tansy and cinnabar

Asked July 17, 2018, 6:18 PM EDT

just wondering if there is a good ratio of tansy ragwort to leave for the cinnabar caterpillars to eat and reproduce so that they are always around. i don't have too much tansy left in my pasture but i really don't want to pull tansy that has the little cinnabars munching away.

Polk County Oregon integrated pest management weeds

1 Response

Thanks for the question. If you are hand pulling, just leave plants that you see larva on. Any plant clusters that you see without larva - PULL those. You may check the clusters that you see larva on every few days to see when they disappear and once you don't see them it is safe to pull without harming the populations of cinnabar.