Phytoplasm, Crown dieback Minimize

October 2003. A betel nut, Areca catechu, bud rot was reported from Guam, and members were asked if they had seen anything like it before.

Phytophthora bud rot was thought to be a likely candidate, but then members were reminded of a similar disease, a crown dieback, caused by a phytoplasma, occurred in Saipan in 1996-97. Symptoms were very similar to those being reported by Guam. The disease spreads from the crown throughout the trunk. Specimens were sent to the University of Florida for scanning by electron microscopy. The affected trees also had a Pseudomonas infection, and were heavily infested with spiraling whitefly at the time.

Many trees were killed by the disease. Unfortunately, most were mature and bearing. Growers have since replanted with new material, and these have survived, although the nuts are smaller than those produced previously. The disease is seen only sporadically now, but is still there, and will probably reappear when vectors and climate are right for it.

Mention was also made of the condition in Reef Islands, Solomon Islands. Here flower buds decay, but there was no obvious rot of the spear leaf (i.e. bud rot), but there were long, thin, red lines of rot on the trunk, without stem bleeding. Viroids were found, but cause and effect was never substantiated.