In 2018, farmers in Nova Scotia, Canada, noticed a pest they hadn’t seen in a long time — the European corn borer.
The pest was introduced to the United States in 1917 and spread to most major corn-growing regions by the 1940s. Coined “the billion-dollar pest,” the European corn borer caused yield loss by burrowing into cornstalks and feeding on them until the introduction of Bt corn in 1996.
The main indicator of the borer is a horizontal line of shot holes in the corn leaves. The discovery in Nova Scotia led researchers to investigate throughout Canada, where they continued to find the same Cry1F resistance in the borer as they found in Nova Scotia. Cry1F is the crystalline protein used in Bt corn that keeps larvae at bay.
In the years from 2018–2023, researchers started to make collections all across Canada and they were finding European corn borer resistance to Cry1F toxins all across the board.
-NAFB