I had a number of Columbine that were affected by leaf miner last year. Am hoping to manage the problem without pesticides this year.
Is there a recommended course of action beyond removing affected foliage promptly, and do you think it is reasonable to expect that this can be managed without harsh chemical treatments?
Thank you for your question. Since I could not find an answer to your question in our archives, I looked at other Master Gardener sites to learn more. According to the University of Illinois Extension, you do not need to use anything to kill this insect. It causes minor aesthetic damage but will not kill the Aquilegia (Columbine). Illinois has a similar growing climate to ours.
https://web.extension.illinois.edu/hortanswers/detailproblem.cfm?PathogenID=148
You can find out more about what our Ontario Ministry of Agriculture, Food and Rural Affairs recommends for ornamental and native plants at
http://www.omafra.gov.on.ca/english/
Enjoy your flowers, even if the leaves look a bit chewed.