A5066746626- Plant Pathogens and Fungal Diseases
- Horticultural and Viticultural Research
- Plant and Fungal Interactions Research
- Plant Pathogenic Bacteria Studies
- Insect-Plant Interactions and Control
- Yeasts and Rust Fungi Studies
- Plant Virus Research Studies
- Powdery Mildew Fungal Diseases
- Fungal Plant Pathogen Control
- Banana Cultivation and Research
- Plant-Microbe Interactions and Immunity
- Hemiptera Insect Studies
- Plant Pathogens and Resistance
- Plant Disease Management Techniques
- Legume Nitrogen Fixing Symbiosis
- Berry genetics and cultivation research
- Mycorrhizal Fungi and Plant Interactions
- Phytoplasmas and Hemiptera pathogens
- Forest Insect Ecology and Management
- Mycotoxins in Agriculture and Food
- Cocoa and Sweet Potato Agronomy
- Plant Disease Resistance and Genetics
- Cassava research and cyanide
- Plant Physiology and Cultivation Studies
- Plant tissue culture and regeneration
Virginia Tech
2014-2023
Virginia Cooperative Extension
2011-2023
Shinshu University
2023
Kansas State University
2007-2009
Pennsylvania State University
2007
The Ohio State University
2000-2006
College of Wooster
2002-2003
To gain insights into the virulence suppressive mechanism of a nonpathogenic strain Rhizobium vitis ARK-1, we co-inoculated ARK-1 with tumorigenic (Ti) R. to examine expression two essential genes (virA and virG) one non-essential gene (virD3) Ti at wound site grapevine.Co-inoculation VAT03-9 1:1 cell ratio grapevine shoots resulted in significantly lower virA, virD3, virG 1 day after inoculation compared those when were inoculated only VAT03-9. was not able catabolize acetosyringone, which...
Six different individuals (raters) assessed the severity of Phomopsis leaf blight on strawberry leaflets in five experimental repetitions over 2 years by making a direct visual estimation percentage diseased area each leaflet or using Horsfall-Barratt (H-B) disease scale. Intra-rater and inter-rater reliability accuracy were determined, then relationship between visually estimated values actual was evaluated. Agreement assessment times same raters (i.e., intra-rater reliability), agreement...
The putative center of origin Plasmopara viticola, the causal agent grape downy mildew, is eastern North America, where it has been described on several members family Vitaceae (e.g., Vitis spp., Parthenocissus and Ampelopsis spp.). We have completed first large-scale sampling P. viticola isolates across a range wild cultivated host species distributed throughout above region. Sequencing results four partial genes indicated presence new vulpina in Virginia, adding to cryptic recently...
Mealybugs (Hemiptera: Pseudococcidae) are one of the prevalent pests infesting wine grapes in eastern United States. Their close association with ants (Hymenoptera: Formicidae) provides them protection against natural enemies. In this paper, we present our research on identification mealybug species and ant genera around vineyard effect use sugar dispensers populations fruit cluster infestations. Field trials were carried out two commercial vineyards Virginia, States, a history The without...
Phytophthora root and stem rot of soybeans caused by sojae is a serious limitation to soybean production in the United States. Partial resistance P. effective against all races pathogen form incomplete which level colonization reduced following inoculation. Other forms include single dominant gene Rps2 Ripley's resistance, are both race-specific. To differentiate partial from other types components lesion length, numbers oospores, infection frequency were measured eight genotypes inoculated...
Diseased individuals (e.g., leaves, plants) typically are clustered in nature, resulting greater heterogeneity or variability of disease incidence than would be expected for a random pattern. To account this variability, as well the binary nature and multiple sources variation designed experiments, generalized linear mixed model (GLMM) can used to analyze collected data. GLMMs becoming more common many disciplines may preferred over analysis variance non-normally distributed We evaluated...
