Morphological Characterization of Fungal Disease on Tapped Boswellia papyrifera Trees in Metema and Humera Districts, Northern Ethiopia

Boswell papyrifera is a tree species which is found in Amhara, Tigray, and Benshangul Gumuze region and used for the production of frankincense. Frequent tapping at different rounds and at different position of the tree is made to produce frankincense. A study aiming at evaluating the health status of tapped Boswellia papyrifera was carried out on samples obtained from Metema and Humera. Galls were commonly observed on most tapped Boswellia trees and a black wood discoloration was found on the wood beneath these galls. Isolation made from the discolored part of the wood resulted in growth of fungal colonies with a white to gray fluffy aerial mycelia which later changed into blackish mycelial growth as it matures. The spore of the fungus has hyaline, ellipsoid to ovoid shaped and it has one septa. The spore has a rounded base and truncate apex. The color, the shape of the colony and the characteristics of the conidia is found to be identical with description of Lasiodiplodia theobromae. Hence, based on the morphological characteristics of the colony and the spore, the fungus isolated from symptomatic trees, is tentatively identified as Lasiodiplodia theobromae. Molecular characterization is essential to confirm the identity of the fungus. The pathogenicity test resulted into development of lesion depicting that the fungi isolated from Boswellia papyrifera can cause disease on the tree.