The shoot soft rot of mulberry caused by Erwinia carotovora var. carotovora (JONES) DYE

Abstract

An unknown bacterial disease of the mulberry, which was discovered in Hyogo and Chiba prefectures in 1969, expanded its distribution year by year. In 1977, the disease was observed in sixteen prefectures of Japan.
The characteristic symptoms of the disease are the soft rot and non-sprouting of the overwintering shoot in early spring and the soft rot of the young shoot in middle or late spring. When the diseased mulberry shoot was cut back, the wounded portion of the stock exuded sap for more than two weeks. In general, the disease severity in the mulberry fields seems to correlate with the degree of intermediate-cutting.
Many bacterial isolates, which were collected from diseased mulberry in various localities and showed the pathogenicity, were identified as Erwinia carotovora var. carotovora (JONES) DYE on the basis of their pathogenicities to various plants, bacteriological characters, and serological reactions. This new disease was designated at “shoot soft rot disease of mulberry”.