March 2016. A few 3-year-old coconuts are showing symptoms on the leaves as in the photographs. Using the LUCID app-PALM SYMPTOMS it was thought to be a blight. Can anyone help in the diagnosis.

Two suggestions were given: (i) blight but for curiosity just have a close look whether any insect (e,g., black headed caterpillars) are present. Are there any symptoms of scrapping of green parts of leaf, and (ii) could it be potassium deficiency.