Banana Plant Protection Program
Horticulture Innovation Australia (Hort Innovation) has funded prior research into Panama disease and is currently funding the Banana Plant Protection Program, a $6.4 million dollar investment involving the University of Queensland, the Department of Agriculture and Fisheries Qld, NSW Department of Primary Industries, the Northern Territory Department of Primary Industries and Fisheries and with private consultants. This program consists of three major sub-programs, all of which are involved in Panama disease research. Sub-program 1 is focused on identification of banana cultivars that may demonstrate resistance or tolerance to pests and disease, including Fusarium oxysporum f. sp cubense Tropical Race 4. Sub-program 2 has been involved in development of cutting-edge molecular diagnostics for swift and accurate detection of the pathogen in infected material and Sub-program 3 has been investigating methods to assist in minimising the impact of the disease in the field through soil amendments, along with looking at the biology of the pathogen and specific resistance mechanisms.
The Banana Plant Protection Program also collaborates extensively with international experts in the areas of breeding, diagnostics and integrated pest and disease management. In addition to this program, HIA also funds programs with the Australian Banana Growers Council and DAFF Qld, that are involved in extending and communicating information to Australian banana growers so that they are aware of the work that their levies are funding and are assisted in utilising the outcomes of this research on farm.
Through Hort Innovation transformational fund, a strategic R&D project was initiated in 2013 with QUT. One of the objectives under this project was to find a potential solution to control TR4 in banana should incursion of disease is observed in Northern Qld. We are attempting to develop plants for Fusarium wilt Tropical Race 4 resistance and BBTV.
With the availability of banana genome sequence (2012), there is a high likelihood of identifying new R genes for TR4 that could be used in this program.
Panama disease summary
Panama disease, or Fusarium wilt of bananas is caused by the soilborne fungus Fusarium oxysporum f. sp (forma specialis) cubense. It is considered to be the most devastating disease of bananas worldwide and rose to importance late in the 19th century when it impacted on the commercial production of the bananas in the Latin America-Caribbean region. This is where the name Panama disease came from. At the time a cultivar Gros Michel was dominant and the impacts of Panama disease saw the rise of the Cavendish variety which was resistant to the race of Fusarium that had impacted the production of Gros Michel. A combination of a different variety and use of “virgin land” free from Fusarium oxysporum f. sp cubense to produce bananas saved the industry from complete collapse.
It is thought that Fusarium oxysporum f. sp cubense co-evolved with wild and cultivated bananas in South East Asia as this is where the most diversity in the pathogen occurs.
There are four races of Fusarium oxysporum f. sp cubense. In Australia the two important races are Race 1 (which infects Ladyfinger, sugar and Ducasse cultivars, but not Cavendish) and Race 4 which infects most Cavendish varieties. Race 4 has two important strains though, the Subtropical Race 4 and this usually produces symptoms following a period of cold stress and the more serious threat Tropical Race 4.
Symptoms of Panama disease can be mistaken for other problems such as water stress and other diseases. Initial symptoms may appear as yellowing of the margins of older leaves, which will darken and dry out. The leaves will collapse along the leaf stalk or at the stalk-stem junction. This leads to a skirt of dead leaves around the lower section of the banana plant. Wilting will usually occur and the stem may split resulting in plant death, however suckers may not die.
The characteristic internal symptom of Panama disease is discolouration of the tissues in the corm and pseudostem. This can be visualised by cutting the pseudostem near ground level. Reddish-brown or black lines will be visible running up and down the pseudostem.
Fusarium oxysporum f. sp cubense Races 1,2 and subtropical race 4 are present in Queensland already, with subtropical race 4 being present in South East Queensland. Tropical Race 4 is also present in the Northern Territory, but this along with the recent incursion of Banana Freckle disease in the Northern Territory has had a devastating effect on banana production in this state.
The banana industry in Australia has an estimated farm gate gross value of $550-580 million per year and approximately 90 per cent of banana production is in North Queensland. If Fusarium oxysporum f. sp cubense Tropical Race 4 were confirmed in the Tully region in QLD, this could have a devastating effect on the banana industry if it could not be contained. Unfortunately control of the disease is best achieved through prevention; utilising good farm hygiene practices and planting clean planting material. Plant Health Australia have developed an Industry Biosecurity Plan and Farm Biosecurity Manual which is a very useful resource for growers. There are no real silver bullets for controlling this disease, but our best chances of success lie with genetics.