We investigated the prevalence of viruses infecting grapevines in Virginia, identity disease vectors, and potential factors affecting virus incidence. Tested were grapevine leafroll-associated (GLRaV-1 -4), fleck (GFkV), A (GVA), B (GVB), rupestris stem pitting-associated (GRSPaV), tomato ringspot (ToRSV), vein clearing (GVCV), red blotch (GRBV), Pinot gris (GPGV). documented wide distributions GRSPaV (54%) GRBV (24%) common occurrences grape (Pseudococcus maritimus) Gill’s (Ferrisia gilli)...
Exclusion cages were used to compare the incidence and severity of feeding injury from brown marmorated stink bug, Halyomorpha halys (Stål) (Hemiptera: Pentatomidae), on 'Redhaven' peaches, 'Golden Delicious' apples, 'Smoothee Golden' apples at harvest, following sequential periods exposure natural H. populations during 2011 2012 growing seasons in Virginia. The fruit these experiments orchards or trees that not managed for halys. Treatments sets 50 always caged, never exposed one interval...
Crown gall of grapevine, which is caused by tumorigenic Rhizobium vitis, the most important bacterial disease grapevine throughout world. Screening tests biological control agents resulted in discovery a nonpathogenic R. vitis strain ARK-1. By soaking roots with cell suspension ARK-1 prior to planting field, treatment significantly reduced number plants crown symptoms. Several field trials result indicated that was very useful not only for but also various other plant species. In experiments...
A statewide survey for incidence of Phomopsis cane and leaf spot grape (caused by viticola) was conducted during the 2002 to 2004 growing seasons. Over 3 years, disease observed in all surveyed vineyards, mean leaves internodes 42 50%, respectively. hierarchical linear mixed model used evaluate effects region, farm within vineyard farm, sampling site (i.e., vine) vineyard, shoot cane) vine on incidence. Region state did not have a significant effect but there variation at other levels...
Early disease detection is a prerequisite for enacting effective interventions control. Strains of the bacterial plant pathogen Xylella fastidiosa have recurrently spread to new crops in countries causing devastating outbreaks. So far, investigation outbreak strains and highly resolved phylogenetic reconstruction required whole-genome sequencing pure cultures, which are challenging obtain due fastidious nature X. . Here, we show that culture-independent metagenomic sequencing, using Oxford...
Spring dead spot (SDS) (
A field evaluation of a warning system for Phomopsis cane and leaf spot grape (Vitis spp.), caused by viticola, was conducted in Ohio over 3 years (2002 to 2004) applying fungicides fungicide-adjuvant combinations based on predicted infection events. Three different criteria risk-light, moderate, high-were evaluated with the system. The is measured weather conditions (temperature wetness duration following rain) model risk internode infection. Vines were sprayed either or calendar-based...
Efficacy of application the fungicides calcium polysulfide or fixed copper during dormant period on control Phomopsis cane and leaf spot grape (Vitis spp.), caused by viticola, was examined under field conditions 2003 2004 growing seasons in Ohio. Dormant-period fungicide applications were made either fall (after drop periderm tissue formation first-year canes, mid-November), spring (at bud-swell, mid-April), both. Disease incidence severity leaves internodes examined. In addition, effects...
Abstract Spatial patterns of incidence Phomopsis cane and leaf spot were examined using 57 data sets obtained from a statewide survey grape vineyards in Ohio 2002–2004. To characterize small‐scale at the vine scale or below, discrete‐distributional analyses used to quantify heterogeneity disease within vineyards. The number diseased leaves internodes (out 15) per sampling unit was better fitted by beta‐binomial than binomial distribution 67% 91% cases, respectively. index aggregation...
Global travel and trade in combination with climate change are expanding the geographic distribution of plant pathogens. The bacterium Xylella fastidiosa is a prime example. Native to Americas, it has spread Europe, Asia, Middle East. To assess risk that pathogen introductions pose crops newly invaded areas, key survey their diversity, host range, disease incidence relation climatic conditions where they already present. We performed X. grapevine Virginia using quantitative PCR, multilocus...