What is wrong with my lily
Cheryl, I haven't come up with anything yet, but I forwarded your pictures to a friend that has some 400 lilies (!) hoping that he may have seen this. I will get back to you when I hear from him.
For the time being I would remove and destroy the infected stalks.
My friend, also a Master Gardener, suggest that it could be a manifestation of leaf streak on the stems or something has attacked the roots. I see no evidence of leaf streaks in the photos. He suggests that you uncover some of the roots on the infected plants and look for bumps on the roots. The bumps indicate nematodes
let me know what you find.