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Charles Kemp of Marshfield Forest Service Treats Kudzu Using Milestone VM, a Dow AgroSciences Herbicide, Tinted Blue

In 2006 the Kudzu Coalition became a member of the South Carolina chapter of The Southeast Exotic Plant Pest Council (SE-EPPC), namely SC-EPPC. This is part of its mission to spread the word about nonchemical kudzu control methods. An SC-EPPC Kudzu Control Task Force was created, chaired by Coalition Executive Director Newt Hardie. The task force was organized into two subgroups, one focusing on chemical treatments, the other on nonchemical treatments. Task force member Matt Nespeca of The Nature Conservancy acts as chair for the chemical side of kudzu control. Newt acts as chair for the nonchemical side. The Coalition felt that this was an ideal opportunity to learn more about using herbicides to control kudzu, and also to investigate combining chemical and nonchemical control methods. Therefore, the Chemical & Nonchemical Joint Study for Kudzu Control ("Joint Study") was established by the SC-EPPC Kudzu Control Task Force in 2007. The task force is responsible for maintaining and monitoring sites, scheduling treatments (chemical and nonchemical), and reporting findings to SC-EPPC.

Although the Kudzu Coalition was established to develop nonchemical treatment methods, it also believes that the use of chemicals is a valid approach that should be considered in any treatment plan. Here are the main objectives of the Joint Study for nonchemical and chemical practitioners. The last objective is perhaps the unique feature of the Joint Study!

  • Learn more about herbicides and nonchemical methods, respectively.
  • Learn how to coordinate their efforts, even though traditionally the practitioners work separately.
  • Directly compare the advantages and disadvantages of each treatment approach.
  • Learn how to combine the two approaches to best fight kudzu.

All participants volunteer their time, equipment, and other supplies. Dow AgroSciences has agreed to donate herbicides, and Marshfield Forest Service (Edgefield, South Carolina) has agreed to donate their services to apply them. Thanks to SC-EPPC member Travis Rogers with Dow AgroSciences for his help. Special thanks to Charles Kemp, owner of Marshfield Forest Service, who is personally applying chemicals. To summarize, here are the participating organizations for this Joint Study. There can be additional participants that are specific to each site, and these are shown on their respective web pages (see next paragraph).

  • SC-EPPC
  • Kudzu Coalition
  • Marshfield Forest Service
  • The Nature Conservancy
  • Dow AgroSciences

The Joint Study group chose two sites in Spartanburg, South Carolina. Beacon Drive-In, and Broome High School. Use these links to see detailed information about Joint Study work at these sites. Spartanburg is the base of operations for the Kudzu Coalition, so this gives Coalition volunteers easy access to the sites. Volunteers shall monitor the effects of herbicide treatment, and apply its own nonchemical methods, as follows.

Each site is approximately one acre in size. The first treatment applies herbicide over each entire site, following standard application recommendations. The Joint Study assumes that the herbicide treatment guidelines recommended by the manufacturer for kudzu are optimized, and will not "experiment" with the application process. Each site is then divided into two approximately equal portions. One portion shall continue to recieve herbicide treatments according to the recommended treatment schedule until kudzu is eliminated. This means a second herbicide treatment the following year, with possibly one more treatment the year after. The other portion of each site, already treated once with herbicide, is treated by Coalition volunteers to remove kudzu using nonchemical methods. No further herbicide treatments are applied to that portion. Nonchemical treatment proceeds until kudzu is eliminated in the treated area. Matt Nespeca tells us that six to eight weeks is probably enough time to wait after herbicide treatment before working the site with mechanical treatments.

The initial herbicide treatment ocurred on July 25, 2007, at both sites. The labeled rate for kudzu treatment using Milestone VM Plus (see fact sheet for more information) is 7 oz per acre, which was applied to leaves on ground kudzu using a hose reel sprayer from a truck capable of pumping large amounts of solution. Complete treatment coverage requires 100 gallons of solution per acre. Most of the solution is water. A backpack sprayer with 20% Garlon 4 in basal oil was applied to kudzu that hung high in trees ("basal bark method") because direct application of Milestone VM to tree leaves could harm the trees, especially if the trees are already under stress.

A rule-of-thumb for chemical treatment cost is $500 per acre per year, for 4 years. The total cost per acre is therefore about $2,000. The exact cost depends on several site characteristics, including the number of treatments that are necessary to eliminate the kudzu.

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The next herbicide treatment on the all-chemical-treatment portion is planned for July or August 2008. Non-herbicide treatment began on the single-chemical-treatment portion in October 2007, after the herbicide had enough time to fully act. Photographs and full details about the treatments are found on the Beacon Drive-In and Broome High School web pages, but here are general observations on the overall effects of the first herbicide treatment. About one month after treatment, most leaves and vines were brown and crumbling. However, there were places where green vines and leaves are seen among the dead plants, which appear as isolated "green streaks". See the photograph at left for an example (click on it for a larger image). Whether these leaves and vines were missed by the herbicide, or is new growth from formerly hibernating crowns, is unknown at this time. (Kudzu crowns covered over by a heavy layer of biomass "hibernate", but then sprout when uncovered and exposed to the warming sun.) In any case, this is an early confirmation that yearly herbicide treatments are necessary to fully kill kudzu, regardless of the effectiveness of the chemical.

During September 2007 Coalition volunteer and botanist Dr. Gill Newberry made the following observations: "Finding from the Beacon site. The plants that survived the spraying all have one thing in common, they all possess underground storage systems (tubers or bulbs). The yellow flowers returning to the patch are Jerusalem artichoke, and of course day lilies. Johnson grass also has tuber-like storage below ground and survives at the edge of the sprayed area. These were the only survivors that looked healthy enough to repopulate the area".

Bill Stringer, President of South Carolina Native Plant Society (NPS), examined the treated area at the Beacon Drive-In site in October 2007. Bill observed the following plants. They are not listed here in any particular order.

Opinions vary regarding whether each of these plans are "good" or "bad", with most of the controversy about pokeweed. On the one hand, pokeweed is a food source for wildlife. But on the other hand, the mature plant is poisoness to humans when consumed or by skin contact. Although people eat the young tender pokeweed greens, special food preparation is necessary. The Coalition recommends not touching pokeweed during kudzu work unless wearing gloves that block plant juices, such as latex gloves.

Because of the steep terrain along the bank behind the Beacon Drive-In, Bill suggests that the NPS lay in a blanket that includes embedded native grasses and flowers.

Keep checking back here for progress reports as the Joint Study proceeds!

Newt Hardie & Lou Adams
Revised July 2008