A sticky trap monitoring program conducted earlier this month by Monsanto suggests that the western corn rootworm variant may continue to be expanding, posing a potential threat to first-year corn next season.

Monsanto distributed 28,000 Pherocon^® AM sticky traps in early August to growers in parts of five Central Corn Belt states – Iowa, Illinois, Indiana, Ohio and Missouri – where the rootworm variant has been expanding.  Growers participating in the monitoring program, which covered more than 10 million acres, were asked to place the sticky traps in their soybean fields to determine whether the rootworm beetles are present and at what level.

The variant has adapted its reproductive practices by laying its eggs in soybean fields in order to survive field rotations between corn and soybeans.  The variant eggs hatch during the spring, after the field has been rotated back to corn, resulting in larval feeding in first-year corn.

"Results from this grower data shows that the western corn rootworm beetle was trapped in almost all counties where the sticky traps were sent and placed in soybean fields by growers," said Dave Rhylander, Director of Traits for Monsanto. "This would suggest that the rootworm variant may be continuing to expand its geography, which could result in greater rootworm pressure when soybean fields are rotated back to corn in 2006.  We will continue to work with university academics to validate these observations."

Growers in these locations, Rhylander said, should:

• Inspect their corn fields this year and look for the presence of corn rootworm beetles.  Look for lodged plants or dig corn plants and inspect the roots for feeding.
   

• Continue to monitor the movement of the rootworm variant in their area.  Talk to other growers, local extension entomologists, retailers and seed dealers, to see if other farmers have reported lodged corn or rootworm feeding.
   

• Consider using technology that will control rootworm in first year corn, such as YieldGard^® Plus, the first corn technology to deliver whole-season, in-plant protection against European and southwestern corn borers and effective and consistent protection against western and northern corn rootworms.

• Monitor soybeans fields in 2006 by utilizing sticky traps.  Growers interested in obtaining sticky traps can call 1-866-ROOTDIG by November 15, 2005 to be put on a list to receive the traps.

Rhylander said that in several counties, the number of beetles exceeded the economic threshold for control of this pest. "We are currently confirming this information with universities, since this would indicate increased pressure of this pest above what has historically been measured in these areas," Rhylander said.  "Growers in the counties where the number of variant western corn rootworms were at or above threshold should be on the lookout for signs of corn rootworm damage and they should potentially consider managing rootworms in their fields in 2006 if they verify, based on the criteria outlined above, that they have a potential problem."

First sighted in east-central Illinois in the early 1990s, the western corn rootworm variant has continued to spread throughout the Midwest in recent years.  

The sticky traps were distributed to about 3,600 growers in portions of Iowa, Illinois, Indiana, Ohio and Missouri.  Each grower was asked to put out six traps, evenly distributed throughout their soybean fields, and leave them in place for seven days during peak flight.

The beetles are drawn to the sticky traps by their yellow color and then are caught on a sticky surface. Growers were asked to then remove the traps, count the number of rootworm beetles embedded on the sticky surface and mail in a postcard with the results. 

Test results will be communicated to all participants in the testing program to assist with their insect management planning for 2006.  "Our goal is to raise grower awareness about the expansion of the corn rootworm variant so that producers in high-risk areas can consider appropriate management options to protect their first-year corn next season," explains John Jansen, Corn Traits Marketing Manager for Monsanto.  “Without the participation of these growers, this information may not have been available through other sources. Monsanto is proud to recognize these growers for their commitment to the greater good of agriculture.”

Growers of YieldGard Plus Corn must always follow grain marketing and insect resistance management requirements and must also follow pesticide label directions.
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