Gala is a weak wood by any measure. Small wonder it has problems at the graft union.
I have yet to encounter difficulties with Gen30, but my soil is sandy and climate dry. It has been, so far, the best choice for conditions here. The only disappointment with Geneva 30 has been with Sturmer Pippin. Considering how Redfield has shot up and branched in one season on Gen202, I can’t help but wonder if Sturmer might be happier on that, even though Gen202 has been dubbed less productive…
So far, in my situation Gen30 for larger vigor trees has been working. Oldest graft is Rambour Franc made in 2012 and the tree is doing fine, with a rich (although averaging small) debut crop this season. High wind and fruit load posed no unusual problems with Rambour Franc on Geneva 30. RF tended to drop some fruit every day as ripening progressed.
On Gen 30 I also have Keepsake, GoldRush, Connell Red and Orléans Reinette (this a bud graft waiting for spring to prove itself)
On Gen41: Edelborsdorfer
Gen11: I believe this is Twenty Ounce/Blessing (what an apple!)
EMLA 26: new whips of Winekist and GoldRush
P2: Hunt Russet (Must graft from this for a larger root stock: amazing fruit!)
EMLA26: Bardsey, Wynoochee Early, and across the street: Winekist & Redfield
This is the first time I had heard Gen30 could be vulnerable to viruses. No evidence of it here.
VSOP: Thank you for posting that article about Gen41 and its weak graft unions. My historically oldest apple - and the oldest I know of with a hard date: 1175, Pforta Abbey near Naumberg, Germany - stands on Gen41. It is about five years old after grafting and looking strong. It is very upright. I had thought it might be good to leave it where it stands and graft from it for another, to put by the street. Now, having read that article, I think that is the best choice all around.
I bought it from Cummins, and do not blame them for a poor choice. We all do the best we can with the knowledge at hand. They may not have known about weak graft unions of Gen41 when they invested in it.