LOW-TECH SOLUTIONS to big headaches form the heart and soul of the Brush Busters program. Essentially a repackaging of individual noxious plant treatment methods, Brush Busters has capitalized on simplified brush treatment recipes as well as recent developments in herbicide products and spray equipment.

Brush Busters Make Big Impact
With Small-Scale Treatments

By Colleen Schreiber

SAN ANGELO — The number of acres of mesquite treated annually in Texas using the "Brush Buster" program has topped 450,000 and that number continues to climb.

Drs. Darrell Ueckert and Allan McGinty, based at the Texas A&M Research and Extension Center here, are the engineers behind the hottest and fastest-growing brush management techniques being adopted by land managers today.

Brush Busters is nothing more than a revival of individual plant treatments packaged in a new, simplified way. For many years, ranchers and rangeland managers have been reluctant to use individual plant treatment, McGinty says, because they often assumed that treating individual plants is labor-intensive and neither practical nor cost-effective on large acreages.

The other hitch is that for so long, many, including McGinty and his counterparts, were taught not to treat an area until brush reached an "economic threshold" where the response at that point would pay for the treatment.

Brush Busters, by contrast, encourages ranchers to focus on preventive maintenance by concentrating on the smaller brush. Ranchers, he explains, have a hard time seeing the little brush. Most can only see the big brush and by then it’s too late and the only available options are airplanes and bulldozers.

"That’s why we’ve gotten behind on the brush problem," McGinty insists. "People don’t have the ready cash to spend that kind of money to aerial spray or bulldoze, so they don’t do anything or they just spray 100 acres a year on a 10-section ranch and they just continue to stay behind the curve."

McGinty relates the program’s concept to health care.

"HMOs will pay almost 100 percent for preventive treatments because in the long run it doesn't cost as much. Brush control is no different," he says. "It makes good sense economically because ranchers don’t have to put up so much capital to hire bulldozers and airplanes, and it makes sense ecologically."

The program is endorsed by the Texas Natural Resources Conservation Service and is supported financially by a variety of partners including Dow AgroSciences and DuPont. The technology is transferred through a number of venues, including videos, CD-ROMs and the TEXNAT website located at texnat.tamu.edu.

More than 100,000 brochures for treatment of mesquite alone have been distributed to land managers at various field day events. The brochures are also making their way into retail outlets where they're conveniently displayed alongside the recommended chemicals.

The team began work on repackaging the individual plant treatment technology in 1995. Changing land ownership patterns, ranch sizes diminishing, economical and ecological restrictions on herbicides, and the importance of wildlife to ranch revenue, McGinty says, were the impetus behind launch of the Brush Buster program.

The revival of individual plant treatment methods, Ueckert adds, came at an opportune time.

"The price of chemicals had driven up the cost of aerial spraying and many were no longer satisfied with its efficacy," he says. "People are always anxious to try something new. Brush Busters was not new technology. It's simply packaged differently."

One of the first things McGinty and Ueckert did in repackaging the technology was to simplify the recipes and reduce available options, particularly in the case of mesquite.

Brush Busters does away with the unnecessary jargon, eliminates the need for calculations, and packages the program in a easy to understand, easy to apply way. The recipes are tailored to fit the three, 14 and 45 gallon tanks, standard for the industry. The recipe clearly defines the exact amount of herbicide, and the amount of surfactant or diesel fuel needed for one of the three tank sizes.

The choices are narrowed down from pages of options in the case of mesquite to two, the two that the researchers have proven to be most effective. Brush Busters promotes only the most highly effective individual plant treatments available — those that routinely kill 76 to 100 percent of the plants treated.

Nothing is foolproof, but McGinty and Ueckert say fewer mistakes are being made.

"The biggest mistake people make is that they don't read what we give them. Instead, they listen to their neighbor or the sales clerk," McGinty remarks. "Everything mentioned in the brochures is important. If we mention it, you need to do it."

