Knowledgebase

Insect ID question #911078

Asked July 23, 2025, 4:23 PM EDT

These are on cone flowers in the Duluth area. Are they beneficial or do they cause damage? Thank you

St. Louis County Minnesota

Expert Response

Looks like four-lined plant bug.  Most definitely not beneficial, although their damage is quite transient.  Read here:
https://extension.umn.edu/yard-and-garden-insects/four-lined-plant-bugs

These are finished down here in the Twin Cities, but probably not in Duluth.
Dennis in St. Louis Park Replied July 24, 2025, 2:05 PM EDT
Is it possible it is a  two-lined blister beetle (Zonitis bilineata)? The pictures look more like what I saw.

Two-Lined Zonitis

The BugLady spied this Zonitis bilineata (probably) tucked in between the leaf stalk and stem of a sunflower. It has no official common name, but its species name is Latin for “two-lined,” and that’s good enough for the BugLady. The “Two-Lined” Zonitis” can be found over much of North America except for the far Northwest and far Southeast. It appears early in the literature, being listed as present in surveys from the Agricultural College of New Mexico (1890), the Entomological Section of the Academy of Natural Sciences of Philadelphia (1817), and the Zoology section of the Report Upon United States Geographical Surveys West of the One Hundredth Meridian (1875). Adults are seen in grasslands, mainly on flowers in the Aster/Composite family, where they feed on the flowers and leaves. They are found in Wisconsin in mid-summer.



On Thu, Jul 24, 2025 at 1:05 PM Ask Extension <<personal data hidden>> wrote:
The Question Asker Replied July 24, 2025, 3:00 PM EDT
Yes indeed!  Your ID is more likely.  If it's a four-lined plant bug, you'd be seeing damage (the characteristic brown dots on the leaves).
Dennis in St. Louis Park Replied July 24, 2025, 3:25 PM EDT

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