ANR advisors in action
I’m Rebecca Miller-Cripps and I work in the agriculture and natural resources program for the Central Sierra Multi-County Partnership for the University of California Cooperative Extension. And I’m standing here in front of a solid stand of yellow starthistle, also known as Centaurea solstitialis. Yellow starthistle is one of the worst economic and ecological pests in California today.
And the reason it is such a pest is that it is poisonous to horses; once they develop symptoms there is no treatment, and is fatal. And, it has infiltrated and established stands on, it is estimated to be at least 15-million acres of grazing and open landing in California.
So what can you do about it when you see yellow starthistle? On private property, you can pull it– hand pull it at any stage of its life. And that goes from the small rosettes all the way up to the full-sized plants.
This is known as full spiny-stage in full bloom. At this point, they are capable of making 75,000 seeds from one plant alone. So, you can pull it, or hoe it. When the plants are small, in what’s called the rosette stage, you can spray them with herbicide. RoundUp is effective but it will only kill the plant that is currently growing, and yellow starthistle sprouts again after every rain. So if you want to use an herbicide it might be wise to investigate a long term one with post-emergent and pre-emergent properties such as Milestone or Transline. Both of those require a permit from your agricultural department to use; there is also a new product on the market from Monterey Chemical called Starthistle Killer, and that’s available for residents on two-acres or less and it is registered for ranch and pasture use.
Now how did yellow starthistle get here? It came in, it’s believed, in the 1850s with the advent of ranching around Sacramento after the gold rush was over. And there was a new
feedstock known as the Chilean clover – we call it alfalfa. And it’s believed that yellow starthistle came in and infested seed stock. So one thing we are trying to do, and the program I’m working on, is called the Yellow starthistle Leading Edge Project. We are trying to establish an edge, a “Do Not Cross” line, where the advent of yellow starthistle will be stopped and we’ll each do our part to drive it away.