Another common mistake is using the wrong nozzle. Doing so, Ueckert says, causes unnecessary waste of a lot of chemicals.

Brush Busters, ranchers are finding, is ideal for maintenance control or for follow-up treatments. It’s also highly useful in improved pastures, as well as in areas of mixed brush, such as low densities of big mesquite with smaller ones coming in under them.

Some benefits of the program include: low risk to the environment because herbicides and other control methods are only applied to the target plants; better efficacy than broadcast spraying because herbicides and other control methods are applied more thoroughly and in greater dosages to the target plants; good selectivity, allowing ranchers to eliminate low-value or noxious plants while not harming those important to livestock and wildlife; and less expense than conventional brush-control methods when properly applied to the appropriate brush infestations.

Brush Busters offers two recommendations for mesquite control. The leaf spray (also known as high-volume foliar spray) is applied at a rate of .5 percent Reclaim plus .5 percent Remedy herbicide. The herbicides are applied in a water carrier with surfactant or in a diesel fuel/water emulsion containing five percent diesel fuel.

Brush Busters recommends adding a small quantity of Hi-Light spray-marking dye to the leaf spray to prevent workers from missing target plants or spraying the same plants twice.

The leaf spray method can be used from late spring (after mesquite leaves turn dark green and soil temperature at one foot is at least 75 degrees Fahrenheit) through September. The foliage should be sprayed until the leaves glisten, but not to the point of runoff.

The other method recommended by the Brush Busters program is the stem-spray method (also known as low-volume basal stem spray). The stem spray contains either 15 or 25 percent Remedy herbicide in a diesel fuel carrier. The stronger concentration is recommended for mesquite stems with a basal diameter greater than 1.5 inches and for those with rough bark. Stem applications are effective throughout the year, but the best application time is during the growing season when temperatures are high. The stem spray should be applied lightly but evenly, and completely around the lower 12 inches of all mesquite stems.

Brush Busters recommends a Spraying Systems ConeJet 5500-X1 adjustable cone nozzle for applying stem spray. The nozzle should be set to deliver a mist in a narrow, cone-shaped pattern. This setting minimizes herbicides use, cost and grass damage, and maximizes deposition of the spray mixture on the target (the lower 12 inches of the mesquite stems). The 5500-X1 nozzle delivers only about 20 percent as much spray as the nozzles that commonly come with backpack or hand-pressurized garden sprayers.

McGinty says demonstrations are the most effective way to transfer technology. For that reason, 15 large demonstration plots were established when the program was initiated. Additionally, most every county in the 23-county district area has at least three Brush Buster plots in their respective counties, one each for cedar, mesquite and prickly pear. The plots are evaluated annually.

The scientists recommend 400 plants per acre as the threshold for using individual plant treatments. They warn, however, that the number is general.

"Once it becomes more dense than that you probably need to go to a broadcast treatment," McGinty says. "But it also depends on the individual. For example, the rancher who operates 100 to 150 acres could not feasibly put up an airplane, so their threshold may be different from others. Or the economic threshold might be different for those who are trying to make a living off the livestock as opposed to someone who has outside income."

Experts say if the brush is treated at the right growth stage and the right densities, costs can be cut to about $10 an acre for mesquite. Maintenance treatments every five to seven years might only be half of that. Ueckert warns, however, that if one waits, say, 15 years to retreat, the costs could possibly be from $35 up to $100 an acre.

The efficacy, economics, labor-efficiency and acceptability of these individual plant treatments have been greatly improved by several new innovations, including all-terrain vehicles equipped with sprayers and electric pumps; lightweight backpack sprayers; and highly effective herbicides and spray-marking dyes.

Demonstration plots were used to determine the efficacy and cost efficiency of the treatment. Costs were calculated using $5 per hour for labor and $2.50 per hour for each all-terrain vehicle, plus retail costs for all the spray ingredients.

