Pink spots on rhubarb leaves

Credit: iStockphoto

Q: My rhubarb leaves have developed pink “spots”. Do you know what this is and how can I treat it?

I am not familiar with pink spots on rhubarb leaves since any fungal leaf spots tend to be small, round, brown spots. I believe what you are seeing is a combination of cultural and environmental problems.

Rhubarb tends to like a lot of manure (compost) around the base of the plant to retain moisture. Supplement moisture by deep watering during dry periods. Plants are heavy feeders so apply a complete fertilizer (higher in nitrogen than phosphorous and potash) at least three times a season (before growth starts in spring, after growth starts and after harvest). Use less fertilizer if using a higher nitrogen manure.