What type of gall is this on my dahlia? - Ask Extension
Hi,
I was pruning my dahlias and noticed one had a stem with lots of galls in it (the stem had died, probably from chilly nights). This doesn't look ...
Knowledgebase
What type of gall is this on my dahlia? #889430
Asked November 06, 2024, 11:58 AM EST
Hi,
I was pruning my dahlias and noticed one had a stem with lots of galls in it (the stem had died, probably from chilly nights). This doesn't look like crown or leafy gall and I suspect an insect did this. I cut into the galls and it looks like plant tissue with no visible larvae, however, there are some holes that may indicate whatever grew in the gall has now escaped. None of my other dahlias had this and my other plants look fine.
My dahlias are in growbags in full sun in a bed with other flowering plants. I haven't dug the tubers yet, so I'm unsure if they were affected by this as well. Do you know what species caused this issue?
Baltimore County Maryland
Expert Response
We're not familiar with this particular damage on Dahlia stems, but it looks like it might have been insect-caused, though we can't be certain. Some of the growths do look closer to adventitious root formation (a phenomenon common to a variety of plants, especially when they get humid near the stem due to frequent watering or reduced air circulation), though it's also possible that both phenomena were overlapping, root initiation and insect feeding. If an insect is responsible, we don't know what species it would be, though predict that the tuber(s) will be fine.
Miri
Miri
