What was it all about? 

This project had a focus on biosecurity strategies around the Fusarium wilt Tropical Race 4 (TR4) fungus – one of the most destructive diseases of banana. The work delivered new science, information and practices to help in avoiding, containing, and managing TR4.

Project activities were geared towards helping the industry successfully contain the disease and prevent further spread of the fungus through the adoption of robust, science-based biosecurity practices; and facilitating the development of economically viable production systems capable of minimising inoculum build-up, suitable for use on infected or at-risk farms.

The project team report that adoption of effective biosecurity practices on north Queensland banana farms has been significantly supported by project activities, which included – but weren’t limited to – identifying and communicating…

• How to monitor for the disease.

• Risk pathways for spread of the pathogen, and associated biosecurity practices. The fungus that causes TR4 cannot move itself, rather it must be moved for the disease to spread. It can be spread by the movement of contaminated water (spores in irrigation, drainage and flood water), infected plant material and infested soil (a teaspoon of infested soil is enough to start a new infection). The project examined the aspects of the banana production system that related to these movement risks to determine what farm practices presented the greatest risk of spreading the disease. Once these were identified, then effective and practical methods to manage them were developed in conjunction with banana growers. The assessment also helped to identify knowledge gaps that required more R&D effort.

• The most effective disinfectant products, and how to manage their use, with this information collated into project fact sheets on sanitisers (see the ‘act now’ section below).

• How to effectively destroy inoculum in infected plants to minimise build up in the soil. Each infected banana plant is effectively a ticking disease ‘time bomb’. As the disease kills the plant the fungus within produces millions and millions of very robust, long-lived survival spores that can persist in the soil for decades. If the plant is allowed to die and fall over on the ground, then those spores return to the soil where they can be picked up and moved elsewhere by machinery, shoes, wild and feral animals, and washed downhill by surface run-off where the same vectors can pick it up and move it, or it ends up in a river, creek or dam where it can be distributed by irrigation onto a new farm. Hence, being able to kill all the disease in an infected plant is crucial to stopping further spread – even when it means killing the plant and locking up that area so that no crop is grown there again, and no-one can re-enter the locality.

The project has shown that the use of very high, toxic rates of urea fertiliser (much higher than the normal fertiliser rates used) to produce ammonia gas in very localised plots and in specific ways (bagging infected banana stem and adding urea, spreading it on the ground adjacent to the plant and sheeting the site with plastic) can dramatically reduce the amount of inoculum that persists. This means that the risk of accidental movement of infected plant or soil from the site is very much reduced and is key part of containing the spread of the disease.

The project has also significantly progressed development of methods for assessing plant stress and its influence on Fusarium infection, identified possible rotation crops that suppress fungus populations in the soil, and looked at the influence of ground cover and nitrogen management practices on the soil microbiome and its capacity to suppress Fusarium.

The project’s work has been world-leading in many areas, with the project team linking in with the international R&D community as a part of its work. This disease is spreading rapidly internationally, and the team reports that researchers and growers from Central America, Israel, South Africa and other areas have been visiting to learn about the work, especially the biosecurity practices work.

ACT NOW  

• Download the Banana best management practices on-farm biosecurity manual, produced by the project and released in May 2017. It includes a self-assessment checklist on biosecurity practices, a management plan template, and information to implement improved practices, including those related to zoning, general farm operations, crop production and fruit movement.

• Access info on effective disinfectant products and their use, produced off the back of the project’s sanitiser trials.

• Check out these other fact sheets from the project, produced between 2015 and 2018 as part of the ‘Panama Disease Tropical Race 4 Research Update’ series…
  
  
• Quaternary ammonium products aid in the management of Foc
  
  
• Testing the efficacy of urea as a treatment for the destruction of Foc in infected soil
  
  
• Proximal sensing tools for early, quantifiable stress and disease detection
  
  
• Quaternary ammonium (QA) products: How can you monitor them? How long are they effective for and are they corrosive?
  
  
• Soil management, organic matter, biological activity and disease suppression
  
  
• Multi-scale monitoring tools for managing Australian tree crops