Does anyone know what this is on my rhubarb plant? This is the only leaf that looked this bad. Some of the other leaves have a slight tinge of red on the perimeter of the leaf. They are brand new plants this year so I don't know if the leaves normally have a bit of red (Canadian Red Rhubarb). I'm worried it's Red Leaf Disease but hoping it's just a leaf that got infected with a fungus.
