I have found several shoots around my Pseudosasa japonica 'tsutsumiana' dissappear over night. After that I found a maze of tunnels below the whole clump and started using trap to finally get the intruder. After a couple of days and several older culms and new shoots later, I did catch something, a mole. I thought that vole that did that damage dissappeaed because it seemed the damage stopped. After another couple of days, old culms started to die off in large numbers. Whole stems were taken into the ground, new shoots, gone, rhizomes gone, roots nibbled... By now half of the 2 year old clump is practically gone! I checked 5 places below the clump and I found enormous underground hallway just below the plant. all roots and rhizomes that went below it are gone. When making mentioned 5 small holes, I ended up with 6 tiny divisions of freshly nibbled rhizome parts and culms. Some have roots, hopefully they make it and with a lot of luck rhizome will also start growing from at least one of buds that could emerge on lower parts of the culm.
I'm not sure what to do now. It looks like this plant got hit really hard. It started shooting like crazy, but it lost nearly everything new and most of the old growth. I also find almost 3m long rhizome (the plant is small and I have no idea how it could run that far away - perhaps it knew about voles in the neighborhood

) into not desired direction over the pathway and that runner made it with a shoot. Perhaps if everything else fails, I'll be able to get fresh division out of there. Damn vermin!
Any ideas about how to effectively exterminate it (them)?