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OMAFRA: Corn rootworm resistance to Bt hybrids likely spread to new counties

In the most recent crop report put out by the Ontario Ministry of Agriculture, Food and Rural Affairs’ (OMAFRA) field crop team, cases of likely corn rootworm resistance to Bt rootworm (Bt-RW) hybrids have cropped up in fields of continuous corn (three or more years).

According to the report, unexpected damage on Bt-RW hybrids – hybrids with below-ground protection – has been found in several fields and new counties in August. The damage includes significant stunting, root clipping, goose-necking, silk clipping and abundant rootworm adult populations mating and feeding – all of which are likely signs of rootworm resistance to Bt-RW proteins.

The damage caused by corn rootworm to corn crops results in yield and quality loss. By continuing to grow corn on corn and solely relying on Bt rootworm hybrids as the rootworm management tool, the resistance issue remains unmanaged, while also producing less and lower quality feed for livestock.

The OMAFRA Field Crop News website offers tips and strategies for reducing rootworm populations and alternative management options; most require adopting a long-term view and enduring short-term hurdles. |READ MORE