oh for sure that stuff spreads GS , my NLxBB got it real good last time as well the GGXfriesland were pretty much a write-off ...but i ripped down everything bleeched the walls and put up fresh poly and gonna put some fresh genetics in there, hopefully the "virus" dosen't rear its ugly face again..... but i'd have to say that thrips are the Vectors of the virus....kill the thrips and you have a fighting chance.....and stress is also one of the most important factors.....