PISTACHIO BACTERIAL DIEBACK IN AUSTRALIA - CHARACTERISTICS AND PATHWAYS OF THE INFECTION

E. Facelli, E. Scott, C. Taylor, N. Nancarrow, R. Emmett, M. Escoto-Rodriguez, M. Sedgley
Symptoms of pistachio bacterial dieback include decline, dieback, internal staining, trunk and limb lesions and, in some instances, tree death. The causal agent is Xanthomonas translucens. The main mode of transmission of the bacteria from tree to tree is through pruning tools. We report here results from experiments aimed to elucidate aspects of the disease cycle. To study the colonisation of woody tissue we inoculated young potted trees and assessed the presence of the bacteria at intervals from the inoculation point over time, and recorded when the vascular tissue became discolored (internal staining). To test the effect of the infection on water uptake we measured the water conductivity of infected and non-infected potted and field trees. Based on the results from these experiments we hypothesised that the infection is localised to the vascular tissue active in the year of infection and that, in consequence, very diseased trees must have had several infection events. Accordingly, we established one field and one glasshouse experiment in which trees are being inoculated repeatedly, and a second field experiment in which trees were pruned severely using disinfested pruning tools and the wounds simultaneously drenched with a bactericide. Results to date are reported.
Facelli, E., Scott, E., Taylor, C., Nancarrow, N., Emmett, R., Escoto-Rodriguez, M. and Sedgley, M. (2006). PISTACHIO BACTERIAL DIEBACK IN AUSTRALIA - CHARACTERISTICS AND PATHWAYS OF THE INFECTION. Acta Hortic. 726, 613-614
DOI: 10.17660/ActaHortic.2006.726.104
https://doi.org/10.17660/ActaHortic.2006.726.104
Xanthomonas translucens, rate of spread, water conductivity, multiple infections, drastic pruning.
English

Acta Horticulturae