where the hosta plants doing very well where they where? if so this white webbing was in a symbiotic relationship with your hosta's. If they where doing poorly it my have been why your hosta's had issues.
Possible Root Rot >> http://www.veggiegardener.com/diseases/root-rot/i lifted 2 of my hosta plants to relocate them and underneath there was a white web like looking stuff , it smelled kind of musty.....i never gave it much thought at the time...then the more i thought about it i got a little worried because i moved them to a new flower bed i made...i am thinking if it is something bad it will contaminate my new flower bed... also my veggie garden is about 60 feet away from that spot.... any suggestions..?