I do not personally grow either of these, but they are both bulbs, right? The vast majority of bulbs grow, bloom, and then "ripen" their foliage. You know it's ripening when it starts to turn yellow, then brown, then "die". It's not really dead, though. The bulb is just going dormant. It will reappear to do its thing again next year.

Could be botrytis. That link has some suggestions on what you might do right now to treat it and steps in preparation for next year to reduce the chance of it reappearing.

Since no one else has jumped in with an answer, I'll take a stab. First, just to clarify: none of the plants shown are day lilies (hemerocallis). The lily in question appears to me to be an oriental lily, not an asiatic. I don't know where you live (always helpful to include that info) or what your soil type is. From the picture it APPEARS to be iron chlorosis, lack of iron.There are foliar sprays you can use. Oriental lilies prefer an acidic soil in order to take up iron from the soil. They are much touchier than asiatics . If your soil is alkaline and you want to grow orientals you may have to do some soil amending. You can work peat moss into the soil and add soil sulphur to change the ph. One note, don't use to much peat moss as that can keep to much moisture around the bulb. Good luck. You might want to go to the website for the North American Lily Society, they have good information on growing lilies.

I viewed Yellow Jacket and also Yellow Blaze. They are quite a bit alike from their pictures. It is stated that Yellow Blaze is a late blooming asiatic, therefore it is possible that what I have is Yellow Blaze. Either would be a nice addition to the one plant I have and I am interested in pursuing either for Fall planting. I have a question for Pardalinum. You mention Cascade Bulb & Seed, Scotts Mills OR as being a possible source for Yellow Blaze. Since you are an Oregonian, you may know if this company was ever known as Cascade Valley Farms of Parkdale OR. I received some great bulbs from them in about '99 and about two years later when I tried to reach them, it appeared perhaps they were no longer in business. Their web site is inactive. Just a little question that surfaced when I saw the Cascade Bulb & Seed name. To Cailinriley, you suggested my lily may have been the beautiful Lady Fair which is pollenless, but mine had pollen. I welcome the new web site to which you directed me, called Parkland Perennials. They have beautiful photography and a great selection. We have some unusual varieties available through U.S. growers, but I've got to hand it to the Canadian growers, they have some lovely ones not readily available or unavailable, in the states for the most part. Thanks to all. It has been an interesting discussion. Everytime I go on a search, I find more new and interesting web sites to explore.