No Place To Hide

A tall, dense stand of Carrizo cane (Arundo donax) along the Rio Grande can hide anything from illegal immigrants to Mexican cattle carrying ticks that transmit Texas fever. Ranchers and government officials have teamed up to tear down this wall of vegetation, and restore native grass and willow along the border.

A 100-Year War

Twenty-foot-tall Carrizo cane grows so thick along the Rio Grande River that even a half-ton steer can disappear within its green shroud. In the Texas border town of Laredo, that can translate into significant economic risk for cattle operations.

Normally, a stray steer wouldn't cause so much concern, but Mexican livestock often carry ticks that transmit Texas fever, a disease caused by protozoa that destroys a cow's red blood cells and can result in widespread fatalities. In fact, around the turn of the 20th century, Texas fever wiped out nearly 90 percent of cattle herds and halted the historic cattle drives.

Unlike the "old days," Texas now employs U.S. government cowboys to ride the Texas riverbanks on horseback looking for cattle crossing this natural border. These "tick riders" are responsible for keeping stray livestock off private ranch property. But with a wall of Carrizo cane obstructing the border, they have a tough time spotting livestock, let alone signs of recent cattle crossings.

In Webb County, Texas, government experts and private ranchers are working to ensure they never experience the devastating effects of Texas fever again. They have joined forces to control Carrizo cane and provide better visual access to areas where Mexican livestock might cross the border.

The Right Partnerships Support Independence

Texans are known for their fiercely independent nature, and many landowners and managers do not believe the government can solve the Carrizo cane problem alone. That's where Johnny Oswald comes in. As the water enhancement program supervisor for the Texas State Soil and Water Conservation Board, it's his job to help landowners connect with experts and find contractors to help battle the Carrizo.

"Texans like to make their own decisions about land management practices," Oswald said. "Working through soil and water conservation districts, we provide technical assistance and information to landowners and managers to control invasive plants on their properties."

One of these managers is Jim Mutz, who oversees the 9,000-acre Rancho Blanco nestled along the edge of the Rio Grande in Webb County. The ranch is home to 500 head of cattle that have been quarantined three times in the last decade because of possible fever tick infestations.

"During quarantine, the entire herd is brought in using helicopters, and the cattle are dipped or vaccinated monthly throughout the nine-month quarantine," he explained. "Just one missing cow forces a restart of the process, because we have to prove that 100 percent of the herd has been vaccinated. It's a huge expense."

Mutz and the owners of Rancho Blanco enlisted state officials, Quality Vegetation Management™ (QVM) Certified Applicators and BASF to get the cane under control on their property, and are now showing neighboring landowners the path to success.

Texas-Sized Recipe for Control

Charlie Hart, Ph.D., of the Texas AgriLife Extension Service, has spent much of his career searching for control solutions for riparian invaders like Carrizo cane and saltcedar. His work with government agents and private landowners in Texas is helping develop programs that match budgets and needs for technical support (see sidebar).

"There's no silver bullet for Carrizo cane control," said Hart. "It takes a long-term investment and appropriate use of all the available tools to make a lasting impact." The density of the cane on a particular site dictates which tools will be most effective and in what combination.

In monocultures, a herbicide treatment is often the right first step for control. But in mixed stands, starting with biocontrol agents that feed only on the cane might be an option. In many cases, mechanically removing or burning the dead cane litter will give native plants a better chance to re-sprout, but those methods must be properly timed.

"The research Dr. Hart and others have done to put together a control program in Texas is invaluable," said Oswald. "His experience and hard work make him a trusted resource for landowners who want to control cane."

"The tank mix for Carrizo cane is well established," said Hart. "The important thing is timing of the treatments, and that the applications get done right."

Provine Helicopters, a QVM Certified Applicator, applied Habitat® herbicide at Rancho Blanco in August 2007 on all 6.5 miles of riverfront (approximately 120 acres). In South Texas, aerial applications are completed from late May/early June through the first frost, typically in November.

