Here is some info on lilium diseases that may help:
LILIUM DISEASES

Stem canker causes cankers at the base of the stem. The roots decay as the disease progresses.

Chlorosis may be due to iron deficiency or overwatering.

Manganese and aluminum salts sometimes cause leaf scorch. One half inch of the leaf tips yellow then turn brown. Adding lime will reduce the browning.

Bud blast, is the drying up and failure of flower buds to open. Possible causes are root injury, cold soil, high temperatures during cloudy weather, and excessive shading.

The lower leaves drop if the plant receives insufficient light.

Funny, I have a couple of oriental lilies that look just like that. I have been wondering and here is someone else with the same issue. Only in one spot, maybe 4 altogether. Even a foot away other orientals (and asiatics too) are fine. I remember these same lilies also looking yellow last year too. What could affect such a small part of the garden? It was all amended at the same time and in the same way. We used peat (among other things) when first amending it 4 years ago but not since: have used purchased compost as top-dressing every year since then. (ArenÂt coffee grounds acidic? If so, maybe I should start putting them in the lilies instead of in with the hostas.)

Hi, I would like to share a tip - props to Peter?? who gave me the suggestion on this forum - use epsom salts. Sprinkle around the top of the soil or dissolve in water and water the plant and soil. Walgreens has epsom salts in big bags that suggest the amount to use. It worked like a charm on my yellowing leaves (chlorosis), because I have mine in pretty alkaline soil, and my lilies are bigger than ever this year. Good luck!!

I have Oriental Lilies, and its the flowers that the edges are turning brown. I live in Oklahoma City and it has been in the 100's but some are like coming out that way or immediatley doing so. And some are already falling apart, and they just came out this week. Pleases help. I was hoping to enjoy them at least two weeks not two days.

I have an asiatic lily ( just bought the bulb this spring) and as it grew it developed fuzzy edges on the leaves. Just fine lines along the edges of the leaves. Normal or disease?

That sounds more like a nutrient issue. This just came up for me, so maybe others will see it even though the post is very old. Too much phosphorous, the middle number in fertilizer, can cause the plant to not be able to absorb other nutrients like magnesium and manganese and sulfur. Or the soil could just lack one or more of those.