Morphological and Molecular Characteristics of the Oak Tree Canker Pathogen, Annulohypoxylon truncatum

Abstract

Cankers are localized dead areas in the bark of stems, branches or twigs of many types of trees and shrubs, and are usually caused by fungi. We observed severe canker symptoms in oak trees located in Gyeongnam province in 2011. A total 31 trees were discovered with cankers of varied size, with an average of 48.5 × 15.2 cm. Black, half-rounded globular mound shaped stromata were associated with the cankers, and the asci of the fungi associated with the cankers were cylindrical shaped with their spore-bearing parts being up to 84 µm in length. The average fungal ascospores size was 7.59 × 4.23 µm. The internal transcribed spacer sequence for the canker causing fungus showed 99% similarity to the sequence of Annulohypoxylon truncatum. In this study, the isolated fungus was precisely described and then compared with fungi of similar taxa.

Oak Tree Canker Disease Supports Arthropod Diversity in a Natural Ecosystem

“…The morphological characteristic of the fungi were compared to previously identified Hypoxylon images ( Fig. 1B ) ( Ju and Rogers, 1996 ; Cha et al, 2012 ).…”

Commodity risk assessment of maple veneer sheets from Canada

“…Despite its wide distribution, very poor information is available on biology and damage of A. truncatum . Severe cankers have been observed in Korea on Quercus acutissima and Q. variabilis , causing dark brown discoloration of the sap in affected trees; dark brown glomerate stromata with spherical perithecia are associated with the cankers (Cha et al., 2012 ). In North America, the fungus was only found on dead branches of Quercus spp.…”