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Possible Phythophthora in garden bed #869923

Asked May 24, 2024, 11:54 AM EDT

I have what I believe to be ths phytophthora pathogen in my ranunculus and anemone bed. A small section of one row has yellowing, withered leaves, stems/buds that have sprouted up but are than drooping over just below where the flower will be, and when I go to pull the plants, it appears things are rotting at the ground level. I have a few photos but I’m wondering about the possibility of being able to get rid of this if that is indeed what is going on and if I should send in a soil sample. I had planned to plant other summer annuals in this bed once the ranunculus crop was done. I know it is quite a persistent fungus and don’t want to make a mistake dealing with it, also if there is a way to stop the spread to other plants.

Genesee County Michigan

Expert Response

Short of sending the plants in, it's going to be difficult to exactly diagnose what might be going on there. The symptoms do lead me to believe there is a rooting issue here. The dieback on the flower stalks could simply be due to lack of support the plants are getting from their affected root system. I do see some white powdery residue that could be mildew or botrytis impacting the flower stalks, but that is likely secondary to what is going on with the root system. There is also some coloration the leaves that concerns me about possible virus infection (anemone and ranunculus can get Impatiens Necrotic Spot Virus, INSV).

https://gpnmag.com/wp-content/uploads/05_P&D_GPN0712%20FINAL.pdf

https://www.apsnet.org/edcenter/resources/commonnames/Pages/Anemone.aspx

I would suggest that you dig up and send in a couple of the plants (the entire plant, roots and shoots), one showing the worst symptoms, one just starting to show symptoms.

Here's where you can find the information about submitting the sample:

https://www.canr.msu.edu/pestid/submit-samples/

https://www.canr.msu.edu/pestid/uploads/files/General_Sample_Submission_Form_May2022.pdf


Thank you for your question! Replied May 24, 2024, 12:46 PM EDT
Wow, Caitlin, thank you so much for the quick and helpful response! I know it’s hard to tell what’s going on simply from the photos but your initial suggestions are really helpful. I will definitely send in a sample. Especially because I had plans to grow other things in this bed and don’t want to exacerbate the problem. thanks again for your help today! 

On Fri, May 24, 2024 at 12:46 PM Ask Extension <<personal data hidden>> wrote:
The Question Asker Replied May 24, 2024, 12:53 PM EDT

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