Ultra Low-Volume Application

Managing a right-of-way (ROW) corridor is essential to ensure reliability and maintain healthy wildlife habitat. Halting natural succession at the shrub stage is fundamental to long-term environmental and economic benefits to utilities and customers. With thousands of miles of ROW and budgets to be managed in the United States, a cost-effective, efficient application method is The advantages to using this method include:

Less herbicide volume. We all want to be environmental stewards and, as part of a Quality Vegetation Management™ (QVM) program, using the lowest volume is key to stewardship.
Reduced risk of off-target damage. The ULV technique allows applicators to choose the target vegetation requiring treatment, without impacting surrounding desirable vegetation.
Productivity equals time and cost savings. Using less volume allows applicators to refill less often, resulting in increased productivity.


Vegetation Management Programs Using ULV


An emerging leader in the ULV technique is Arborchem Products Company. Owned by the Asplundh Tree Expert Co., Arborchem is the company's distribution arm for herbicides. In addition, Arborchem is a distributor of adjuvants, equipment and parts designed to help execute vegetation management programs.


The ULV technique requires the use of the THINVERT® Application System, designed by Waldrum Specialties, Inc. and offered by Arborchem.

The system has a unique ULV nozzle design combined with a proprietary fluid that creates a low spray volume application. It maximizes effectiveness, while minimizing off-target movement by reducing spray drift and evaporation.1


Asplundh applicators demonstrate and use the ULV technique with utility customers throughout the United States. They've found that ULV and THINVERT can provide maximum control while using a minimal volume per acre — both goals that many utilities try to achieve with their programs.


Joe Lentz, manager and technical expert with Arborchem, works with Asplundh personnel and customers to develop and implement programs. His goal is to use all the tools available to meet the objectives of long-term vegetation management. As a result, many contractors who reclaim a ROW with mechanical methods follow up with a QVM program using herbicides and the ULV technique.

While many in the industry still use mechanical control in ROWs, many others are starting to see and understand the benefits of low-volume herbicides and highly targeted application methods.


Asplundh has been instrumental in the development and use of ULV applications and THINVERT. It has been able to introduce the many benefits of ULV to utility customers across the United States.

So far, Asplundh has successfully used the ULV technique for co-op and investor-owned utility ROW applications at rates varying from one to five gallons per acre with backpacks, cut-stubble and broadcast using an all-terrain vehicle (ATV) or side-trimming methods of application.

How It Works


With ULV, applicators use the THINVERT application system, which uses herbicides mixed with THINVERT, an oil-based material. THINVERT RTU consists of Phytobland Paffinic oil blended with emulsifiers, surfactant and water to make a thin invert emulsion.


Being Phyto-bland means that the substance won't cause a phytotoxic reaction (burning) on the leaf surface. This is important because it allows the herbicide to stay wet on the leaf longer, creating a better opportunity for absorption at ULV rates. Once THINVERT RTU is blended with the prescribed rate of herbicide, it is applied with specially designed ULV nozzles.


“With a water-based material, a backpack nozzle typically applies about three pints of water per minute for effective coverage. The ULV application using the THINVERT nozzle with the same type of pattern requires only 10 ounces per minute for the same coverage and effectiveness,” said Lentz.


For ROWs that are in the first stage of a new vegetation management program, reclaiming the ROW with a mechanical method is necessary. “After one year of re-sprouting on distribution (15 to 60 feet wide), a ULV broadcast application will meet objectives in a cost-effective, low-profile manner,” said Lentz. A ULV Widecast™ nozzle system is mounted on the back of an ATV or Argo. This widecast application method allows utilities to put out 25-foot to 30-foot swaths, broadcasting at five gallons per acre.


“Some customers using the Widecast application method have seen up to 95 percent control of targeted vegetation. This is an excellent method for managing the ROW for future low-profile ULV backpack applications,” Lentz said.


Ultra Low-Volume at Work


Arsenal® herbicide from BASF Professional Vegetation Management is one of the herbicides Arborchem is using out in the field.


“Arsenal works very well with the ULV application technique because it's an enzyme inhibitor-based herbicide. We've had excellent results using this product with ULV THINVERT programs,” Lentz said.


Utilities using ULV and THINVERT with Arsenal have successfully controlled vegetation that typically re-sprouts one year after mowing. Using a combination of herbicides, utilities are reclaiming their ROWs, improving reliability and finding that the ULV control method is less visible, and creates less impact on desirable wildlife and plants in the ROW areas.


One such utility is Great River Energy, a generation and transmission cooperative based in Elk River, Minn. Since Great River Energy manages 1,800 acres of 500 KV line and 80 miles of ROW, a cost-effective but efficient vegetation management program is a top priority.


In July 2005, Lentz, Keith Erickson, manager of Asplundh operations in Minnesota and parts of the Dakotas, and BASF sales specialist Joel Roehl demonstrated the backpack and ATV methods of application to vegetation management specialists.


Great River Energy has been doing trials of ULV and THINVERT using a mixture of Krenite®, Escort® and Arsenal. What managers are finding is that ULV can provide great control of targeted vegetation and is helping the utility manage ROWs for future low-profile ULV backpack applications.


Other utilities using ULV and THINVERT include Laclede Electric Co-op in Missouri, Pee Dee Electric in South Carolina, American Electric Power (AEP) in Ohio, Exelon in Illinois and Pennsylvania, Oncor in Texas, APS in West Virginia, Rockland Electric in Tennessee, and others.


“Through this application system, we've been able to show people that herbicide applications can, and should, be part of a vegetation management program,” said Lentz. “When people see how we can target and control problem species, limit the impact on the desirable species growing on the ROW, manage the land for wildlife and do it all cost-effectively, they're interested.


“During the winter and spring months, I typically give three to four presentations per week as part of the training process for our Asplundh personnel, Arborchem customers and utility vegetation managers,” Lentz added. “And interest is still growing.”


Asplundh credits its co-op and investor-owned utility partners across the United States. By coordinating with these customers, the ULV application technique has been tested and perfected in real-world situations by working utilities — utilities that rely on their vegetation management programs to be effective so that they can provide cost-effective, reliable power to customers.

1Courtesy of Waldrum Specialties.