In early October, a group of Extension entomologists from the Great Lakes region sent an open letter to the seed industry about the efficacy of Cry1F (Herculex 1, TC1507) trait on western bean cutworm. The entomologists strongly urged seed companies to remove the designation of “control” for this pest with regard to this toxin.
In the letter, the scientists explain the evolution of the western bean cutworm in the United States and how the Cry1F trait was put to the test. They wrote:
The rapid eastward range expansion of WBC across the central Corn Belt into the Great Lakes Region resulted in a dramatic increase in the number of WBC-infested acres in a short time period. This created a large-scale ‘efficacy test’ of Cry1F hybrids to … ‘provide highly efficacious control of key Lepidopteran pests,’ ‘reduce the use of more toxic chemical insecticides’ and ‘reduce levels of mycotoxin in corn.’ In all these regards, Cry1F has failed in our states. This season in particular, the level of larval infestation and damage is troubling in both single and pyramided Refuge-in-a-Bag hybrids from multiple seed companies.
Wherever Cry1F is challenged by WBC, it fails to provide observable benefit to producers. We have collectively fielded dozens of phone calls and emails, and visited numerous fields; we know that our agribusiness contacts and seed industry agronomists have responded to many more, and corn acres were sprayed with both insecticides and fungicides (most too late and with little hope of benefit). People are frustrated and angry and, more importantly, yield was lost. Growers purchased Cry1F hybrids with the understanding that the trait provides ‘control,’ thus negating the need to scout for egg masses or larvae in those fields. When the visible manifestations of damage became apparent late in the season, such as the intense ear-feeding we witnessed, it was far too late for rescue treatments.
Through their letter, the university entomologists asked companies to acknowledge what is happening with regard to western bean cutworm and reclassify Cry1F in hybrid fact sheets, technical use agreements and other education materials — before grower make their 2017 seed choices.
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Signing entomologists include: Chris DiFonzo, Michigan State University; Christian Krupke, Purdue University; Andy Michel and Kelley Tilmon, The Ohio State University; Elson Shields, Cornell Universit; and John Tooker, Pennsylvania State University.
To read the letter in its entirety, visit the Purdue University Pest & Crop Newsletter.
