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.

Culture-Based Assessment of Microbial Communities in Soil Suppressive to Potato Common Scab.

A field in East Lansing, MI, showed a decline of potato common scab compared with an adjacent potato field. To confirm that the decline was due to biological factors, the soil was assayed. In the greenhouse, putative common-scab-suppressive soil (SS) was either treated with various temperatures or mixed with autoclaved SS at various ratios.

Microbial Communities Associated with Potato Common Scab-Suppressive Soil Determined by Pyrosequencing Analyses.

Potato common scab, caused by Streptomyces spp., is an annual production problem for potato growers, and not effectively controlled by current methods. A field with naturally occurring common scab suppression has been identified in Michigan, and confirmed to have a biological basis for this disease suppression.