Team discovers how western corn rootworm resists crop rotation

A new study answers a question that has baffled researchers for more than 15 years: how does the western corn rootworm – an insect that thrives on corn but dies on soybeans – persist in fields that alternate between corn and soybeans?

The answer, researchers say, has to do with enzyme production in the rootworm gut.

Their findings are described in a paper in Ecology and Evolution.

Crop rotation declined in the middle of the 20th century as the use of insecticides and fertilizers expanded in the US.

Then in the 1950s and '60s, when some insecticides began to fail, growers again turned to crop rotation to kill off the rootworms that fed on corn.

The method was effective for decades, but by 1995 some growers started seeing rootworm damage even in rotated fields. Today rotation-resistant rootworms are widespread in the Midwest cornbelt, where corn and soybeans dominate the landscape.