Pathogenicity of five Botryosphaeriaceae species isolated from Tectona grandis (teak): the pathogenic potential of Lasiodiplodia species

Abstract

Botryosphaeriaceae species commonly cause cankers and diebacks on woody hosts widely threatening forests and plantations. In this study, pathogenicity tests on Tectona grandis were conducted for five Botryosphaeriaceae species, viz. Barriopsis tectonae, Dothiorella tectonae, Lasiodiplodia brasiliense, L. pseudotheobromae and Sphaeropsis eucalypticola. Detached and wounded T. grandis twigs were inoculated with 0.1 cm3 agar plugs cut from the margins of actively growing colonies. Lesion development was recorded seven days after inoculation. Two isolates of L. pseudotheobromae (MFLUCC 12-0772 and MFLUCC 12-0796) associated with cankers and dieback were significantly pathogenic on T. grandis. However, each of these isolates was found only in one site amongst the 35 sites surveyed. Three species, B. tectonae, D. tectonae and S. eucalypticola were not pathogenic on T. grandis. It is supposed that these species might act as endophytes or saprobes on T. grandis. Two saprobic isolates L. brasiliense (MFLUCC 11-0414) and L. pseudotheobromae (MFLUCC 12-0053) were likely to be potential pathogens. This is the first report of the pathogenic potential of saprobic L. brasiliense and L. pseudotheobromae on teak in Thailand. The possible reasons for lesions caused by these two saprobes are discussed.