Hi Carolyn,

Tansy is an awful weed and I have received many calls about cinnabar moth larvae. The ODA used to have a program where people could get them but they no longer do. The reason is because they have conducted surveys and the moth and larvae have been found all over the Willamette Valley. 

Chances are you might have some already. Another thing to remember is that the ragwort flea beetle is the true workhorse behind tansy biocontrol. 

Here is an article that talks about biocontrol and general management of Tansy Ragwort. No matter what, a combination method is best, keep an eye out for beneficial insects and use mechanical and chemical methods depending on your goals.

I'd be happy to help you develop a weed or pasture management plan for tansy ragwort. Fighting the weed at the height of the summer is difficult, the ground is hard and dry and the plant has bolted and doesn't have as much leaf area. The best time to control it is in the fall and spring.

If you have follow-up questions, please email me directly at <personal data hidden>.