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Eight species of the Botryosphaeriaceae (canker and dieback pathogens) were identified on native Syzygium cordatum in South Africa, based on anamorph morphology, ITS rDNA sequence data and PCR-RFLP analysis. The species identified were Neofusicoccum parvum, N. ribis, N. luteum, N. australe, N. mangiferae Botryosphaeriaceae from native hosts could pose a threat to introduced Eucalyptus spp., and vice versa.

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Mango sudden decline is a recently introduced, economically serious disease in Oman. Affected mango trees have wilting symptoms that usually begin on one side and later spread to involve the entire tree. Trees exude amber-coloured gum from the bark of their trunks or branches and vascular tissues are discoloured. Having entered Oman in the recent past, survey data is presented that shows the disease to have spread throughout the northern part of the country. Evidence is presented that the vascular wilt pathogen Ceratocystis fimbriata causes mango sudden decline disease in Oman, possibly in concert with Lasiodiplodia theobromae and the recently described Ceratocystis omanensis. Isolates of these fungi from affected trees, cause infection and can be recovered from inoculated seedlings. Bark beetles (Hypocryphalus mangiferae) are shown to carry C. fimbriata and L. theobromae and are presumably responsible for transmitting both pathogens to healthy mango trees. Acting as a wounding agent and vector, the bark beetle is likely to have assisted the rapid spread of the disease across Oman.

During 1998, a new disease appeared on trees representing a Eucalyptus grandis × E. nitens (GN) hybrid in a nursery in KwaZulu/Natal. The disease has subsequently spread to other Eucalyptus species, hybrids, and clones in nurseries and plantations throughout South Africa. Typical symptoms of the disease include dieback of young shoots and leaf blight. This ultimately leads to stunting of trees. The objective of this study was to isolate and identify the causal agent of the disease. A bacterium was consistently isolated from infected tissue. Pathogenicity tests were undertaken with a range of bacterial strains. Four pathogenic strains were selected from different geographical regions and Eucalyptus hosts for further study. The bacterium causing Eucalyptus leaf and shoot blight is gram negative and rod-shaped, varying in size from 0.5 to 0.75 μm wide and 1.0 to 2.0 μm long. Colonies of this bacterium have a yellow pigment. The results from the Biolog tests identified the bacterium as Pantoea agglomerans with a similarity index of 0.315. The 16S rDNA sequences of the purported Pantoea sp. were compared with those of other related Enterobacteriaceae from GenBank/EMBL. Phylogenetic analysis using PAUP revealed that the isolates group together with P. agglomerans, P. ananatis, and P. stewartii subsp. stewartii. The fatty acid profiles and phenotypic characteristics of the new pathogen are similar to P. ananatis, and % G + C is within the range of this species. DNA:DNA hybridization between the four strains and the type strain of P. ananatis conclusively showed that the bacterium causing blight and dieback of Eucalyptus in South Africa belongs to this species. This is the first report in which P. ananatis has been found as a causal agent of a disease on Eucalyptus.

Dothistroma needle blight (DNB) is a serious disease of pines (Pinus spp.), with a worldwide distribution. It is caused by the ascomycete fungi Dothistroma septosporum (teleomorph: Mycosphaerella pini) and Dothistroma pini (teleomorph unknown). Recently, DNB was found on Pinus peuce in Austria, Pinus pallasiana in Ukraine and the European part of south-western Russia, as well as on Pinus radiata and Pinus wallichiana in Bhutan. Based on DNA sequence comparisons of the internal transcribed spacer and b-tubulin gene regions, isolates from Austria and Bhutan were identified as D. septosporum, while isolates from Ukraine and south-western Russia were identified as D. pini. Additional isolates studied from Pinus mugo in Hungary confirmed the presence of D. septosporum in this country. The record of D. septosporum on exotic P. peuce in Austria represents a new host report of this needle blight pathogen in Europe. Likewise, DNB and the associated pathogen, D. septosporum are reported from Bhutan, eastern Himalayas, for the first time. In addition, D. pini was found in two European countries and on a new host, P. pallasiana. These European records represent the only reports of D. pini from outside the north-central USA. Morphological examination of selected specimens from different hosts and countries showed that D. septosporum and D. pini overlap in the length of their conidia, while the width is slightly wider in D. pini than in D. septosporum. The differences in conidial width are so small, however, that identification of the two Dothistroma species solely based on morphology is virtually impossible. The new host and country records provided here are consistent with the continuing trend of reports of the DNB pathogens from new hosts and new geographical areas during the last two decades, particularly in the northern hemisphere.