Updated Nov. 6, 2019
Western bean cutworm is now the most economically significant pest of corn in Ontario, and its rise took seed companies by surprise.
As a result, genetically engineered resistance to western bean cutworm (WBC) has been slow moving into the market.
WBC larvae feed on the silk of corn ears, and also burrow through the side of the ears. They don’t create a lot of yield loss, but they create the risk of increased mycotoxins getting into the corn and lowering quality.
Why it matters: Western bean cutworm is now a problem in corn across Ontario, Quebec and the Maritimes, quickly spreading from pockets in southern Ontario several years ago across the region.
There’s only one genetically engineered trait resistant to WBC, the VIp3 or Viptera trait from Syngenta. The largest seed companies had avoided the trait, instead relying on their own Bt traits to control corn insect pests. But it turned out they didn’t control WBC.
Now the other seed companies are trying to catch up and Syngenta is quickly regrowing its seed corn hybrid line to take advantage.
The Viptera trait has had a strange history.
Many companies in the industry avoided the Viptera trait as it was released early into the market by Syngenta, before Chinese approval. That meant some corn with the trait ended up in China, resulting in significant loses for American farmers and lawsuits against Syngenta. The trait was pulled from the market for a time.
There was no question about the efficacy of the trait, just concern over its approval in foreign markets.
Now, it’s a trait that Ontario growers can’t get into their fields fast enough. When western bean cutworm arrived in the province, it was assumed that traditional Bt trait stacks would protect against it. But it was soon found in monitoring by Jocelyn Smith at the University of Guelph’s Ridgetown College that those Bt traits had no protection against western bean cutworm.
That’s meant farmers have had to rely on precisely timed fungicide treatments to control the pest.
Now that the need has been demonstrated in this market, the larger seed companies like Pioneer and DeKalb have trait-protected corn now available, but only in the farthest south of the province.
Syngenta, however, is aggressively rebuilding its NK seed brand corn offerings, says Dan Wright, who recently joined Syngenta as head of seed for Canada, to help build its seed offerings.
“I’m excited about where our corn business is going, with new investments we’ve made in people and testing,” he said.
Syngenta will have 13 corn hybrids available for 2020 from 77 to 104 growing days rating, with the Agrisure Viptera trait. That will cover most of the province. Four of those will also include Syngenta’s new Duracade trait for rootworm control.
Horizon Seeds has the second-most hybrids available with the Viptera trait at 10 for the Ontario market. That includes four new hybrids coming to the market.
Jessica Van Laecke, Horizon’s marketing and communications lead, says that the company thought that using more Viptera traits made sense as few other companies were offering them and that WBC was becoming more of an issue.
Corteva — formed by the merger of DuPont and Dow AgriSciences — on the other hand, has only one hybrid with the Viptera trait in it in each of their Pioneer and Brevant seed brands.
Dave Harwood, technical services manager with Corteva Canada says Pioneer’s trait stack is called AcreMax and its hybrids with the Viptera trait are called AcreMax Leptra.
He says the protection with the Vip3 trait is “exceptionally good.” The two hybrids available from Pioneer and Brevant are 99 and 110 day maturities, so only really used in the warmer parts of the province.
That’s a reflection of the fact that the hybrids were developed for the southern U.S. Corn Belt, says Harwood.
“As the years go by, we will see more earlier maturities,” he says.
At DeKalb, now at Bayer company, Derek Freitag says the company will have two new hybrids for 2020 planting at 2700 and 2750 heat units. He says they’ve been concentrating on getting hybrids available in the London area as that’s where the pressure first started.
“It’s a trait we know growers are looking for in many genetics,” he said. “What has changed in last two or three years is the spread of WBC and demand for traits for it.”
Doug Alderman, of Pride Seeds, which has recently turned 70 years old, says they expect to have new insect-resistance traits in their hybrids soon, including a WBC tolerant hybrid available. He said the company is looking at some of the new insect tolerant traits, including Tricepta from Bayer, which includes Bayer’s Yieldguard VT Doublepro and the Viptera trait.
“Not only do the traits have to work, but the hybrids have to be top-of-the-line performers,” he said.
Croplan has one Viptera trait available as well, says Michael Kereluik, product line manager for Winfield United, which includes the Croplan brand. It’s a 3200 heat unit hybrid. He said they are also looking at the Tricepta and Duracade trait packages and expects to have more Viptera hybrids available for 2021.
How was insect pressure this year?
The late, wet, spring threw what was thought to be effective scouting and moth trapping into disarray. It was difficult to find egg masses and it was thought that meant that there was low incidence in southern Ontario, said Harwood.
As the crop matured, there’s been more insect feeding that was expected based on scouting, especially in pockets of southern Ontario.
In the Ottawa Valley and parts of Quebec, it’s been much more of an issue.
He saw some places in the Ottawa Valley where there was close to 100 per cent colonization of plants.
“I was quite amazed at pressure had there this year,” he said.
Greg Good, seeds product lead for corn, soybeans and vegetables with Syngenta says that there’s no doubt the range of the pest expanding.
“We’re getting an understanding of its expanded geographical penetration. It’s more of a mainstream pest than what it was previously,” he says.
There also was a resurgence of corn rootworm this year, especially on sandy soils and where corn was planted after corn.
Freitag said it was so bad for some farmers that they had to spray insecticides as the rootworm were clipping silks from corn ears.
There are highly effective traits to control rootworm and with a lack of pressure farmers may have moved away from using them.
Harwood says it looks like farmers are increasing their purchase of corn with traits to protect against rootworm for next planting season.
Freitag says they’ve seen that sunflowers could be a trap crop for rootworm when planted in a cover crop, so farmers planting corn and cover crops and with rootworm pressure should keep that in mind.
Farmtario contacted nine companies for information on their WBC corn offerings, but not all of them responded by press time.
Updated Nov. 6, 2019 to include more input from corn seed companies.