September 2004. Yellowing and eventual necrosis of coconut leaves in St Lucia. What could be the cause?

There were suggestions of nutrition deficiency and disease.

Magnesium deficiency is a possibility, but it is difficult to confirm without looking closely at the individual leaflets. Although nutrient deficiency was thought to be the cause, there was also a suggestion that a lack of potash may be the cause. What kind of coconuts are they: are they dwarf or tall? Have they ever received fertilizer?

There is another much more serious yellowing that should be watched for – coconut lethal yellowing. There is no record of it in St Lucia. But seednuts from the Malayan Dwarf in St Lucia were shipped in large quantities to Jamaica in the 1950s and 60s and formed the basis of the LY replanting programme, and were the parent for the resistant F1 hybrid Maypan. If more information is required about LY, check the Centre for Information on Coconut Lethal Yellowing (CICLY) at http://www.cicy.mx/dir_acad/cicly/main.html.