A diverse assemblage of Botryosphaeriaceae infect Eucalyptus in native and non-native environments

Abstract

The Botryosphaeriaceae cause endophytic infections of leaves and bark of various trees, including Eucalyptus, and they apparently persist in this state for extended periods of time. Under conditions of stress, these fungi cause many different disease symptoms on Eucalyptus, of which stem and branch cankers and die-back are the most prominent. Given their cryptic, endophytic nature, the Botryosphaeriaceae are easily overlooked when moving seeds and plants around the world. It is, therefore, not surprising to see a growing number of examples of introductions of Botryosphaeriaceae into new environments. In the past, three species were commonly reported from Eucalyptus, namely Botryosphaeria dothidea, Neofusicoccum ribis (reported as B. ribis) and Lasiodiplodia theobromae. It is now known that B.  dothidea and N. ribis are generally rare on Eucalyptus, and that Aplosporella yalgorensis, B. mamane, N. parvum, N. eucalyptorum, N. eucalypticola, N. australe, N. macroclavatum, N. andinum, N. mangiferum, Dichomera eucalypti, Dichomera versiformis, Fusicoccum ramosum,  Pseudofusicoccum stromaticum, P. adansoniae, P. ardesiarum, P. kimberleyense, Lasiodiplodia crassispora, L. gonubiensis, L. pseudotheobromae and L. rubropurpurea also infect this host. Interestingly, different species dominate on Eucalyptus in different regions of the world, irrespective of whether other species occur in that environment or not. As examples, in parts of eastern Australia, N. eucalyptorum and N. eucalypticola dominate, although N. australe is common on Acacia spp. in this area, while in Western Australia N. australe dominates. In South Africa and Chile N. parvum, N  eucalyptorum and N. eucalypticola are common, despite the presence of N. ribis and N. australe on related hosts such as Syzygium. In Venezuela, there are five other species not common on Eucalyptus elsewhere, but L. theobromae dominates. In Colombia, B. dothidea and N. ribis, and in  Uganda and Ethiopia, L. theobromae and N. parvum, are most common. These fascinating patterns of distribution are explored, while their pathogenicity and potential influence on Eucalyptus plantations and surrounding native plant communities are considered.

Southern Forests 2009, 71(2): 101–110