Poster Presentation Science Protecting Plant Health 2017

Testing the efficacy of urea as a treatment for the destruction of Fusarium oxysporum f. sp. cubense in infected soil. (#349)

David J East 1 , Tony B Pattison 1
  1. Queensland Department of Agriculture and Fisheries, South Johnstone, QUEENSLAND, Australia

The confirmation of Fusarium Wilt Tropical Race 4 (TR4) (Fusarium oxysporum f.sp. cubense Race 4) (Foc) near Tully has put at risk the $600 million per year Australian banana industry. To reduce the threat to the wider banana growing industry, effective destruction protocols of infected sites are imperative, to minimise inoculum and limit pathogen spread. Biosecurity protocols treat infected sites, plants and soil, with a high doses of urea to destroy all inoculum present. The efficacy of urea treatment has been tested by using banana field soil contained in sterile jars, and inoculated with Foc Race 1 (VCG 0124) (FocR1) at a rate of eighty conidia per gram of soil, and incubated for seven days. A urea treatment equivalent to 500 g urea m-2 was then applied in triplicate, along with controls and incubated for twenty eight days. Pieces of banana pseudostem from a FocR1 susceptible variety were surface sterilised, placed in contact with the soil in the jars, and incubated for a further seven days. The pseudostem was then removed, surface sterilised, and twenty one pieces from each jar were placed onto Fusarium spp. selective medium. The plates were then assessed after five days for the presence or absence of the pathogen. FocR1 was not recovered from any of the urea treatments, but was consistently recovered from the controls. The experiment has been repeated twice, progressively reducing the rates urea. No FocR1 has been recovered from any urea treatment down to a rate of 62.5 g urea m-2. However, a 6 % recovery rate of FocR1 was recorded when urea was applied at 31.25g urea m-2. Further refinement of the procedure is currently underway to determine the point where urea loses its effectiveness as well as to understand which urea hydrolysis by-products have the greatest efficacy.