Journal of Taiwan Agricultural Research

Author:Yu-Ping Liang, Chao-Jung Wu, Hui-Wen Tsai, and Hui-Fang Ni*

Abstract:

    Avocado branch canker disease has been reported in many avocado-growing countries, and is associated with several species in the Botryosphaeriaceae family. In Taiwan, the disease is widely distributed in the main avocado-producing regions, but the pathogens were still unidentified. Thirteen fungal isolates were obtained from necrotic avocado woody tissues from seven orchards located in different regions of Taiwan. Based on morphology and phylogenetic analyses of the internal transcribed spacer sequence and partial sequence of the translation elongation factor 1-α gene, the isolates were identified as either Lasiodiplodia theobromae or Lasiodiplodia pseudotheobromae. The optimal temperature for mycelial growth for both species was around 30℃. Both species were pathogenic to avocado stems and fruits, causing a whitish exudate at the inoculation site and necrosis on the stem, and black lesions on the fruit. To our knowledge, this is the first report characterizing avocado branch canker in Taiwan, which is different from temperate regions in major pathogenic species. The information obtained in this study will be helpful for understanding the epidemiology of the pathogens and establishing effective disease management strategies in avocado.

Key words:Avocado, Branch canker, Lasiodiplodia theobromae, Lasiodiplodia pseudotheobromae, Taiwan

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