The Sharp Edge: Nematodes fight back against corn rootworm resistance

Tyler Cronin. Cronin Family Farms.

Transgenic traits that defend corn plants against against damaging corn rootwoom have been around since 2003. But in recent years, farmers have seen growing resistance to these traits and researchers and seed companies are working to preserve the effectiveness of the technology while also develop new ways to combat the yield-robbing pest. One of those alternatives is soil nematodes. Growing research shows they pack a punch and can knockout resistant rootworms.

On this episode of The Sharp Edge, Maizex agronomist Greg Stewart visits with Tyler Cronin at Cronin Family Farms in Molesworth, Ont. Cronin and his family run a hog operation that includes 5,000 sows and 800 acres of continuous corn.

Cronin is concerned about increasing corn rootworm resistance and is taking steps to manage the growing threat. Extending the rotation, however, to include wheat and soybeans to reduce potential resistance is not a viable option for his family, and most livestock farmers. (Story continues after the video.)

The Cronins do see potential in using soil nematodes to defend their corn crop and are now working with Stewart and University of Guelph research scientist Jocelyn Smith to evaluate this defence on their farm. In the video, Smith shares how Cornell University researcher Elson Shields identified the potential for nematodes to deliver rootworm control. Tens of thousands of acres of corn in New York state have now been inoculated with nematodes and in these fields researchers are seeing rootworm injury reduction of 50 to 90 percent.

Stewart also describes how the nematodes were applied to test plots on the Cronin farm and will be compared to hybrids carrying rootworm transgenic traits as well as corn treated with insecticide. He and Smith discuss how practical it will be for growers to apply nematodes on their farms and what role the roundworms can play in the fight against corn rootworm resistance.

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