Phyllosphere microbial diversity and specific taxa mediate within-cultivar resistance to in cacao.

The oomycete pathogen , which causes black pod rot (BPR) on cacao ( L.), is responsible for devastating yield losses worldwide. Genetic variation in resistance to spp.

Molecular Identification of Mutations Conferring Resistance to Azoxystrobin in .

, the causal agent of frogeye leaf spot (FLS) of tobacco, has been exposed to quinone outside inhibitor (QoI) fungicides for more than a decade through azoxystrobin applications targeting other major foliar diseases. From 2016 to 2018, a total of 124 isolates were collected from tobacco fields throughout Kentucky. Sensitivity of these isolates to azoxystrobin was previously characterized by determining the effective concentration to inhibit 50% conidial germination (EC).

Mutations F129L and G143A Confer Resistance to Azoxystrobin in , the Frogeye Leaf Spot Pathogen of Tobacco.

Azoxystrobin is the only synthetic, systemic fungicide labeled in the United States for management of frogeye leaf spot (FLS) of tobacco ( L.), caused by . Though traditionally considered a minor disease in the United States, FLS has recently become yield and quality limiting.

Environmental and Management Factors Associated with Bacterial Diseases of Onion in Pennsylvania.

Bacterial diseases of onion may result in over 60% yield loss in crops grown in the Mid-Atlantic region, even when managed with recommended chemical and cultural practices. To identify environmental and production factors associated with the high incidence of bacterial rots in Pennsylvania, data on 32 environmental and management variables ranging from soil temperature to foliar nutrients were recorded during three visits to each of 28 and 26 fields, surveyed in 2011 and 2012, respectively. Multiple linear regression indicated negative relationships between foliar nitrogen and carbon at midseason and total incidence of bacterial rots.

The fire blight pathogen Erwinia amylovora requires the rpoN gene for pathogenicity in apple.

RpoN is a σ(54) factor regulating essential virulence gene expression in several plant pathogenic bacteria, including Pseudomonas syringae and Pectobacterium carotovorum. In this study, we found that mutation of rpoN in the fire blight pathogen Erwinia amylovora caused a nonpathogenic phenotype. The E.

Orchard factors associated with resistance and cross resistance to sterol demethylation inhibitor fungicides in populations of Venturia inaequalis from Pennsylvania.

Orchard management practices, such as destroying of overwintered inoculum and limiting the number of fungicide applications, are often recommended as tactics for slowing the development of resistance to sterol demethylation-inhibitor (DMI) fungicides in populations of Venturia inaequalis. However, there is little quantitative evidence relating the use of such practices to levels of resistance in orchards. The aim of this study was to evaluate the sensitivity of V.

2,4-diacetylphloroglucinol alters plant root development.

Pseudomonas fluorescens isolates containing the phlD gene can protect crops from root pathogens, at least in part through production of the antibiotic 2,4-diacetylphloroglucinol (DAPG). However, the action mechanisms of DAPG are not fully understood, and effects of this antibiotic on host root systems have not been characterized in detail. DAPG inhibited primary root growth and stimulated lateral root production in tomato seedlings.