Ironweed problem - Ask Extension
Can you identify the yellow dots on the bottom of my ironweed plant leaves?
Knowledgebase
Ironweed problem #849392
Asked September 11, 2023, 9:49 AM EDT
Can you identify the yellow dots on the bottom of my ironweed plant leaves?
Lake County Ohio
Expert Response
Dear Mr. Sipols,
Your ironweed has a common disease problem. Ironweed is susceptible to a fungal organism called rust. What you are observing are the rust fruiting structures. They emerge from the infected tissue to release more spores. There is no treatment that would be effective at this time. Fungicides need to be used prior to the infection process. Depending on the extent of the problem removing and destroying the infected leaves will limit the spores available for additional infections.
Respectfully,
Your ironweed has a common disease problem. Ironweed is susceptible to a fungal organism called rust. What you are observing are the rust fruiting structures. They emerge from the infected tissue to release more spores. There is no treatment that would be effective at this time. Fungicides need to be used prior to the infection process. Depending on the extent of the problem removing and destroying the infected leaves will limit the spores available for additional infections.
Respectfully,
