Noxious weeds threaten ecosystem, economy
Tiny, white bunches of flowers span the test plot in St. Ignatius. To the untrained eye it looks like a field full of baby’s breath, but the land is full of whitetop, a weed plaguing Lake County and the entire state of Montana.
Summer is in full bloom, and so are weeds. They may look pretty, but what invasive weeds do to an ecosystem, and an economy, is downright ugly.
Jack Stivers of the Lake County Extension Office and Tom Benson, director of Lake County Weed Control (LCWC), are the area’s experts on whitetop. They estimate there are over 8,000 acres in Lake County with whitetop infestations, making up a significant part of the 84,000 acres of Montana affected by the weed. Whitetop creates a monoculture that chokes out all native vegetation. Stivers said this time of year the weed is at its most prevalent.
Stivers and Benson set up the whitetop demonstration site in St. Ignatius on land donated by Janine Allard. The site is comprised of 16 test plots treated in the spring and fall. The idea behind the test plot was a way to give recommendations for the average landowner dealing with whitetop, such as what herbicides work best and when to apply them.
Whitetop’s success as an invader is due mostly in part to its seed production and transport. Each plant can produce 1,200 to 4,800 seeds that can remain dormant in the ground for up to three years and have an 84 percent germination rate. However, Benson said a new invasion of whitetop could be quelled in the first season, before the plant has grown taproots.
The biggest barrier in exterminating whitetop, or any invasive weed species, is money. Herbicides are expensive and labor is time-consuming. Herbicide alone can cost $5 to $30 per acre. Plus, it can take years to eradicate the weed, even if a landowner follows a strict weed management plan.
“Whether it’s governmental or personal, there’s only so much money,” Benson said, adding that he wasn’t trying to condemn other agencies.
The cost of dealing with whitetop is why it is so important that everyone is on the same page, Benson said. But each agency is working within its own budget and management goals. The general public is aware of the problem, but the cost of eradication is too much to bear in a recession.
Benson and Stivers are most worried about Lake County’s economy. Agriculture is the county’s main industry, and if whitetop continues to spread, out-of-state ranchers may stop buying hay grown here.
“We would hate for Lake County to get a bad reputation for being infested or a risk,” Stivers said, adding that other regions could enact embargoes on hay mixed with whitetop. “It’s everybody’s problem not just the landowner or the cattleman or the ranchers.”
There could be a light at the end of the tunnel.
Several species of weevil are being tested as biological control methods, and tests look positive. Benson said the little insects would be a lucky break in combating whitetop.
“Nothing works on this plant,” he said. “That’s why a bio-control would be a saving grace.”
Though whitetop has been the topic of noxious weed discussions lately, there are several new invasive weed species infiltrating the pastures and rangeland of Lake County. Though a threat is present, there is hope that new invaders can be completely eliminated through the work of several dedicated organizations.
Blue weed was discovered three years ago near a logging operation on McDonald Lake Road. Experts believe it came from an infestation in Idaho or the Bitterroot Valley, south of Missoula.
June 24 – 28 has been designated as blueweed field week, where experts and volunteers from the National Bison Range Complex (NBRC), Montana Conservation Corps, LCWC and other organizations work to eradicate the weed from Lake County. Shay Piedalue, a wildlife technician at the NBRC, estimated there are 70 to 80 acres plagued with blueweed, but said surveys must be done to determine if blueweed has spread down Post Creek from the original site. Piedalue said their focus is to get rid of the weed before it gets out of hand.
Blueweed averages three feet in height with prickly stems and spotted flowers. Aptly named, the flowers of the plant are a dark, indigo blue. The weed spreads through seeds, not through a root system. Therefore it is not surprising that a single plant can produce 500 to 2000 seeds each year that can remain viable in the soil for several years.
Several herbicides can be used to treat blueweed, depending on the weed’s proximity to water. If the weed is growing on the bank of a canal, an aquatic herbicide is used, but if the weed is not near a water source a metsulfuron herbicide can be used.
Rush skeletonweed was found in Lake County in 2008. Benson said the problem was immediately addressed by multiple agencies. Like blueweed, rush skeletonweed has a field day set aside for monitoring and treatment. The infestation of rush skeleton weed is so small that management consists of clipping the weed and bagging it, effectively halting seed production. The rest of the plant is then sprayed with an herbicide.
The plant is a member of the sunflower family. Its thin stems have narrow, small leaves and its height of one to four feet tall give the plant a skeleton-like appearance. Flowering begins in early summer, with bright yellow flowers on the stem and branch ends. The stiff downward-pointing hairs on the lower four to six inches of the stem are an identifying characteristic of rush skeletonweed.
Benson said Montana is mostly rush skeletonweed free, but Idaho is overrun with the pesky plant.
LCWC offers a $50 reward to any person that identifies a new confirmed site of rush skeleton weed. Benson said even if it turns out not to be an infestation of rush skeletonweed and the person doesn’t get the reward, it means that the public is keeping an eye out for the weed.
He hopes LCWC will be able to offer rewards for blueweed sightings as well. Stopping these weeds from taking over rangelands will require help from the public, and LCWC relies heavily on the regular people to point out new infestations.
Piedalue said public outreach and awareness is a huge component of the work that she and her partner, biologist Amy Lisk, do at the NBRC. Other important factors in managing invasive weeds are cooperation and communication between management organizations. The PRISM Project was designed to bridge the gap between agencies and to prioritize areas and species in need.
The PRISM (Partners for Regional Invasive Species Management) partnership was created in hopes of increasing the results per dollar spent on invasive weeds through the collaboration of government and non-governmental agencies alike, as well as private landowners. Montana Fish, Wildlife and Parks and the Confederated Salish and Kootenai Tribes are also members of PRISM.
PRISM designates both rush skeletonweed and blueweed as high priority invaders, along with flowering rush, dame’s rocket, orange and meadow hawkweeds.
So far this has been very successful, Benson said.
Benson and Piedalue hope that through this collaboration Lake County can fend off new intruders and old offenders alike.
Groups also hope that together they can inform the community about the threat of invasive weeds.
“If I could improve one thing it would be education,” Benson said.
PRISM groups hope that together their agencies and an educated public can save and protect the livlihood of Lake County residents.
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