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European Corn Borer Still Lurks

Thirty years ago, a summertime fuel stop often included an extensive squeegee session to wipe the remains of European corn borer (ECB) moths from a vehicle’s windshield. 

Due to Bt traits that enable corn plants to resist ECB, that’s now seldom the case. That may prompt you to plant corn hybrids without these traits in order to cut costs. 

Be careful. 

Planting a hybrid without ECB protection can slice corn yields if corn borers infest a field. Losses result from feeding at various stages of plant growth, as ECB disrupts nutrient and water flow in stalks by burrowing into them. 

Good news exists. 

Ken Ostlie, University of Minnesota Extension entomologist, doesn’t see ECB soon making a large comeback. ECB populations have massively decreased since the advent of ECB-resistant traits in the mid-1990s. 

“I have seen enough fields over the past two years to know that potential exists,” he says. “For the first time in 15 years, I have been able to show graduate students what a corn borer infestation looks like in a field.”

For 2019, though, the odds are in favor of farmers who forego use of an ECB-resistant trait. 

“With ECB populations low, there is potential if you are a gambling person to reduce the use of Bt traits,” says Ostlie. 

This can appeal to farmers trying to cinch up lower seed costs for 2019 since prices are often lower for conventional hybrids vs. ones containing an ECB-resistant trait. 

Farmers Business Network, for example, offered conventional corn seed for 2019 at $99 per bag on a national basis through its F2F Genetics Network, says Ron Wulfkuhle, FBN head of seed who leads the F2F Genetics Network. This compares to conventional genetics priced at around $160 to $165 per bag (national average), he says. 

Scout and Spray

This approach, though, requires a scout-and-spray ECB management plan, Ostlie says. Farmers who have been planting ECB-resistant corn will feel like they’re morphing back to the early 1990s. 

“It will require visiting fields over four to six weeks,” says Ostlie. In Minnesota, scouting windows occur over summer infestation waves that include: 

  • First-generation infestations. In Minnesota, these are normally in late June to early July. ECB larvae targets the whorl of early-planted corn in these infestations.
  • Univoltine generations. This generation occurs in late July to early August in Minnesota in pretassel corn. 
  • Second-generation infestations occur in pollinating corn during mid- to late August in Minnesota. It often can overlap with a univoltine generation. 

“The easiest generation to scout for is the first generation,” says Ostlie. 

Still, scouting is advised for all generations, as they can inflict damage by tunneling into stalks. As an example, Minnesota thresholds based on current economics vary by generation. They are as follows.

  •    First generation: .58 larvae per plant
  •    Univoltine generation: .47 larvae per plant
  •    Second generation: 1.15 larvae per plant 

Foliar insecticide control costs around $15 per acre, plus the time spent scouting. 

“You will not get the 99.9% control that occurs with Bt traits,” says Ostlie. 

At best, foliar insecticides give the following control.

  •    75% control of first-generation ECB
  •    65% control of the univoltine generation
  •    40% to 45% control for second-generation ECB

Focus on ROI

Up front, it can be less expensive to go with conventional corn or one that doesn’t have an ECB-resistant trait, says Clayton Becker, who heads the Golden Harvest west commercial unit. Still, he advises to consider return on investment when selecting seed. 

“It can be a dangerous cycle just to solely go with cheaper seed,” Becker says. “Genetics and product placement can better help build your bottom line. Traits still have a tremendous amount of value that still translates to a good return on investment.”

Product placement also can impact performance. “We know that hybrids can react differently to factors like fertility or conventional tillage, or with or without cover crops,” Becker says.

Access to digital technologies that aid seed selection can also play a role in bettering return on investment, says Quinn Showalter, who heads sales for NK. 

“One of the things we hear about, particularly from larger farms, is they use several digital platforms to manage their businesses and that they want to unlock the power of data and analytics. One of the things that will evolve over the next few years is the connection of all these various digital tools to better make decisions.”  

Soybean Seed Outlook 

Wet conditions in many areas this fall led to soybean sprouting in pods. Maladies like this could compromise soybean seed quality for 2019. Quinn Showalter, head of sales for NK, advises you to check seed labels for germination and other seed-quality factors.

Soybean germination rates that are normally greater than 90% could sink below that in some seed lots, says Showalter. 

“This could be a year when soybean quality could be quite variable from the companies you buy from,” he says.

As with corn, price looms large in soybean seed purchase decisions. Still, remember that new genetics often are packed with increased yield potential, says Showalter. 

“New genetics are always going to be a premium price because of the improvement in genetic gain they deliver and yield improvement over older genetics,” says Showalter.

Study, Study, Study

Time spent studying seed selection is well worth it, says Mark Licht, Iowa State University Extension agronomist. 

“The best way to know the performance of a corn hybrid or a soybean variety is to look at as much data as you can, whether it’s from a university, a state testing program, FIRST trials, or through your local co-op or seed dealer,” says Licht. “Reviewing as much data as possible, especially if it’s geographically close, gives you the best idea of how varieties and hybrids will perform.” 

By Gil Gullickson

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