"Our spray technology gives us great accuracy, and we take advantage of the wide application window to spray only on optimal weather days," said Sherrod King of Provine Helicopters.

Jim Crosby of BASF has been working with Hart, Mutz and King on Carrizo cane control pilot projects using herbicides. "Part of the reason Habitat is the best choice for Arundo control is that the majority of the brush species along the river are tolerant to the treatment," said Crosby. "In addition, legumes are not affected, and grasses and forbs will naturally revegetate the area after treatment."

Many landowners initially voiced concern about using herbicides along the river. But Oswald can confidently tell them that, with the right program and application, there's no need to worry.

"With a herbicide such as Habitat, which is labeled for aquatic use and has been researched so well by Dr. Hart, it's easy to reassure landowners," Oswald said. "Especially when they use top-notch applicators to apply the product the correct way."

King echoed the importance of using the right applicator. "When you choose a QVM Certified Applicator, you know you're getting an operation that will be there for you if there's a problem," he said. "We stand by our product and the service we provide."

QVM Certified Applicators recommend using branded products over other alternatives, providing landowners with an additional degree of assurance that the products will work. "BASF stands behind Habitat, and will work closely with landowners if there are any unexpected results," said Crosby.

Restoration on the Rio Grande

To reduce the chance of soil erosion along the riverbed, Hart emphasized using Habitat to control the cane and then waiting for the litter to dry before removal.

"It's what's under the soil that builds and holds it in place, not emerged plants," he said. "Spraying keeps the underground organic matter intact while the cane is drying out and other plants are resprouting and rebuilding roots."

Once spraying is complete, litter should be left in place for 12 to 18 months. In many cases, native revegetation will occur naturally, and cane debris can be left alone to decompose naturally, mechanically removed or burned off. If your goal is wider site distance or faster revegetation by native species, consider shredding cane debris.

In areas where significant reinfestation is expected, university researchers are experimenting with wasps and flies that feed only on Carrizo cane and may hold the line while native plant communities are restored.

While this long-term strategy is still in its pilot phase in Webb County, Oswald notes that the cane does not readily reseed in stands where litter remains. Without seed-to-soil contact and access to nutrients, water and sunlight, the plants have little chance of survival.

At Rancho Blanco, Mutz plans to cut out the litter in strips and replant with low-growing native grasses that work well in the sandy soils along the Rio Grande. "We expect some of the natives to come back on their own, but we don't yet know how much damage the cane has done," he said. "We'll decide where to put the strips once we remove the litter."

Seeing Clearly to Stop Invaders

Mutz is already seeing a dramatic increase in sight lines and access to riverfront areas. "We've gone from a very minimal ability to see what's happening on the river to about 75 percent to 85 percent visibility," he said. "That's a major improvement, and will hopefully keep us out of quarantine."

"Habitat treatments can turn miles of monoculture into diverse native ecosystems," said Hart. "The pilot treatments at Rancho Blanco are a major step toward empowering landowners to treat Carrizo cane, helping the tick riders do their job and keeping fever ticks under control."

Funding Carrizo Cane Control

The Rancho Blanco Carrizo cane pilot treatments were funded partly through the Natural Resources Conservation Service, which is working with Hart and Oswald on treatment protocols. While no specific funding for Carrizo control is established in current federal programs, Farm Bill programs like EQIP (Environmental Quality Incentive Program) and WHIP (Wildlife Habitat Incentive Program) can be used, and other conservation programs have potential.

Hart helps landowners find funding opportunities, but points out the challenges in securing money for the long haul. "Funding has to be the first step in a restoration project, but it is very difficult to find funding that will last the life of a Carrizo cane control program," he said. "Because of state and federal budget cycles, it's hard to instill that vision in government leaders. But there is plenty of room to grow funding, and we're always on the lookout."

With 99 percent of land owned by private individuals in Texas, Oswald notes that any money will be used for partnerships, not overall support. "Landowners still will be making autonomous decisions about control programs — we just provide a starting point and as many resources as we can," he said.

For more information on funding for invasive weed control, contact your local NRCS office or visit

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