Hi all,

I've got some Chungii Bamboo which was doing great for a while but has recently developed a problem. New shoots generally get to around 12" to 18" or so then turn brown and die. Any suggestions greatly appreciated.

How many? Is there more healthy shoots than those that failed? Usually bamboos start growing more shoots than they can support as a backup in case some get damaged by pests.
As the majority of shoots grow, some will start declining and by the time most of the shoots start leafing out, 'backup' shoots rot and die off. Perfectly normal if there's not too many.

_________________
http://cold-hardy.com

If I had to guess, I would say that your plant is just shutting down as your days are getting shorter and cooler. If it already produced shoots that elongated normally over the summer and fall, and these are just late season shoots, I would not worry, as the plant should resume growth when the weather gets warmer and the days lengthen.