July 2007. Kiribati asked for assistance concerning a problem of breadfruit: was it cause by disease or environmental effects? The problem occurs especially on seeded breadfruit and rarely on seedless varieties. Locally, it is thought to be the ‘bleeding/red disease” with an unidentified cause. Kiribati wanted to know how to sample, isolate and identify the cause as well as how it might be controlled. The condition is a worry as it seems to be spreading and quite serious in some islands.
A response was made by a scientist, previously with the Secretariat of the Pacific Community, who had worked on breadfruit disease in Kiribati, especially that of the fruit, caused by Colletotrichum gloeosporioides.
What was discovered previously:
1. Many breadfruit trees on Kiribati are past their prime and are becoming much more susceptible to disease as they get older. Old people we interviewed in the 11 villages on Butaritari indicated that using traditional husbandry systems of breadfruit management, a root sucker from aging trees would normally be allowed to grow up to replace the aging tree. The old people were quite scathing toward the young people and their lack of enthusiasm for managing the trees properly.
2. Whilst breadfruit trees can be quite tolerant to salinity, on top of them aging, salt water incursions further weaken the trees increasing their susceptibility to disease.
3. At least three fungi known to cause canker in other fruit trees, Lasiodiplodia theobromae, Botryosphaeria spp. and Dothiorella sp., were isolated.
4. Phytophthora has also been recorded as a problem for breadfruit (causing trunk cankers and root rot) in the northern Pacific, although it was not found in Kiribati in recent surveys.
5. The idea of using chemicals on the atoll was not favoured by anyone, although the possibility exists to do tree injection if Phytophthora was the causal organism, but this is very expensive and Phytophthora was not found in surveys (that does not mean to say it is not the cause of the condition in the photo above), so it was not pursued as an option.
6. After much consultation with experts, it was thought that good husbandry and replacement of senile trees with young trees (which would have more vigour) was probably the best option. That was the idea that led to the Te Bwata Ni Mai group on Butaritari. A nursery was to be established to supply enough seedlings for a replanting scheme to replace the aging population of trees.
Reports on the study are available from SPC.