Here is the link to the spring sickness info which I'm sure you have read. It really is the latest info however it was last updated in 2002.
http://web.ncf.ca/ah748/sstf.h...
Here is another website that talks about it. I don't know when it was last updated though
http://www.decadentdaylilies.c...
There is a thought that there are 3 possible causes of spring sickness
1. Bulb Mite
2. Fungus (leaf streak fungus)
3. Weather (being the least likely)
But since no one really knows the cause there is no way of knowing what to do about it I suppose
