First report of Lasiodiplodia theobromae causing canker on tapped Boswellia papyrifera trees in Ethiopia.
B. papyrifera is widely used for frankincense (incense) production. Incense is extracted by frequent, intensive and repeated wounding made at different directions and positions on the bole of the tree. Depending on the size of the tree, there could be between 6 and 16 tapping spots that are refreshed and widened 8-12 times each year at an interval of 15 to 20 days. Tapping for incense has a negative impact on the survival rate, growth and reproduction of the tree and wounding predisposes trees to microbial infection. Disease symptoms and death of B. papyrifera trees have been commonly observed in all areas where tapping has been practiced. Specific symptoms include canker formation, exudation of gum, wilting, dieback, vascular browning and death of the tree. A study was carried out to determine the cause of the observed disease on tapped B. papyrifera trees. Samples were collected from Humera and Metema Districts, North Ethiopia. Isolation was made from ten tapped trees that developed scars and galls on the stem. Based on cultural and morphological characteristics, and pathogenicity test, the causal agent of the disease was identified as L. theobromae. This fungus has previously been reported to cause dieback and death of mango and cacao trees in Pakistan and Cameroon, respectively. This is thought to be the first report of L. theobromae infecting B. papyrifera in Ethiopa, which represents a new constraint to the sustainable management of B. papyrifera and incense production.