Have any steps been taken in our neighborhood to biologically eradicate this weed?

Reporter
Sept. 4, 2010, 7 a.m.

Karla,

I wanted to thank you for submitting this report to the oregon Invasvie Hotline. Tansy Ragwort is definitely a species of concern for horse and livestock owners in Clackamas County, and I encourage folks to control Tansy whenever possible. Please review the links to Tansy Ragwort factsheets list below.

http://your.kingcounty.gov/dnrp/library/water-and-land/weeds/BMPs/tansy_ragwort-control.pdf
http://www.imapinvasives.org/GIST/ESA/esapages/documnts/senejac.pdf
http://extension.oregonstate.edu/catalog/pdf/ec/ec1599-e.pdf
http://www.co.thurston.wa.us/tcweeds/weeds/fact-sheets/Tansy.pdf

The biological controls for Tansy Ragwort are well established in Clackamas County. Thier are currently two tansy ragwort biocontrols currently being utilized the most familair being with the Cinnabar moth. While the Cinnabar plays a part in controlling Tansy Ragwort, it's use is limited. The tansy ragwort flea beetle is the more effective biocontrol, and is responsible for 90% of the biocontrol effort.

The larvae of the flea beetle munch on the roots of tansy ragwort, which weaken it and make it suscpetible to moisture stress. Unfortunately, due to the abnomrally wet spring and early summer we had this year, the impact the beetles had this year was minimized. Thats is why we are seeing a surge of tansy throughout the county.

I hope this helps to answer your questions. Please feel free to contact me directly if you have any additional questions. All the best,

______________________________________

Samuel Leininger
WeedWise Program Manager
Clackamas Soil & Water Conservation District
221 Molalla Ave. Suite 102
Oregon City, OR 97045
503-655-3144 x118
samuel.leininger@or.nacdnet.net
www.conservationdistrict.org
______________________________________

Samuel Leininger
Sept. 24, 2010, 4:26 a.m.