Etiology of Mango Tree Mortality in Pakistan

Abstract

ABSTRACT The present research investigated the etiology of mango tree mortality in Pakistan. The survey of mango orchards conducted during 2004–05 and 2005–06 revealed a severe infestation of the bark beetle. These beetles were collected for their identification and isolation of fungi associated with them. The beetle was identified as ambrosia bark beetle, Hypocryphalus mangiferae (Stebb.). The results of identification of fungi associated with the bark beetle revealed four species of fungi. These fungi were isolated and identified as Ceratocystis fimbriata Ellis & Halst., Fusarium solani (Mart.) Sacc., Botryodiplodia theobromae Pat., and Aspergillus niger Tiegh. Among all the fungi, C. fimbriata was the most predominant fungus with maximum frequency of 40.7%, followed by F. solani 25.4%, B. theobromae 19.3%, and A. niger 14.6%. A pathogenicity test of the predominant fungi in barks of mango trees revealed that the maximum infection rate was caused by C. fimbriata alone (77.1 ± 5.1%) followed by C. fimbriata + F. solani (46.6 ± 3.9%), F. solani alone (7.8 ± 1.6%), and mango bark beetle–released trees (0.3 ± 0.3%). The disease only developed in trees where culture disks were inserted.