April 2005 issue of the Cornell Flower Bulb Research Program Research Newsletter:
Growers of Oriental hybrid lilies, especially the cultivar ‘Star Gazer’ are familiar with an upper leaf “burn” that is commonly seen on ‘Star Gazer’ crops across North America and throughout the year. The disorder is characterized by necrosed (dead) upper leaves and by leaf curling, distortion or leaf tip burn (Fig. 1). The disorder is commonly found in greenhouse grown Oriental hybrid
lilies worldwide. In Holland, this disorder is translated as “leaf scorch”, but is a very different disorder than the fluoride-induced “leaf scorch” seen on ‘Ace’ Easter lilies in the 1960’s and 1970’s. To prevent confusion, we have named it “upper leaf necrosis”, or ULN.