[3] P. pyrinus is the causitive agent of brown leaf spot disease of pear trees.

[1] The cause of brown leaf spot disease affecting pear trees in South Korea was first identified as a novel bacterial infection in 1990.

The proposed name for the species was Erwinia pirina, but this name was not validly published.

[4][1] In 1993, further research grouped the organism in the genus Enterobacter as E.

[2] The species name is derived from the Greek word pŷr, which means pear.