I have both leaf streak and rust in my gardens. The leaf streak is especially bad this year. I just pull or cut the leaves for now. Some plants are more affected than others, but I haven't made the plunge into spraying with a fungicide yet. There are others in this forum that are very knowledgeable on such matters but I am not one of them. Most of the knowledge that I a have about daylilies, I learned right here on this forum.