We’ve observed many instances of heavy corn earworm infestations over the last few years throughout NuTech Seed’s footprint.  Corn earworm are a migratory pest that overwinter in warmer areas in the southern states.  Overwintering mortality rates may likely be less this year because of the mild winter.  Corn earworm are difficult to manage with traditional chemical control methods, please visit the link to NuTech’s Agronomy Library for more information on corn earworm https://nutechseed.com/wp-content/uploads/2019/07/Corn_Pests_Corn-Earworm_NuTech.pdf.

At a recent Crop Advantage Series meeting in Coralville, IA, Erin Hodgson, Extension Entomologist Specialist at Iowa State University, mentioned that USDA entomologists confirmed corn earworm resistance to multiple Bt Cry proteins.

Our Optimum AcreMax Leptra (AML) trait is a pyramid stack of Bt traits and is still effective on corn earworm.  It also controls western bean cutworm and stalk borer.

AML traited hybrids carry a slight premium in price compared to AcreMax® traited hybrids.  However, the difference in price is easily recovered in the event of a corn earworm infestation.  A few reasons are:

  • Physical loss of kernels from earworm feeding
  • Damaged kernels develop mold quickly and increase risk of mycotoxins
  • Challenges of storing damaged grain

With 30,000 ears/acre and 126,000 kernels/bushel, it only takes 4.2 kernels/ear to equal a bushel.  Kernels at the ear tip are usually smaller, hence the reason I used the small kernel size in this example.  To put that into perspective, 126,000 kernels/bushel equals 2,250 kernels/pound, the equivalent of a 35.5 lb 80K unit of seed corn.

Usually, damage from corn earworm affects larger kernels which will take even less kernels/ear to equal a bushel.

The addition on AML hybrids into the package can be a great return on investment, especially when the hybrid deserves to be on the farm whether it has AML or not.  Hint, Hint…68B3AML.

Photos by Chris Adams, NuTech Seed, LLC

AML – Optimum® AcreMax® Leptra® products with AVBL, YGCB, HX1, LL, RR2. Contains a single-bag integrated refuge solution for above-ground insects. In EPA-designated cotton growing countries, a 20% separate corn borere refuge must be planted with Optimum AcreMax Leptra products.

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