Metallic Green Beetle?
Location: About 200’ elevation, 1 mile north of Oregon boarder and 40 miles from Pacific Ocean
November 23, 2010 1:59 pm
Hello,
This is a lady bug sized beetle that I found on a plant that I think is St. John’s Wort.
The grass seed was grabbed when capturing the insect. They seem to drop quickly from the plant they are on when they are being pursued.
I have not found any identification for this insect. There does not seem to be any damage to the plant from this insect. I have seen a dozen or so on a plant at one time. They seem to mostly be around the flower clusters before blooming.
You have my permission to use these images.
I would also appreciate a reply if you know what this is and if it is a beneficial or an insect that should be watched.
Thank you for your time,
Jim Koepke
Longview, WA
Signature: Jim Koepke
Dear Jim,
Your beetle is Chrysolina hyperici, commonly called the St. Johnswort Beetle. It is an introduced species, that according to BugGuide, can be found from “Nova Scotia to Ontario, plus British Columbia and adjacent parts of United States native to Europe and Asia.” BugGuide also indicates: “Introduced to North America to control growth and spread of St. Johnswort, and to reduce the spread of native St. Johnswort disease (Colletotrichum gloeosporioides) Adults are more tolerant of cooler and wetter summers than the related Chrysolina quadrigemina, whose larvae and adults are killed by May frosts, and whose adult dormancy is disrupted by summer rains.” BugGuide describes its food and feeding habits as: “larvae feed during the night on shoot tips and basal and developing leaves of St. Johnswort (Hypericum spp.) adults feed in clusters during the day on flower buds and terminal leaves of St. Johnswort.” The British Columbia Government Forest Practices Branch website has this information on this biological control agent : “Early spring larvae feedings on fleshy new growth cause the most damage. This timing is the controlling key. Although adult feeding can be impressive, it has less impact than larvae feeding. Heavy fall feeding may cause some impact on the plants ability to overwinter.“