Each treated plot was evaluated at two years post-treatment. Two-years post treatment, the stem-spray method averaged 80 percent root kill with a range of 61 to 90 percent. The leaf spray also averaged 80 percent root kill and ranged from 61 to 93 percent. This is considerably higher than what can be expected from aerial broadcast applications.

Stem spray costs ranged from six to 15 cents per plant over five locations and averaged 11 cents per plant. High stem numbers are a limiting factor for use of the mesquite stem spray. Costs not only increase significantly, they also become much more difficult to estimate. The stem-spray method is also limited by heavy or tall herbaceous cover, which interferes with accurate placement of the herbicide/diesel fuel mixture on the lower 12 inches of the mesquite stems.

Leaf-spray costs were generally lower, averaging eight cents per plant and less variable than stem spray costs. The general range was from five to eight cents per plant.

Research shows that the leaf-spray method recommended by Brush Busters reduced the quantity of herbicide applied by 48 percent compared to conventional broadcast applications.

McGinty and Ueckert secured a three year contract with the Texas Department of Transportation, TXDOT, to develop a selective control program for mesquite in highway rights-of-ways.

The Brush Buster concept was the perfect solution, and the pair put together a package using automated mechanized delivery systems. Some, like the brush robot and the Scan Ray, were old technology that had never taken off, but the automated ATV sprayer was something developed in-house.

The same principles apply to the methods for cedar control and prickly pear control.

The control options for cedar include a soil-applied method using Velpar L or a leaf spray using picloram.

Velpar L should be applied to the soil surface midway between the cedar stem and the canopy edge at an undiluted rate of two milliliters for every three feet of plant height or every three feet of plant canopy diameter. Soil spot sprays should be applied with an exact delivery handgun.

The herbicide should be applied in late winter to mid-spring, ideally before expected rainfall.

For the leaf spray method, picloram needs to be applied at a one percent concentration in water. To ensure a thorough coating of cedar leaves, a commercial surfactant or liquid dishwashing detergent should be added to the spray mix. Leaves should be sprayed to the point of runoff. The herbicide works best in the spring and summer when cedar is actively growing.

Both methods work best on cedar less than three feet tall.

Hand grubbing for the resprouting redberry juniper or top removal for the nonsprouting blueberry juniper is another treatment option recommended in the Brush Buster program.

The number of acres of cedar treated using the Brush Buster program falls behind the number of mesquite acres, but both McGinty and Ueckert believe the program for cedar hasn’t nearly reached its potential.

Cost for the leaf spray method averaged 12.9 cents per cedar treated, ranging from seven to 19 cents per cedar. Average cost per acre treated was $20.90 with a range from $9.70 to $35.60 per acre.

Cost for the soil spot spray method averaged 6.4 cents per cedar treated and ranged from five to eight cents per cedar. Average cost per acre treated was $13.25 with a range of $9.60 to $16.90 per acre.

Brush Busters also has a program specifically targeting prickly pear. The program promotes only one "select" herbicide treatment: a pad or stem spray containing one percent Picloram and five percent diesel fuel.

The treatment method works on relatively thin stands of prickly pear, tasajillo, tree cholla, dog cactus and other species of cactus. The spray may be applied throughout the year. An absence of rain for extended periods after spraying may reduce plant kill.

Cost for treating prickly pear plants per acre was $9.22 per acre, and ranged from $2.50 per acre to $23.49 per acreor five cents per plant.

Brush Sculpting markets the Brush Buster technology in a package that specifically targets a wildlife audience. The concept evolved because of the growing interest in wildlife among the general public and landowners and the increasing economic value of wildlife to landowners.

McGinty and Ueckert are in the process of expanding the Brush Buster program to other plants like huisache and yucca. They also plan to expand to other areas geographically.

"We would like to see other states adopt the technology," McGinty says. "We know that there’s interest in New Mexico."

Both McGinty and Ueckert say they are pleased with the success of the Brush Busters program.

"We've had more impact from this technology than any other thing we've been involved with. It’s been rewarding to see something we've done be so eagerly adopted and used by ranchers," McGinty says.