Tekiela: Controlling invasive grasses is more than just spraying the weeds
Laramie − Controlling invasive weeds with the mentality of “just kill the weeds” can do more harm than good, according to Daniel Tekiela, University of Wyoming invasive plants specialist.
Tekiela explains he began his career at the University of Wyoming at a time when people were excited about the use of bioherbicides as a solution to the growing issue of the highly invasive cheatgrass. However, when he looked into literature for the products, there was no research regarding the use of bioherbicides for cheatgrass control.
“I can’t recommend a product if there is no scientific evidence to back it,” Tekiela comments. “My job is to recommend solutions to land managers based on proven information.”
With no existing information, Tekiela set out to determine whether or not bioherbicides could effectively manage cheatgrass populations in various locations in Wyoming.
Using bioherbicides
“The thing we have to understand about using bioherbicides is that we are introducing living bacteria to the soil,” Tekiela notes. “The idea is the bacteria enters the soil and damages the roots of the plant.”
Tekiela explains because bacteria are living, the conditions at application need to be ideal to maximize the efficacy.
“It needs to be cool, wet and overcast,” according to Tekiela. “The bacteria are known to do better in cool weather, wet conditions that allow for better incorporation into the soil and the sun can damage the bacteria.”
After applying the bioherbicide at various rates and at various locations, Tekiela found it was not effective in controlling cheatgrass populations.
“One plot I tested had nearly perfect conditions, and when it was all said and done, the product still had no effect on the cheatgrass,” says Tekiela.
Prevention
“There is significant evidence suggesting that preventing invasions is more economically sound than waiting for it to become a problem,” Tekiela comments.
He blames the lack of prevention efforts, in most cases, on simple human nature.
“We as humans are really good at solving issues happening in the moment,” says Tekiela,“but it’s hard for most people to think about an issue before it actually presents itself.”
Tekiela explains prevention is the best tool we have in controlling invasive plants.
“Once an invasion becomes large enough, the only option is herbicide use,” according to Tekiela. “If we are prepared for the possibility of an invasion, we can explore other options, such as introducing perennials to compete with the cheatgrass.”
Tekiela explains, to be proactive, land managers must consider the activities that take place on their property that could introduce invasive seeds to the area.
“Construction equipment, livestock, migrating wildlife and vehicles can all introduce invasive seeds to the land,” says Tekiela.
“Even though it can be difficult to know when an invasion will occur, being prepared and proactive can prevent the plants from becoming a problem,” he adds.
Seedbanks
“One of the critical aspects to consider in weed management is the seedbank,” says Tekiela. “When we approach weed management, especially with cheatgrass, we want to target the seedbank because cheatgrass is an annual plant that can survive multiple years.”
Tekiela comments there have been recent studies in Colorado that suggest the seedbank of cheatgrass lasts approximately three to four years before it’s depleted.
“While this study is very exciting, the thing we have to take into consideration is how the environment affects a plant and its seedbank,” says Tekiela.
Tekiela notes, there is a major difference in environments between Colorado and Wyoming.
“The change in weather between Colorado and Wyoming seems almost instant when we cross the border,” says Tekiela. “When we cross into Colorado, the wind seems to stop, and the temperature rises.”
Tekiela compares Wyoming to a refrigerator in that it is drier, colder and preserves things longer.
“Unfortunately, we don’t have a good idea how long seedbanks last in this environment,” says Tekiela. “It’s important to keep weeds under close observation because missing just one year can put us back at square zero as far as weed management.”
The big picture
Tekiela comments, in the case landowners find themselves in a jam with invasives, they must look at the big picture.
“Having a ‘just kill the weeds’ mentality causes much more harm than good,” says Tekiela.
As an Extension consultant, Tekiela says he experiences many people only seeking a product to kill the weeds instead of looking at the bigger picture of their entire operation.
Tekiela recommends landowners reach out to Extension for help with weed management issues and consider the big picture.
“Every invasion is different, and there is no one-size-fits-all solution,” says Tekiela. “We have to look at the challenges and goals of the specific situation to curate an effective plan for weed management.”
Callie Hanson is the assistant editor of the Wyoming Livestock Roundup. Send comments on this article to roundup@wylr.net.
