The first report of a rot on Welsh onion (Allium fistulosum L.) caused by Burkholderia cepacia complex bacteria in Akita Prefecture, Japan

In July 2021 in Akita Prefecture, a light-brown water-soaked lesions appeared on Welsh onion starting where the green leaves diverged, then spreading outward, and extending as water-soaked stripes to the white pseudostem. Bacteria isolated from the lesions were considered to belong to the Burkholderia cepacia complex (Bcc). Based on their pathogenicity on Welsh onion, bacteriological properties and genetic characteristics, the isolates were identified as B. cepacia, B. cenocepacia and B. pyrrocinia. This is the first report of bacterial rot of Welsh onion caused by Bcc bacteria in Japan.