Species of and Isolated during an Outbreak of Blackleg and Soft Rot of Potato in Northeastern and North Central United States.

An outbreak of bacterial soft rot and blackleg of potato has occurred since 2014 with the epicenter being in the northeastern region of the United States. Multiple species of and are causal agents, resulting in losses to commercial and seed potato production over the past decade in the Northeastern and North Central United States. To clarify the pathogen present at the outset of the epidemic in 2015 and 2016, a phylogenetic study was made of 121 pectolytic soft rot bacteria isolated from symptomatic potato; also included were 27 type strains of and species, and 47 historic reference strains.

Phylogenomic Analysis of a 55.1-kb 19-Gene Dataset Resolves a Monophyletic that Includes the Species Complex.

Scientific communication is facilitated by a data-driven, scientifically sound taxonomy that considers the end-user's needs and established successful practice. In 2013, the community voiced near unanimous support for a concept of that represented a clade comprising all agriculturally and clinically important species, including the species complex (FSSC). Subsequently, this concept was challenged in 2015 by one research group who proposed dividing the genus into seven genera, including the FSSC described as members of the genus , with subsequent justification in 2018 based on claims that the 2013 concept of is polyphyletic.

Genetic Differentiation of Populations Recovered from Symptomatic and Asymptomatic Hosts.

is a soilborne fungal pathogen affecting many economically important crops that can also infect weeds and rotational crops with no apparent disease symptoms. The main research goal was to test the hypothesis that populations recovered from asymptomatic rotational crops and weed species are evolutionarily and genetically distinct from symptomatic hosts. We collected isolates from symptomatic and asymptomatic hosts growing in fields with histories of Verticillium wilt of potato in Israel and Pennsylvania (United States), and used genotyping-by-sequencing to analyze the evolutionary history and genetic differentiation between populations of different hosts.

Factoring Ecological, Societal, and Economic Considerations into Inoculant Development.

There are many paths toward effective microbial inoculants for agriculture. Considering what is practical for the present day technological and farming landscape should not limit our creativity in developing innovative technologies. However, factors including production costs, practicality of implementation, and technology adoption by farmers will drive the success of new management approaches.

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.

Genetic Variation within Clonal Lineages of Phytophthora infestans Revealed through Genotyping-By-Sequencing, and Implications for Late Blight Epidemiology.

Genotyping-by-sequencing (GBS) was performed on 257 Phytophthora infestans isolates belonging to four clonal lineages to study within-lineage diversity. The four lineages used in the study were US-8 (n = 28), US-11 (n = 27), US-23 (n = 166), and US-24 (n = 36), with isolates originating from 23 of the United States and Ontario, Canada. The majority of isolates were collected between 2010 and 2014 (94%), with the remaining isolates collected from 1994 to 2009, and 2015.

An ephemeral sexual population of Phytophthora infestans in the Northeastern United States and Canada.

Phytophthora infestans, the causal agent of late blight disease, has been reported in North America since the mid-nineteenth century. In the United States the lack of or very limited sexual reproduction has resulted in largely clonal populations of P. infestans.

Highly diverse endophytic and soil Fusarium oxysporum populations associated with field-grown tomato plants.

The diversity and genetic differentiation of populations of Fusarium oxysporum associated with tomato fields, both endophytes obtained from tomato plants and isolates obtained from soil surrounding the sampled plants, were investigated. A total of 609 isolates of F. oxysporum were obtained, 295 isolates from a total of 32 asymptomatic tomato plants in two fields and 314 isolates from eight soil cores sampled from the area surrounding the plants.

Hidden host plant associations of soilborne fungal pathogens: an ecological perspective.

Much of the current knowledge on population biology and ecology of soilborne fungal pathogens has been derived from research based on populations recovered from plants displaying disease symptoms or soil associated with symptomatic plants. Many soilborne fungal pathogens are known to cause disease on a large number of crop plants, including a variety of important agronomical, horticultural, ornamental, and forest plants species. For instance, the fungus Verticillium dahliae causes disease on >400 host plants.

Discriminatory simplex and multiplex PCR for four species of the genus Sclerotinia.

Sclerotinia sclerotiorum (Lib.) de Bary, S. minor Jagger, S.