Diseased Cosmos - Ask Extension
Judging by the pictures I've provided, can you tell me what may have caused my Cosmos flowers to become diseased and prey for ants? I planted them fr...
Knowledgebase
Diseased Cosmos #807071
Asked August 19, 2022, 2:46 PM EDT
Judging by the pictures I've provided, can you tell me what may have caused my Cosmos flowers to become diseased and prey for ants? I planted them from seeds mid May and they came up as healthy plants with pretty flowers. Over the last couple weeks, I noticed these growths on the stems and a nest of ants feeding on the foliage.
Washington County Maryland
Expert Response
Hi!
Would you be able to submit some additional photos showing the symptoms up close? It will be easiest to see them if you are able to slip a piece of white paper under the plant to get everything in focus. Please try to get a closer photo of the lump surrounded by ants.
Jamie
Thank you, Jamie, for your response. I did try to enlarge the pics I had sent but unfortunately then they wouldn't open after I enlarged. In addition, there is no opportunity for another photo shoot as I pulled up all these plants and discarded after taking the initial photos. I am sorry you are unable to pull enough detail from the photos I did provide to give any clues to what happened. I have been growing Cosmos from seeds for over 30 years and have never seen anything like what happened to these plants. That diseased stem is a real mystery.
ninicansee aka Denise
I am sorry we were not able to diagnose the issue from the photo provided. You did the correct thing by discarding the plant material. If you grow Cosmos again next year, please do keep an eye on them and send photos again if you see unusual symptoms. Another option would be to take a sample of a plant showing symptoms to your Washington County Extension office.
Christa
Christa
