To whom it may concern, I have noticed something biting the stalks of my peonies. I have sent a picture, currently I have wrapped the stalks in paper rolls. Any other suggestions?
Thank-you for contacting Toronto Master Gardeners with your question. Peonies are such wonderful flowers, and it is always a worry if something is attacking them! The posted photo is not clear enough for a positive identification of the cause of the damage to the stems.
That being said, unless you are actually seeing an infestation of something, I am wondering, if you are dealing with a disease rather than an insect. Peonies are susceptible to several fungal diseases which result in stem lesions. These disease symptoms look quite similar to one another. Most of these fungal diseases develop and spread in cool, wet conditions such as we have experienced this spring.
Take a look at the photos and descriptions in these articles (see attached link), to see if any match your situation. One of the most common peony diseases is Peony wilt, or Botrytis blight, as shown in this RHS (Royal Horticultural Society) article.
The Missouri Botanical Garden has a Useful list of peony pests and diseases which you may wish to consult as well.
Unfortunately, there are no “cures” for these diseases. The fungi can live in the soil for years. The best way to manage the diseases and minimize spread is to cut away any damaged plant material (always sterilizing your tools between cuts) and clear away any plant debris from around the plants.
Good luck, hope this helps.