Hi, Our rhubarb plant's leaves are curling and have brown and yellow spots - see photo. We live in Lakewood, OH 44107. The "Picture This" plant app on my phone is saying "temperature too high" and "disease infected," and to use a fungicide. I have removed most of the affected leaves and any that have dropped. The new shoots first appear healthy, but within a day or so wilt. There is another rhubarb plant next to the sick one, and it looks much healther, although it looks like something is eating the leaves, although I have not seen any insects on the underside of the leaves. We have had this plant for over 40 years, and it has never really had any problems, especially this one. Thanks for your help.