April 2014. I message broadcast on Radio New Zealand was put out on Pestnet, and received a number of responses from members. The message was a warning from the FAO that countries needed to tackle the problem of Fusarium wilt tr4 or else the world’s bananas would ‘face massive destruction”.
The question was asked whether Fusarium wilt is in the Pacific yet. In reply a copy of an SPC fact sheet on the disease in the Pacific was provided. In addition, a member who had done surveys for the disease in the Pacific had this to say:
As far as I am aware, there have been no other confirmed identifications of any strains of Fusarium oxysporumf.sp. cubense (Foc) on any new islands in the Pacific, since the situation summarised in the SPC pest advisory leaflet in 2005.
I had a look at the Plantwise map just now and it gives us three of the published records: two from PNG in the 1990s, one for Tonga about ten years ago and one for Fiji from the 1930s.
I know from conversations I have had that there is still a fair bit of confusion about this topic, definitely amongst the non-pathologists, but also amongst pathologists who are not familiar with this disease too.
The really important thing that cannot be over-emphasised for the Pacific islands is that the original message was about ‘tropical’ race 4 of Foc.
‘Tropical’ race 4 of Focis notin the Pacific.
This is the banana grower’s worst nightmare because it kills just about ALL banana plant genotypes. The other strains only kill a few banana types and the rest are resistant. The disease is so devastating because the resting spores of all strains of the fungus last several decades. The only way out is to not plant susceptible bananas there again and, of course, Foc‘tropical’ race 4 does not leave you much choice.
That is why biosecurity awareness is so important for the Pacific islands, and the same goes for anywhere else that does not yet have Foctr4.
Further comments on the old record from Fiji.
The aim was to collect samples and check the previous idnetifications, but true symptoms of the disease were not found. In the original paper (Parham 1935), it details what appears to be Fusarium cubense(synonym of Foc) isolated from wilting banana plants on Kadavu and Viti Levu. After a large commercial plantation was destroyed as a containment response, no further reports are known in Fiji, presumably because banana plants susceptible to this strain of the fungus were not grown again in the infested sites. The paper does not state what type of banana plants were destroyed, but the industry was based at that time on Gros Michel. Focthat destroyed the world’s banana industry in middle of last century – and gave us Cavendish bananas as a result.
Gros Michel is called Jaina balavu in Fiji (because it is very tall), and there are still a few around, so it would pay to check them for wilt symptoms.
Parham BEV (1935) Annual report of banana disease investigations for the year 1934. Annual Bulletin Divisional Report for 1934. Department of Agriculture, Fiji. p41-48.
One of the best accounts of the disease and it symptoms is Moore NY, Bentley S, Pegg KG, Jones DR (1995) Fusarium wilt of banana. Musa disease fact sheet No. 5. INIBAP, Montpellier, France, 4 p. See: http://www.bioversityinternational.org/uploads/tx_news/Fusarium_wilt_of_banana_702.pdf. This article is especially good as it has instructions on how to sample plants if they are suspected to have the disease.
See also the challenge in Australia: http://www.freshplaza.com/article/124722/Australian-banana-industry-balances-biosecurity-risks-against-star-market-performer.