Biologic control of Star Thistle #591901 - Ask Extension


Biologic control of Star Thistle #591901

Asked August 25, 2019, 12:13 PM EDT

I understand there are several insects useful in biologic control of star thistle. Bangasternus orientalis, Eustenopus villosus, and Chaetorellia succinea. Where does one procure them and how does one apply them and when.

Josephine County Oregon

Expert Response

I have looked around online for the insects you list without much luck. I did find a few recaps of which insects seem to be doing the best against the yellow star thistle on the Oregon Department of Agriculture website for biological control of weeds. The Eustenopus villosus is doing very well on its own in southwest Oregon. The Bangasternus orentalis competes with the Eustenopus and is losing out. The Chaetorellia australis is said to be doing so well that further releases are unnecessary. The Urophora sirunaseva is a seed head gall fly and is well established in the Southwest of Oregon.

I would suggest contacting Carri Pirosko of the Oregon Department of Agricuture to see if she knows a source company. She is located in Grants Pass. Her phone number is 541-291-2680. Her email address is

Steve Renquist Replied August 26, 2019, 4:08 PM EDT

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