning quality and timing with severity of downy mildew and powdery mildew was assessed through analysis of survey data collected from commercial hop yards in Oregon and Washington. Among 149 hop yards surveyed, the most common pruning method was chemical desiccation (48% of yards), mechanical pruning (23%), or a combination of these practices (15%).

Ecology and management of whitefly-transmitted viruses of vegetable crops in Florida.

A variety of fresh market vegetables, including watermelon and tomato are economically important crops in Florida. Whitefly-transmitted Squash vein yellowing virus (SqVYV) was first identified in squash and watermelon in Florida in 2005 and shown to cause a severe decline of watermelon vines as crops approach harvest. Florida is most economically impacted by SqVYV, although the virus has been detected more recently in Indiana and South Carolina.

Distribution of four viruses in single and mixed infections within infected watermelon plants in Florida.

Whitefly-transmitted Squash vein yellowing virus (SqVYV) and Cucurbit leaf crumple virus (CuLCrV) and aphid-transmitted Papaya ringspot virus type W (PRSV-W) have had serious impact on watermelon production in southwest and west-central Florida in the past 5 years. Tissue-blot nucleic acid hybridization assays were developed for simple, high-throughput detection of these three viruses as well as Cucurbit yellow stunting disorder virus (CYSDV), which was first reported in Florida in 2008. To determine virus distribution within plants, we collected 80 entire plants just before or during the harvest period in a systematic sample, 20 each on 11 April, 18 April, 26 April, and 3 May 2007, from a fruiting commercial watermelon field near Immokalee, FL showing symptoms of infection by SqVYV, CuLCrV, and PRSV-W and, possibly, CYSDV.

Screening molecules for control of citrus huanglongbing using an optimized regeneration system for 'Candidatus Liberibacter asiaticus'-infected periwinkle (Catharanthus roseus) cuttings.

Citrus huanglongbing is one of the most destructive diseases of citrus worldwide. The disease is associated with three different species of 'Candidatus Liberibacter', of which 'Ca. L.