ROANOKE, Ill. – Corn rootworm management is being taken to the next level through a new generation of management options employing a revolutionary three-tiered approach. The science behind the new approach was a topic of discussion at the recent Bayer Crop Science 2021 Roanoke FOCUS tour.

Jim Donnelly, who is involved in Bayer’s current SmartStax Pro field trials, said the company’s product is the first trait to launch that employs a three-stage mode of action to combat corn rootworm. “Essentially we are taking our SmartStax products and Bt traits, those two modes of action, and combining that with a third mode of action. The benefit to farmers from that third mode of action is increased control and efficacy on corn rootworm,” said Donnelly, a technical agronomist for Bayer’s Dekalb and Asgrow brands for the past seven years.

Based in north-central Illinois, Donnelly’s clients are farmers located primarily north of Interstate 80 to the Wisconsin state line. Dozens of farmers attended Bayer’s tour at the Bayer Crop Science FOCUS site near Roanoke (Woodford County) Aug. 26-27 to hear Donnelly describe just what that third mode of corn rootworm management involves.

“All the previous modes of action revolve around using Bt proteins; this is totally different,” Donnelly explained. “With this one, essentially what we are doing is we have identified a particular protein that is crucial for the insect’s survival. We are blocking that process from occurring within the rootworm. This is something we have talked about for a number of years but is just being commercialized. The product will be ready for use next year, in limited quantities.”

SmartStax Pro is an RNAi technology, with the “i” standing for “interference.” Two Bt proteins within the product act below-ground to destroy beetles instantly after they consume root material. The RNAi technology controls beetles for longer periods of time and is effective for above-ground pest control, including protection from European corn borer, southwestern corn borer, fall armyworm, black cutworm and corn earworm.

Because RNAi technology works differently than a soil-applied insecticide or Bt-traits to control corn rootworm, it can increase corn’s ability to defend itself against corn rootworm, also known to farmers as “the billion-dollar bug,” according to the Bayer crop specialist.

“Bayer implemented a number of studies across the Corn Belt to test the product’s efficacy in various soils and climates, with a focus-on high pressure situations,” Donnelly said. “We looked at not only SmartStax Pro but at a number of traits on the market. We looked at current SmartStax, and basically whatever products growers can buy right now (to fight corn rootworm). We are still compiling that data, though some of the initial data we are getting are just as we expected to see – that SmartStax Pro is providing incremental control over SmartStax and other competitive traits that are on the market.”

With corn rootworm populations extremely high in 2021, Donnelly encouraged farmers to continue to rotate their corn crop with other cash crops to avoid overwintering rootworm beetles – even after SmartStax Pro becomes available commercially this fall. Since beginning its research, Bayer Crop Sciences has received a lot of queries from farmers wondering when they will be able to purchase the product from their input retailers.

“They are asking for the next trait in order to battle corn rootworm,” said Donnelly, who wouldn’t speculate as to what SmartStax Pro will cost over the current SmartStax product. “We’ll know more when we launch the products this fall.”

Though SmartStax Pro will be available in limited supply this fall, by this time next year the product will be rolled out in greater quantities, according to the Bayer Crop Sciences website.