부산대학교 도서관

An incidental fruit rot of oriental pears occurred in Chung Liao, Nantou in July, 1998. The causal agent attacked fruits and caused severe fruit rot. After being attacked, fruits firstly showed water-soaked lesions, the tissues became extremely soft, followed by a slimy decay that associated with mushy slimy white color ooze emerging from lesions. An unknown bacterium was isolated from the diseased fruits and followed identification based on physiological characteristcs, Biolog analyses and primer pairs specific to Erwinia carotovora and Erwinia chrysanthemi using polymerase chain reaction, the causal agent was therefore identified as Erwinia carotovora subsp. carotovora (Ecc). Inoculation tests conducted in the laboratory indicated that the expansion of the soft lesion could reach up to 1.2 cm diameter per day. In addition to pear, the bacterium could also cause soft rot of potato, carrot, onion and tobacco. Transmission tests combining oriental fruit flies and Ecc in a confined space indicated that oriental fruit flies could transmit the disease through feeding or egg laying. Screening eleven chemicals include Streptomycin + Tetracycline, Tetacycline, Streptomycin, Thiophanate methy1 + Streptomycin, Kasugamycin, Kasugamyucin + Copper oxychloride, Copper hydroxide, Copper oxychloride, Copper oxychloride + Mancozeb, and Mancozeb in vitro, the results showed that all chemicals, except Zineb, effectively inhibited bacterial growth at various dosage tested.