Bacterial diseases on eucalypts. Current knowledge

Abstract

In recent years there has been a substantial increase in health problems on Eucalyptus spp. plantations elsewhere. Several diseases are currently affecting this crop, predominantly those caused by fungi. However, bacterial diseases have globally increased in importance. Eucalyptus plant pathogenic bacteria can cause: i) leaf spots, ii) shoot blight and iii) vascular wilt. Bacterial leaf spots have been associated with genera Xanthomonas, Pseudomonas, Erwinia, Pantoea and Rhizobiaceae, being Xanthomonas axonopodis the predominant species. Bacterial die-back of bacterial shoot blight can be caused by several species, namely Erwinia psidii, Pantoea ananatis, Enterobacter cowanii, Xanthomonas campestris and X. vasicola, whereas vascular wilt has been associated with Ralstonia solanacearum and Erwinia psidii. These diseases represent a potential risk for forestry production, as reported in different climatic zones worldwide causing serious economic loss, in both nursery and field, affecting a wide host range in the genus Eucalyptus, and some species of Psidium. In addition, the effective dissemination of these bacterial diseases makes controlling them difficult, thus the deployment of genetic resistance germplasm is strongly recommended to minimize the impact of these diseases.