What works today might not work tomorrow. This is especially applicable to those who manage industrial sites where total vegetation control is required, such as utility substations. Here, gradual overuse of certain herbicides is causing stubborn weeds like marestail, kochia and several amaranth species to slowly resist herbicides.
Although the introduction of new herbicides delivers a fresh start of sorts with renewed control, it’s only temporary if the same pattern of gradual overuse occurs, says Scott Flynn, field scientist with Corteva Agriscience™.
“When control issues begin, there’s a tendency with each treatment cycle to just increase the rate of the same herbicides in order to get the required level of control,” Flynn says. “It’s a short-term solution at best, because eventually the per-acre treatment rates and costs can’t be maintained. But more critically, this practice has been proven to give rise to resistance with many of the particularly tough weed species.”
Proper management makes all the difference
Flynn says the best solution is twofold. First, introduce new modes of action into your tank mixes, and second, maintain a consistent rotation of those mixes.
“Even the most effective bareground herbicides have a relatively short span of effectiveness without proper management,” Flynn says. “That means establishing a consistent rotation of bareground tank mixes that includes herbicides with unique modes of action — to both fight resistance and extend the effectiveness of current bareground herbicides.”
Herbicide resistance is not a new complication in total vegetation management. Repeated spraying of the same herbicides can result in the evolution of stubborn, resistant weeds. Flynn says the best way to halt that evolution is by introducing fresh chemistry into your tank rotations.
A good example of fresh chemistry is Cleantraxx® herbicide. Cleantraxx uses two novel modes of action to provide preemergence and postemergence control of more than 65 grass and broadleaf weeds, with up to six months of residual. Tank-mixing Cleantraxx with a combination of other chemistries with unique modes of action like Milestone® and Opensight® herbicides provides several new options for effective control in bareground situations.
