Oral Presentation Science Protecting Plant Health 2017

Copper tolerance in Pseudomonas syringae pv. tomato from tomatoes in Queensland, Australia (3919)

Karina Griffin 1 , Cherie Gambley , Philip Brown 1
  1. Central Queensland University, Bundaberg, QLD, Australia

Bacterial speck (caused by Pseudomonas syringae pv. tomato) and bacterial spot (caused by Xanthomonas spp.) can cause significant crop damage and loss in tomato and pepper. There are limited pesticide control options available for these diseases, with copper based bactericides currently the basis of bacterial crop management programs in Australia. Copper bactericides are used frequently over the entire crop cycle and are also used on many other horticultural crops. Copper tolerant isolates of bacterial speck and spot have been identified worldwide. In Queensland, both bacterial speck and spot occur on tomato and bacterial spot on pepper. There are three reports of copper tolerance in bacterial spot and speck in Australia, with tolerance identified in bacterial spot isolates from pepper in Queensland and in bacterial speck isolates from tomatoes in New South Wales and Victoria. Queensland produces approximately 60% of Australia’s fresh market tomatoes with climatic conditions facilitating year round production in some areas. These producers are increasingly reporting a reduction in the efficacy of copper based sprays for bacterial disease control in tomatoes. Despite this there have been no studies undertaken to determine if copper tolerant P. syringae pv. tomato are present on tomatoes in Queensland. In this study copper tolerance screening methodology for P. syringae pv. tomato were analysed and tested, isolates from tomato producing regions in Queensland and some other Australian states were screened for tolerance, multiplex diagnostic testing for tolerance was explored and genome sequence analysis of Australian P. syringae pv. tomato. The findings of this study have important implications for Queensland tomato producers and highlights the need to adapt bacterial disease management strategies to control copper resistance development.