Recent Publications

The origin of RNA interference (RNAi), the cell sentinel system widely shared among eukaryotes that recognizes RNAs and specifically degrades or prevents their translation in cells, is suggested to predate the last eukaryote common ancestor (138).

Early blight, caused by the fungus Alternaria solani, is one of the most economically important foliar diseases of potatoes worldwide. In this study, 217 tetraploid old and modern potato cultivars were evaluated for foliar resistance to early blight in field experiments in Pennsylvania in 2016 and 2017.

Penicillium spp. cause blue mold of stored pome fruit. These fungi reduce fruit quality and produce mycotoxins that are regulated for processed fruit products.

Plants and microorganisms have been interacting in both positive and negative ways for millions of years. They are also frequently infected with viruses that can have positive or negative impacts.

There are many nonpathogenic viruses that are maintained in a persistent lifestyle in plants. Plant persistent viruses are widespread, replicating in their hosts for many generations.

Bee viral ecology is a fascinating emerging area of research: viruses exert a range of effects on their hosts, exacerbate impacts of other environmental stressors, and, importantly, are readily shared across multiple bee species in a community. However, our understanding of bee viral communities is limited, as it is primarily derived from studies of North American and European Apis mellifera populations.

Canola is one of the most economically important crops in Canada, and the root and rhizosphere microbiomes of a canola plant likely impact its growth and nutrient uptake.

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.

We exposed 11 milkweed species to ozone within continuous stirred-tank reactor (CSTR) chambers in a greenhouse to determine species sensitivity and potential use as bioindicators to detect phytotoxic levels of ambient ozone.

Verticillium dahliae is a plant pathogenic fungus that reproduces asexually and its population structure is highly clonal.

Apple scab caused by Venturia inaequalis is the most destructive disease of apple worldwide. In this study, genetic diversity of 101 V. inaequalis isolates from cultivated apples and ornamental crabapples in Pennsylvania (PA, USA) was characterized using 14 microsatellite markers.

Some volatile compounds (VCs) play critical roles in intra- and inter-species interactions. To investigate roles of VCs in fungal ecology, we characterized how VCs produced by Verticillium, a group of broad host range soilborne fungal pathogens, affect plant growth and development.

Volatile compounds (VCs) produced by diverse microbes seem to affect plant growth, development and/or stress tolerance.

Impatiens necrotic spot orthotospovirus (INSV) can impact economically important ornamental plants and vegetables worldwide.

The role of herbivore-associated microbes in mediating plant–herbivore interactions has gained recent attention. We show that a parasitoid associated with its caterpillar host not only suppresses the immune system of the caterpillar but also suppresses the induced defenses of the caterpillar’s host plant.

Foliar fungicide use in hybrid maize in the United States was rare before 2000. The decade from 2000 to 2010 saw foliar fungicides increasingly applied to maize in the absence of appreciable disease pressure, a practice seemingly at odds with integrated pest management philosophy.

Pseudomonas is a large and diverse genus of Gammaproteobacteria. To provide a framework for discovery of evolutionary and taxonomic relationships of these bacteria, we compared the genomes of type strains of 163 species and 3 additional subspecies of Pseudomonas, including 118 genomes sequenced herein.

During the investigation of the sudden and early onset of yellowing, followed by mortality of American elm (Ulmus americana L.) trees at the USDA Forest Service Northern Research Station in Delaware, Ohio, a phytoplasma of the clover proliferation group (16SrVI) was detected as the putative causal agent of the disease outbreak.

Arugula (Eruca sativa) is a leafy crucifer that is grown in coastal California as a fresh market commodity in bagged salad mixes. In January 2016, a foliar disease developed on commercially produced arugula in the Salinas Valley (Monterey County).

Rhizobacteria promote plant growth and disease control. However, in crop management practices cultivar and environmental conditions may also interfere with diseases outcome.