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Since 2002, papaya black rot has been spreading over several islands of Okinawa Prefecture, Japan. To devise a prevention strategy for the disease, microbiological research on the pathogen was conducted. Twelve strains were isolated from papaya infected with black rot showing symptoms such as water‐soaked lesions on stems and petioles, black spots on fruits, and rotted leaves turning yellow with necrotic spots. Through Koch's postulates, we confirmed that the isolated strains caused papaya black rot. Bacteriological assays showed that the strains have characteristics different from the type strains of Erwinia mallotivora, E. papayae, and E. psidii. Moreover, 16S rDNA sequence similarity searches showed that the isolated strains had less than 98.6% similarity with type strains. Additionally, phylogenetic analysis of 16S rDNA sequences suggested that the isolated strains were possibly a novel species belonging to the genus Erwinia, as the strains formed an independent cluster and had low sequence similarity with the type strains. Earlier studies indicated that papaya black rot is caused by E. cypripedii. Therefore, we propose to add the Erwinia sp. isolated in this study to the list of papaya black rot pathogens. [ABSTRACT FROM AUTHOR]

In July 2013, a severe postharvest rot of mango fruits (cv. Lippens), with symptoms identical to stem-end rot caused by Lasiodiplodia theobromae or Neofusicoccum parvum, was found in Okinawa Prefecture, Japan. From affected fruit, Diaporthe species were consistently isolated. The isolates reproduced the original symptoms in healthy mango fruits after inoculation and were re-isolated from the inoculated fruits. Based on morphology and a phylogenetic analysis of rDNA-ITS, CAL, H3, EF1-α, and TUB, the isolates were classified into two Diaporthe species (Clade I and Clade II). In terms of susceptibility to procymidone, a registered fungicide against mango stem-end rot in Japan, the two Diaporthe species were less sensitive than previously reported mango stem-end rot pathogens and had MIC and EC50 values higher than the standard concentration applied. [ABSTRACT FROM AUTHOR]