Impact of Parvodontia austrosinensis on Lansium domesticum in Northern Thailand

Abstract

Lansium domesticum (Osbeck) Sahni and Bennet (Longkong) is a highly important and valuable fruit crop in Thailand. The mycobiota of L. domesticum has been understudied. In our survey of fungal diseases affecting fruit crops in Thailand, we observed unusual mycelial development in organically cultivated L. domesticum in Uttaradit Province. The mycelia initially appear as cords on the upper half of the young trees and spread towards the crown. However, the adverse growth of mycelial cords shows invasive development over the tree and is associated with fruits showing soft rot. The trees covered with mycelia cords eventually decay and die, and the effect was observed to be irreversible. Taxonomic and phylogenetic studies identified the mycelial cord‐forming fungal species as Parvodontia austrosinensis. Pathogenicity studies on detached leaves and fruit bunches showed field symptoms confirming P. austrosinensis as the mycelial cord‐forming fungi on L. domesticum and pathogen associated with fruit soft rot. This study presents the first geographic and host record of P. austrosinensis in Thailand on L. domesticum . Moreover, it is the first report of P. austrosinensis associated with fruit soft rot and plantation decay. Furthermore, this study is the first report on the disease potential of Cystostereaceae, which was previously known for a saprobic lifestyle.

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