Green Dock beetles on Red Twig Dogwoods

Question: My Red Twig Dogwoods are covered this week with thousands of small, 5-7mm long, shiny green beetles that were eating the leaves away.  Are these Green Dock beetles, and are they endemic?  I have not seen them before in my 40 years of having Red Twigs.

responder: Jefferson County Extension of Colorado State University  Replied May 23, 2023, 1:55 PM EDT
response: thanks for contacting the Jefferson county extension plant clinic. Gastrophysa viridula is not commonly associated with Dogwood. It would be useful for you to bring a sample of the insects and the damaged leaves to the extension, 15200 west 6th ave golden 80401. The charge to identify insects is $15. Pat B, Jeffco plant clinic

responder: The Question Asker Replied May 23, 2023, 2:34 PM EDT
response: Can I just drop the samples off at the Golden address without requestion identification?  I mainly wanted to improve your database.    Valan Cover                        CASA Advocate for Children   Cell<personal data hidden>     Office<personal data hidden>          From: ask=<personal data hidden> <ask=<personal data hidden>> on behalf of Ask Extension <<personal data hidden>> Sent: Tuesday, May 23, 2023 11:55 AM To: vcover <<personal data hidden>> Subject: Re: Green Dock beetles on Red Twig Dogwoods (#0101438)

responder: The Question Asker Replied May 24, 2023, 3:55 PM EDT
response: Requesting...   Get Outlook for Android  From: V COVER <<personal data hidden>> Sent: Tuesday, May 23, 2023 12:34:02 PM To: Ask Extension <<personal data hidden>> Subject: Re: Green Dock beetles on Red Twig Dogwoods (#0101438)    Can I just drop the samples off at the Golden address without requestion identification?  I mainly wanted to improve your database.    Valan Cover                        CASA Advocate for Children   Cell<personal data hidden>     Office<personal data hidden>          From: ask=<personal data hidden> <ask=<personal data hidden>> on behalf of Ask Extension <<personal data hidden>> Sent: Tuesday, May 23, 2023 11:55 AM To: vcover <<personal data hidden>> Subject: Re: Green Dock beetles on Red Twig Dogwoods (#0101438)

responder: Jefferson County Extension of Colorado State University  Replied May 28, 2023, 12:57 PM EDT
response: Hi Valan - We're a group of volunteers at Jeffco Extension, and our program is jointly supported by Jefferson County and CSU, but also by the services we provide in the lab. That being said - we appreciate your photos and questions and definitely take note of the inquiries we get from the public - so thank you!  On seeing the photos my first thought was that they look like flea beetles.  One type of flea beetle are the rascals that suck the juice out of tomato plant leaves leaving brown skeleton-looking areas.  Here is a link from a great insect online group called BugNet - apparently there is one called the Dogwood Flea Beetle: https://bugguide.net/node/view/599571.  I've not heard of them in CO and not immediately finding any information on its' prevalence here, but they appear to be common in the Pacific Northwest - maybe our moist spring helped their numbers this year.   A good clue that they're some sort of flea beetle is to shake a branch.  If they jump around, their likely flea beetles.  It's hard to kill them as they reproduce quickly, but they are easy to discourage by spraying the plants with insecticidal soap.  You can make your own concoction of this by using 1tablespoon of liquid soap (dish soap, like Dawn or Dr. Bronner's liquid castile soap) per quart of water.  You'll need to spray every couple of days and after rain - hopefully as the summer warms/dries out they'll leave this plant. This treatment would probably work on whatever brand of beetle it is.  If you have further questions, or if they begin to seriously damage your plant feel free to write back.  Thanks again for contacting us. Jeffco Clinician Annette