Bayer Crop Science has extended its use of RNAi (ribonucleic acid interference) technology to corn rootworm control in its new VT4PRO line of hybrids.
The company first introduced RNAi to Ontario growers in 2024 in its SmartStax PRO corn hybrids.
Why it matters: Corn rootworm continues to pose a significant risk of yield loss across Ontario’s corn-growing regions so any additional option for controlling the pest can benefit farmers.
On July 9 near Tavistock, agribusiness dealers and salespeople learned insights about the newly released line of hybrids as part of Bayer’s annual It’s Grow Time research plot tour.
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RNAi technology works to disrupt the synthesis of a crucial protein during the insect pest’s developmental stage. RNA, or “messenger” chromosomes, carry the information about cell development from one site to another. Corn seed featuring the newly approved trait was first available in Canada last year in the form of SmartStax PRO, which offered protection against five different corn pest insects through three different modes of action.
Bayer Customer Solutions Lead Bob Thirlwall told the It’s Grow Time audience that the newly introduced VT4PRO line of hybrids – a few of which were available for 2025 planting in Ontario – enhances that offering by including a sixth targeted insect pest (western bean cutworm) and two additional modes of action within a single trait stack.
“Developed by Bayer to combat corn rootworm, RNAi technology…works differently than a soil-applied insecticide or Bt traits to control corn rootworm (and, therefore), can help increase a corn plant’s ability to defend itself against the billion-dollar bug,” according to Bayer’s website.
Along with corn rootworm and western bean cutworm, VT4PRO traits also offer protection against European and southwestern corn borers, fall armyworm and corn earworm.
For weed control, meanwhile, growers will typically find decisions in VT4PRO hybrids straightforward because they also feature Bayer’s Roundup Ready technology.
Short corn coming, but it will be a while yet
Next on Bayer’s corn horizon in Ontario, Thirlwall predicted, could be the company’s PRECEON short-stature hybrids. Already, he noted, a few small plots have been grown in the province along with numerous larger trials in the United States.
His colleague Brock Smith says Bayer has developed a natural trait in tandem with the PRECEON hybrids in the U.S. without the use of biotechnology. These varieties, however, lack consistency in terms of height of the plant and other characteristics. Smith expects the biotech version will be more popular due to the overall consistency.
On the Tavistock research farm, on July 9 a small plot of PRECEON grew approximately 18 inches shorter than its conventional counterparts growing adjacent. For anyone who eventually decides to switch some fields to short-stature corn, “it’s going to be a lot easier for guys getting in there with the sprayer,” Thirlwall said.
In major corn-growing regions of the US, meanwhile, reducing wind damage has also been a significant driver in the push to develop short-stature hybrids.
PRECEON probably won’t be released commercially in Canada until about 2030, Thirlwall said.
CRW4 is also in the pipeline, with 2030 also a likely timeline for commercial release in Canada. This has two brand new Bt traits that have never been used before in corn. It will be effective against resistant corn rootworm and will come fully stacked with other traits.
