For farmers who grow continuous corn, corn rootworm is a pest that growers must deal with on an annual basis. And over the decades, growers have learned you can’t really rely on one single tactic.
“We had the insecticides we developed in the 70s and 80s that were very effective, but we learned over time that really a single tactic like that wasn’t going to work,” said Gail Stratman, Regional Technical Manager, FMC. “We came along with the genetic traits or the GMO traits here in the early 2000s and they proved to be very effective, but we have found over time as we have continued to overuse those, we are going to have issues and so we start to see rootworm populations that are able to overcome that BT resistance.”
Stratman said growers need to get back to the basics and use all of the tools in their toolbox. While FMC has had success for a number of years with at-plant soil insecticide, Capture LFR, they’ve recently added another tool, an “adulticide,” that directly addresses adult Western corn rootworm.
The active ingredient in Steward EC insecticide, indoxacarb, is an integral part of an integrated pest management plan to manage corn rootworm resistance. Resistance has been reported in the previous three major insecticide classes used for Western corn rootworm beetle control: organophosphates, carbamates, and pyrethroids. However, indoxacarb has no known resistance or decreased sensitivity.
By working through ingestion and contact activity, Steward EC insecticide provides fast-acting protection within four hours of ingestion to prevent impact on yields from reduced pollination because of silk clipping. It is also easy on beneficial mites and insects, preventing flares from spider mites and other insects.
“As we think about corn rootworm and we think about some of the issues we run into, the main thing is we need to learn from our past mistakes,” Stratman said. “As we have seen, corn rootworm can overcome insecticides, can overcome traits so we just need to instill all the products whether that is at planting insecticides, traits, or adulticides in our operation to make sure we are effective in managing this rootworm pest.”
And Stratman says now is the time to put a plan together for #Plant19.
“As we go into next year, it’s really about assessing where I had success this year and maybe where my shortcomings were from last year. I want to evaluate those fields and see where I had high populations of corn rootworm this year because that is where I’m going to have problems next year,” Stratman said. “And how do I employ tactics there? Maybe on a field where I don’t have a high population I could use a single tactic or a couple of cheaper options or maybe I don’t need a BT trait there at all, and I can use a soil insecticide and maybe come back with adulticide later in the season. Basically, I want to figure out what fields I’m going to have problems with next year and really focus on how I’m going to attack those pests at that time next spring, because that is where I’m going to need more investment.”