|Foliar decay on Malayan dwarf seeding.|
|Hibiscus tiliaceous, by By Vincenzo Defifoot|
(Own work, ccby-sa 3.0)
- In Vanuatu there is an endemic virus that does not cause any symptoms of pathology in the indigenous tall population, yet exotic germplasm is destroyed by it.
- In Solomon Islands in 1963 I planted imported seed from Rangiroa atoll but the seedlings died due to severe leaf spot (Drechslera sp) damage yet the local tall was not affected.
- The leaf beetle Brontispa longissimia causes very little damage to the local tall in Solomon Islands yet when it reached Vietnam recently mature palms were destroyed by it.
- The hybrid Malayan orange dwarf by Rennell Tall has given a 30% increase in yield of copra in plantations in Solomons yet in New Britain (PNG) it was severely attacked by Scapanes australis – a local rhinoceros beetle.
- PB121 which yielded very well in Cote d’Ivoire was attacked by Phytophthera sp in Indonesia and I understand that many died.
- The Rennell island Tall was widely used with great success in the Pacific region; of course in some places, there is the scapanes problem, but in many other, it was OK: Papua New Guinea mainland, Fiji, Samoa, etc….
- The Sri Lanka Green dwarf and the Vanuatu Tall are the only varieties tolerant to LYD disease in Ghana – and there is no LYD in Sri Lanka and Vanuatu
- The PB121 hybrids was mainly a success, even if some problems were encountered in some places of Indonesia - the real problem was not phytophthora except in a few zones, but the small size of the fruit was not appreciated by the farmers – Many of them were very happy to turn their PB121 to heavy Toddy production.
- The case of Vanuatu Tall and the DFMT disease is very strange, and definitely we did not conduct enough research of this question. The Malayan Red Dwarf is the variety most sensitive to the DFMT disease. But MRD can be “vaccinated” in the nursery, and then it does not die anymore from the disease. Nobody tried to take seednuts from these “vaccinated” MRD, plant them and see if the progeny is sensitive of not to the DFMT disease; may be the DNA of the virus integrate the genome of the coconut palm, or something like that. May be the Vanuatu tall is not at all resistant to the DFMT, but is simply “vaccinated”. May be this kind of “Vaccination” help the Vanuatu tall to tolerate the Lyd disease in Ghana….
Mike Foale to John Randles and us, 20th October 2016
- The Vanuatu Tall is not at all tolerant to FDV, he is only "vaccinated", and this vaccination can be transmitted by seeds
- As Vanuatu Tall is also tolerant to Lethal Yellowing Disease (LYD) in Ghana, this vaccination against FDV is also efficient for LYD
- If the Vanuatu Tall is not vaccinated but really tolerant to FDV, there is a unique physiological and genetic reason why Vanuatu tall is tolerant to Both LYD and FDV
Pacific Pests and Pathogens - Fact Sheets - Coconut foliar decay (231)