Poster Presentation Science Protecting Plant Health 2017

Using Trichoderma to suppress Fusarium Wilt (Fusarium oxysporum f.sp. cubense) in banana cropping systems (#350)

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) (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, the development of management techniques to reduce inoculum and limit disease movement is imperative. Twenty Trichoderma isolates were collected from banana growing soils which had a history of Foc race 1 (FocR1). The isolates were screened for potential to reduce growth of the pathogen. A Trichoderma virens isolate (BRIP65209) consistently suppressed the growth of FocR1. The T. virens isolate demonstrated the highest inhibition of the pathogen, rapid growth and completely overgrew the pathogen. The efficacy of the T. virens isolate to suppress FocR1 was confirmed by inoculating lengths of banana pseudostem with FocR1, the T. virens isolate or both and compared to uninoculated pseudostem.  The pseudostems were maintained in sterile sealed containers for three months, before being removed, homogenised, and strained through cheesecloth. The total number of conidia and chlamydospores of Foc was then determined.  The addition of the T. virens isolate to the pseudostem reduced the number of Foc conidia. Furthermore, when the T. virens isolate was added to the pseudostem with FocR1, chlamydospore production was reduced by two thirds relative to FocR1 only inoculation. A novel application method for the application T. virens was then tested, where the T. virens was injected directly into the pseudostem of recently harvested banana pants. The following suckers of the treated plants showed no reduction in growth measurements. In addition, the treated pseudostems exhibited rapid decomposition, which may limit Foc proliferation within decaying banana pseudostems. Further efficacy testing of the T. virens isolate is required in the field to confirm suppression of Foc, but the technique provides promise to limit losses to Fusarium wilt.