SmartStax standing strong despite heavy corn rootworm pressure

Drought conditions coupled with heavy corn rootworm pressure put many U.S. cornfields under stress this season. However, midseason on-farm root digs showed that Dow AgroSciences SmartStax was providing great protection from corn rootworm on some farms, resulting in strong roots and overall healthier plants.

"We know there are many variables during the season that growers can't control. But as these growers saw this season, with SmartStax, damage from corn rootworm isn't one of them," says Cole Hansen, traits marketing manager for Dow AgroSciences.

Mid-July root digs in Kansas and South Dakota fields planted with SmartStax corn showed how well the SmartStax trait combination stands up to heavy corn rootworm pressure.

"A customer in western Kansas saw several lodged corn plants in his field. After digging up plants in different parts of the field and using ELISA strips to verify the trait package of each plant, we concluded that the refuge plants had severely damaged roots, while the SmartStax traited plants showed minimal feeding damage," says Doug Heatwole, customer agronomist for Mycogen Seeds.

ELISA (enzyme-linked immunosorbent assay) strips test for the presence of the specific proteins produced by SmartStax� in the plant. These tests allowed Heatwole to verify the refuge plants in the field and compare them with the SmartStax plants.

Under the heavy rootworm pressure, the refuge plants had a rating of 2.5 on the Iowa State University node injury scale of 0 to 3. At a rating of 0.25, yield loss can occur; at 1.0, lodging is possible. A rating of 2.5 means 2 1/2 nodes were consumed and significant yield loss is likely. However, the average rating for the SmartStax plants was 0.015, indicating minimal feeding scars to the roots and excellent protection against high rootworm pressure.