Bacterial brown spot
Onion Center Rot Erwinia Ananas.jpg
Two onions showing signs of center rot caused by P. ananatis
Scientific Classification
Kingdom: Bacteria
Phylum: Proteobacteria
Class: Gamma Proteobacteria
Order: Enterobacteriales
Family: Enterobacteriaceae
Genus: Pantoea
Species: Pantoea ananatis
Brown spot

Center rot
Centre rot
Pantoea bacterial blight
Erwinia ananas
Erwinia ananatis corrig. Serrano (1928) (Approved Lists 1980)
Pantoea agglomerans

Pantoea ananas (Serrano 1928) Mergaert Et Al. 1993

Bacterial brown spot (Pantoea ananatis) is a Gram-negative bacteria of the family Enterobacteriaceae.



Foliar symptoms of center rot are typically observed as severe chlorosis or bleaching of one or more of the center leaves of infected onions. Infected leaves are usually collapsed and hang down beside the onion neck. In harvested bulbs, reddish, collapsed scales near the neck area have been associated with center rot. [1][2]


Some growers apply a regular application of a copper-based pesticide for center rot although some experts do not consider this an effective treatment. Growers avoid onion cultivars that have been documented to be more susceptible to center rot. Some growers plant varieties that mature earlier to reduce the risk of infection.[2]