First Report of Erwinia aphidicola Causing Bulb Rot of Onion in Chile

During the 2021-22 and 2022-23 seasons (December to February), onion plants (Allium cepa L.) showing decay, leaf blight, chlorosis and water soak lesions were collected in Central Chile. Five symptomatic plants were sampled from 20 different onion fields. Brown rot of the external scales was observed in bulbs from two fields: one planted with the cv. Campero (20 ha; O'Higgins Region), and another with cv. Marenge (2 ha; Metropolitan Region). The disease incidence in these fields ranged from 2% to 5%. Isolations were carried out from symptomatic leaves and bulbs from these fields on King's B medium, resulting in small white colonies with smooth margin. Three isolates were selected, two from first field (QCJ3A & QCJ2B), and one from second field (EPB1). A preliminary identification based on 16S rRNA sequences was conducted. BLAST analyses of strains QCJ3A, QCJ2B and EPB1 (GenBank Accession No. PP345601 to PP345603) against the NCBI Database resulted in a match with strains (GenBank Accession No. ON255770.1 and ON255825.1) isolated from infected bulbs in Texas, USA identified as