Why Overlapping Residuals Drive Weed Control

Controlling weeds through canopy helps ensure your soybean crop isn’t facing competition for sunlight and nutrients, improves harvest efficiency and reduces the weed seedbed for future crop cycles.

That’s why overlapping residual herbicide activity is critical to controlling growers’ toughest weeds.

“The easiest way to reduce weed pressure for next year is to control the weeds that are in the field this year. Weeds are resilient, especially when they go to seed,” says Kenny Seebold, Valent’s senior director for research and development.

Perpetually troublesome weeds, such as Palmer amaranth, are particularly proficient at producing seed.

“Palmer amaranth produces a ton of seed that will fall to the ground and be part of that weed seed bank later in the season,” says Will Griffin, row crop segment manager for Valent U.S.A. “Controlling those weeds with overlapping residuals helps get the crop up and out of the ground with less weed competition. It also ensures that fewer weed populations will seed, eliminating problems down the road.”

Sequential herbicide applications with products containing residual activity help ensure that fields stay clean from preplant to plant canopy.

For Griffin and Seebold, that means beginning the season strong with a preemergence herbicide tank mix that includes Valor® or Fierce® herbicides, followed by a postemergence application of Perpetuo® herbicide.

What’s more, uncontrolled weeds have the potential to be heading when harvesting equipment is running, redistributing those weed seeds out the back of the combine and across the field.

“It’s not just about controlling the situation that we have in front of us, but how we forward manage those weeds that can go to seed,” Griffin says.

“Overlapping residuals bring the grower value, provide effective and lasting weed control, and manage resistance with multiple modes of action,” Seebold says.

Designing a weed control program that includes multiple modes of action keeps weeds in check, reduces weed germination rates and in-season weed pressure, and helps manage resistance.

And while cutting back on herbicide sprays or rates in a tough economic climate may seem like a shortcut to profitability, Griffin warns that you can’t save your way to prosperity.

Failing to apply the full labeled herbicide rate will not result in effective weed control and increases the odds of resistance developing.

“You’ve given those weeds enough herbicide to make them sick but not kill them. And now, you've got a survivor that may become resistant, creating a problem that’s going to rear its head two or three years down the road,” Seebold says. “It’s important to understand your weed population and pressure and your soil types, so that you're optimizing rates, timings and products.”

Adds Griffin, “It all adds up to dollars, and growers want those dollars to count. You want that bullet to hit.”