Pantoea ananatis has been reported as the causal agent of bacterial blight and dieback of Eucalyptus seedlings in South Africa. Young leaves present symptoms first, with leaf spots that become water-soaked and eventually form larger necrotic lesions. Trees either fail to survive or become multi-stemmed (Coutinho et al., 2002). In the last decade, similar symptoms have been observed in nurseries and plantations in Uganda, Argentina and Uruguay. The bacteria isolated from these diseased trees were identified as belonging to three novel species of the genus Pantoea: P. vagans, P. eucalypti and P. deleyi (Brady et al., 2009). It has been suggested that a complex of Pantoea species may be responsible for bacterial blight and dieback in Africa and South America (Coutinho et al., 2011). P. ananatis, P. vagans, P. eucalypti and P. deleyi, have been isolated from a wide range of Eucalyptus species, hybrids and clones which is of concern for the forestry industry.As part of an on-going isolation campaign in countries of Africa, South America and Asia, Eucalyptus seedlings are regularly examined for symptoms of bacterial blight and dieback. Bacterial isolates obtained from the diseased material are identified using a polyphasic approach based on Gram staining, oxidation-fermentation testing, partial 16S rRNA gene-and gyrB-sequencing. P. ananatis and P. eucalypti are regularly isolated in South Africa, while P. vagans and P. dispersa are more commonly isolated in Colombia and Thailand, respectively (Swart, 2009). In 2006/2007, bacteria were isolated from diseased Eucalyptus material in Colombia, Rwanda and South Africa which could not be assigned to any of the recognized species of the genus Pantoea. Sequencing of the gyrB gene placed these isolates in the genus Pantoea, and indicated that they constituted three novel species (Swart, 2009). In the present study, these isolates were further examined using a polyphasic approach to confirm that they constitute three novel species of the genus Pantoea.Bacteria were isolated from diseased Eucalyptus material as previously described (Brady et al., 2009). Reference strains were obtained from the BCCM/LMG Bacteria Collection (http://bccm.belspo.be) and recovered on tryptic soy agar according to the provider's instructions. A list of strains Abbreviation: MLSA, multilocus sequence analysis.The GenBank/EMBL/DDBJ accession numbers for the 16S rRNA, atpD, gyrB, infB and rpoB gene sequences

A number of bacterial pathogens have previously been shown to cause blight and die-back of Eucalyptus species. These include Pantoea ananatis, Pseudomonas cichorii, Xanthomonas axonopodis and Xanthomonas dyei pv. eucalypti. In 2003 a newly established compartment of a Eucalyptus grandis clone in the Mtunzini area of South Africa showed extensive leaf blight and die-back. The plantation was located in an area where sugarcane is extensively cultivated. Bacteria were commonly found exuding from leaves and petioles. Numerous insects in the family Miridae were observed in the plantation and collected. Isolations from diseased material and mirid insects yielded two distinct bacterial species. The objectives of this study were to identify these bacterial species and determine their aetiology. Phenotypic methods as well as 16S rRNA and gyrB sequencing were performed on all isolates, confirming the presence of P. ananatis and Xanthomonas vasicola, of which the pathovar vasculorum (Xvv) is known to infect sugarcane and maize. Xanthomonas vasicola isolates from E. grandis and a strain of Xvv, previously isolated from sugarcane, were inoculated into the susceptible Eucalyptus clone and three sugarcane cultivars. All isolates were found to be pathogenic. This study thus suggests that X. vasicola has made a significant host jump from sugarcane to eucalypts in South Africa.