Innovative controls: Kane family uses novel weed control, water development

Sheridan – The E Bar U ranch, owned and operated by the Kane family, hosted nearly 150 Wyomingites for the 2016 Environmental Stewardship Tour, where they showed attendees water developments, pipelines and an innovative weed control project on the operation.

The tour was held on June 22.

With miles of pipeline and improved water across the property, the Kanes have dramatically increased their carrying capacity, and at the same time, they have worked to treat a weed that plagues rangelands of Sheridan County – leafy spurge.

“We have a serious leafy spurge problem in Sheridan County,” commented Sheridan County Weed and Pest Supervisor Luke Sander. “It’s our most prolific weed, and bio-control is one of our main programs.”

Through the help of Sheridan County Weed and Pest, the Kane family uses flea beetles, a form of biological control, to tackle their leafy spurge problems.

Spurge biology

“Leafy spurge is a noxious weed that has been a huge problem for us for a long time,” commented David Kane, who owns and operates the E Bar U. “Through the years, chemical application was the only way to control leafy spurge.”

Bob Benjamin, retired supervisor of Sheridan County Weed and Pest who helped to start the county’s bio-control program, said, “One of my main jobs was working with leafy spurge. It is one of the most aggressive weeds in the West.”

Benjamin explained that leafy spurge can grow roots that reach 10 to 15 feet in depth, and when it is sprayed, often the entire root system is not killed, giving it an opportunity to come back.

“It also has an extensive taproot system and has a rhizomatous root that can generate new plants,” he said.

Leafy spurge seed heads also explode when they reach maturity, scattering seeds over a wide area.

“If we leave a patch of spurge alone, it can expand 10 to 15 percent every year,” Benjamin commented.

Traditional control

For many years, weed and pest districts have utilizes herbicides to control leafy spurge, but the control was incomplete.

“We had a chemical program that started in 1982, and we used herbicides in different rates sprayed by backpacks, helicopters and on foot,” Benjamin said. “It worked well, but we also had some difficult terrain. Then, in the late 80s and early 90s, we started using bio-control with insects.”

Bio-control of spurge

Benjamin explained that flea beetles can be used to control leafy spurge. Flea beetles are small bugs that are specific to the leafy spurge plant. They eat the plant, causing stress, and destroy its root system, effectively killing the plant.

“In 1991, we did our first release of the insects and had some results,” he commented. “We have several species that we work with.”

“We have two species of flea beetles here – Aphthona lacertosa and Aphthona nigriscutis,” Kane commented. “The A. nigriscutis is a black beetle, and they are a lot more prolific, from our experience.”

The bugs work by first eating the plant, which causes stress on the system.

Then, the females lay their eggs at the root crown of the leafy spurge plant.

“Females lay clusters of three to 15 eggs at the root crown,” Benjamin explained. “One female can lay 200 to 250 eggs. They lay in the soil for 12 to 19 days, and then they hatch into larvae.”

The larvae hatch and feed on the fine root hairs of the plant, inhibiting its ability to absorb the water and nutrients it needs for growth and survival.

“The larvae are active in the soil during the summer and fall – as long as the soil temperature stays above 45 degrees,” Benjamin said.

When soil temperatures drop, the larvae go dormant, and when the soil temperatures re-warm in the spring, the larvae become active and pupate.

“The adults emerge and generally live a month-and-a-half to two months,” Benjamin said.

Placing beetles

While bio-control using beetles is very effective, Kane also noted that it is a lot of work.

“We can’t just put the beetles out and leave them there,” he said. “We have to move them to new locations because they don’t fly.”

Rather, the bugs hop from plant to plant, so they must be gathered and transplanted.

Benjamin added, “We have to put the bugs out, monitor them and grow them. Then, we have use a sweep net and move the insects to the next site. It’s more work than just turning them loose and letting them do their thing.”

Kane emphasized, “It takes time, but it is imperative that this process continues in order to keep the population of beetles growing and spreading.”

Positive results

Kane said, “In 1998, we began using flea beetles for a biological solution to control this highly competitive, hard-to-control weed. To date, we have controlled thousands of acres of leafy spurge with flea beetles.”

He continues, “We’ve cleaned up entire drainages and only have little patches in some areas. Little patches don’t bother me.”

The bio-control mechanism is long-lasting and effective, Kane explained. He said that chemical control measures had to be repeated every four to five years, but the beetles have persisted on the landscape.

“When we first started, one of my big concerns was when I would have to do it again,” he said. “We’ve got places that we put bugs out 12 or 15 years ago, and when I see the spurge start to come back, I also see the bugs. The spurge will keep growing, but as long as we have bugs, we can keep it under control.”

“We’re always going to have leafy spurge here,” Kane commented, noting that the seed reservoir in the ground is too extensive to completely eliminate the species, “but we’re winning the battle and winning it big.”

Saige Albert is managing editor of the Wyoming Livestock Roundup and can be reached at saige@wylr.net.