The predatory bugs, beetles and in this case the lovely Cinnabar moth are in full force in summer months. Before the Cinnabar Moth was introduced to control Tansy Ragwort, this plant was the bane of farmers with grazing cattle or horses. animals commonly died upon eating Tansy Ragwort. Sheep are curiously unaffected.
This plant, a member of the Senecio family is highly toxic and grew with abandon throughout Western Oregon until the introduction of this moth by Oregon State University researchers in 1960. The moth is native to western Europe and parts of Asia. the moths seek our the tansy plants, lay eggs and in a few weeks their larval offspring are denuding the plants of flowers and foliage. It has proven a positive introduction to our region. Like all predators they don’t exterminate their source of food. We do notice a cycle of tansy showing up along the roadsides and the following year an increase in Cinnabar Moths.