We are excited to see Tansy Moth aka Cinnabar Moth show back up on the farm. We knew it existed but haven’t seen more than a few for many years. According to OSU, if the insects are presentit may still take many years for the population to build up and control the weed. “Tansy Ragwort was unintentionallyintroduced to Oregon in the early 1920s, and within 30 years, became a regional problem, killing thousands of livestock animals – mostly cattle and horses, and contaminating pasture and hay. The Oregon legislature commissioned the Oregon Department of Agriculture to implement a biological control program for the weed, and three insects – the cinnabar moth, a flea beetle, and a seed head fly – were introduced from 1960-1971.” (OSU Extension Catalog).

You cannot mow tansy, it sprouts up in tiny perennials when you mow. It is possible to spray it, if that’s how you roll, but that’s really not in our toolbox. You have to go out and pull each individual plant, or outcompete it with other species. The best way to control it is to promote healthy stands of grass and prevent overgrazing. We are working on it, in the meantime it is pretty exciting to get help from nature.