Dropped nuts are of various sizes, but more often are large, nearly mature nuts with irregular brown to black areas beginning at the stem end of tree nut. No threats Asian proved as deadly palm palms as the South American palm disease and Fusarium fungus.
Diseases and Disorders of Ornamental Palms
First, to draw attention to the major sources of technical information on rattans and their products.
There is no known prevention for this lethal disease and once in a palm it is untreatable.
However, once placed into our native soils they may become deficient. Ants will sometimes farm mealybugs for honeydew.
Moth wipes out French Riviera's palm trees - Telegraph
Sarawak endemic Calamus senalingensis?
What to Do if a Chinese Fan Palm Leaves Turn Brown?
Proceedings Ist regional rattan meeting The common practice of severely pruning palm trees to lengthen the time between trimmings exposes the plant to pathogens.