There are several significant reasons for keeping weeds and other undesirable vegetation along roadsides under control. For starters, their unsightly presence can create driver safety issues by inhibiting motorists’ line of sight. Excessive vegetation also can damage roadbeds by generating erosion, potholes and flooding due to improper road drainage off the surface. Finally, if left unchecked, invasive plant species can spread onto adjacent properties, leading to potential problems with nearby landowners.
As a district roadside manager for the Mississippi Department of Transportation (MDOT), Johnnie Thorne works to keep undesirable vegetation—and, by default, all of the above issues—in check along Mississippi’s roadsides. And one of the most effective tools he uses is herbicides.
“Herbicides have played a major role in managing our roadsides for years,” Thorne said. “However, more recently, I’ve begun implementing what I call ‘multipurpose’ herbicides into our program, as it condenses the number of products we have to hold in inventory. I also prefer to use products that have residual control, as this limits the frequency of applications, as well as reduces our labor hours.”
Thorne considers Opensight specialty herbicide such a multipurpose product. Recently, he began applying it in tank mixes to treat the plethora of undesirable plant species present along roadsides in his district, including bahiagrass, thistles, pigweed, ragweed, kudzu, honeysuckle, mimosa, blackberry and wisteria. Applications are made during the growing season primarily around bridges, culverts, guardrails and drainage ditches.
“We tank-mix Opensight at 3.3 oz per acre with Garlon 3A to treat bridges and other structures but also began tank-mixing it with glyphosate for roadside spraying to see how we can use it in our turf program,” Thorne said. “I like the fact that Opensight is versatile enough to do both, while effectively controlling our problem weeds, so I’ve been working it more and more into our program.”
Thorne, and others in his position with MDOT, relies on a partnership with Mississippi State University when it comes to evaluating what herbicides to prescribe. University researchers carry out trials with new herbicides that come on the market and then share that valuable information with MDOT for evaluation, which is how Thorne was introduced to Opensight.
“The university works with us to perform test plots with new herbicides, and I then look at the test plots to see which may have a place in my program,” Thorne said. “Even after their results come back, I typically take it a step further and do some additional, larger-scale test plots—usually a few miles, or around 30 acres. I do these larger test plots on the same highway so that I can compare herbicides and rates directly next to one another, which is what we did with Opensight.”
The partnership with Mississippi State University helps keep MDOT ahead of the curve with its herbicide recommendations, which in turn helps it meet the challenge of keeping the state’s roadsides secure and beautiful.
Wright is an IVM specialist with Dow AgroSciences.
Dow AgroSciences LLC