creeping jenny & sawflies - Ask Extension
My yard is creeping jenny and for several years I've been plagued by sawflies. Every year it has been effective to sprinkle diatomaceous earth and th...
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creeping jenny & sawflies #918287
Asked September 22, 2025, 7:52 PM EDT
My yard is creeping jenny and for several years I've been plagued by sawflies. Every year it has been effective to sprinkle diatomaceous earth and the creeping jenny quickly recovers. However, this summer, sawflies are a constant presence and I'm writing this on September 22. Don't they have a reproductive cycle? If you have any other suggestions for intervention, I prefer organic interventions. Thank you!
Hennepin County Minnesota
Expert Response
The creeping jenny sawfly (Monostegia abdominalis), has two or three generations, so its larvae may be present through most of the growing season. Learn more here:
https://www.inaturalist.org/taxa/358530-Monostegia-abdominalis
Controls include horticultural oil, insecticidal soap, neem oil, or spinosad. Defoliation occurs quickly, so frequent inspections (a season-long vigil in this case) are needed so controls can be applied before the damage is done.
Here's a reply to a similar question:
https://ask.extension.org/kb/faq.php?id=326526
