Every time I see this brightly striped yellow and black caterpillar it brings a smile to my face. It is the larva of the Cinnabar Moth. It stands out as a success story in the fight against invasive plants, and it's been done with a biological tool. In the 1950's I remember my Dad's concern and frustration in doing battle with the poisonous Tansy Ragwort in the cow pastures of our farm. In the 1980's I became aware of the use of the Cinnabar Moth to control the tansy when a State of Oregon Agriculture botanist asked permission to hang a trap at my home along Pringle Creek in Salem to be able to monitor the Cinnabar Moth population. The way the Cinnabar Moth helps in the battle against the Tansy Ragwort is that the larva thrives on devouring the foliage of the Tansy Ragwort. When we arrived at the coast this summer I noticed the Cinnabar Moth busy laying its eggs on the emerging Tansy Ragwort. Today while stationed on the Oregon Dunes Loop Trail waiting for hikers to arrive at the beach I noticed the larva busy devouring the Tansy Ragwort. In a period in time that we seem to losing the battle with invasive plants like European Beach Grass, Scotch Broom, and English Ivy, the success of the Cinnabar Moth stands out as a success story.
Cinnabar Moth adult- taken at Luckiamute Landing State Natural Area - June 2, 2013