Plum tree

A grafted Victoria plum tree that I'd  fan-trained, over about 4 years, has died this season. 

A few buds tried to burst in the Spring, but soon shrivelled.  I'd wondered if the rootstock had died. I've left it in place until now, but digging it up have found that the rootstock was actually starting to throw up some new shoots below ground level. Does anyone know why the grafted top of a tree would die off like this? All the other fruit trees seem happy enough (apple, pear and cherry).  I'd like to replace it, but might go for a Red Williams pear instead of a plum, if plums are susceptible to this problem. Thanks, G&R

This happened to my  eight year old fan trained Victoria plum tree. It didn't have silver leaf, but just gradually died back. Took it out and replaced it with a pear tree.