Rush Skeletonweed is a noxious weed that’s been in Idaho since the early 1960s. Now, it has infested more than four million acres of the state.
Amber Mendenhall, the Biocontrol Coordinator for the State of Utah, said the weed can outcompete the plants that should live in the sagebrush steppe.
"It will take over disturbed spots. Roadsides. A recent burn scar. And it's the first thing in. So it sucks up all the resources. Takes up every every bit of space. And none of your beneficial species come in."
You’ve most likely seen Rush Skeletonweed if you’ve spent any time in the sagebrush steppe – areas like the Treasure and Wood River valleys. It is a bright green perennial weed that can grow up to a couple feet in height, has a spindly appearance, and may have yellow flowers, if it is the right time of year.
Mendenhall said it will choke out native plants, causing a cascade of issues–from killing off pollinators, to game losing its food source.
"Wildlife won't touch this. Elk and deer will graze across an area like this. And if it is predominantly rush skeleton weed, they will quickly move on to another range."
The weed has a sticky internal sap that can gunk up agricultural machines, and Mendenhall said it also boasts structural features that can hurt anyone getting in contact with it.
"Skeletonweed is a unique plant in that it has these really nasty down facing hairs. And if you run your hand along there, you'll actually get little slivers in your fingers from these down facing hairs."
How do you combat it?
Eradicating this weed is not as easy as spraying weedkiller, said Joey Milan with the Bureau of Land Management.
"Even if we had all the money in the world, which we don't, even if we had all the personnel in the world to combat some of these invasive species. There's no way we have all the time and all the resources to, you know, spray herbicide over 4.3 million acres."
So, the solution? A cocktail of Biocontrols. Anna Web with the Forest Service explained the way biocontrols work.
"Biological control is utilizing one biological organism to control another biological organism."
While three biocontrols are being used at the moment on Rush Skeletonweed, one of them brought people from across the state and Utah for the chance of collecting them—Web explained the process.
"We wrangle those moths, put them all into some containers, and then go release them in other sites."
The moth, known by it's shortened Latin name Bradyrrhoa, or the Rush Skeletonweed Root Moth, brings organizations out year after year. The small white moths’ larvae are the main biocontrol aspect—they damage the skeleton weed by eating and exposing the roots of the plants.
This allows the plant to be susceptible to diseases, and can kill the plant. Releasing these moths in populations with Rush Skeletonweed can help manage and dissipate the invasive weed's population.
Jessica Fung from the Nez Pierce Biocontrol Center shared what she believes is the most integral part of the moth collection days.
"I think we're all collectively coming together to solve a problem that we're all experiencing."
In two days, around 1,200 moths were collected and then released at other sites with established Rush Skeletonweed populations to help control the invasive plant.
From Idaho Power, to Ada County Noxious Weed Control, and to some volunteers – everyone was there for the sole purpose as Anna Web with the Forest Service said – to wrangle some moths.
