If there’s a corn insect that has the inside track to Pest of the Year, it’s got to be the western bean cutworm (WBCW).

Once considered a pest of the Plains, WBCW used to make its living raiding eastern Nebraska cornfields, then withdrawing back to its home of dry beans and sandy soils in western Nebraska. While WBCW has been present in Iowa since the turn of the decade, it often didn’t show up at levels that caused economic damage. That changed this summer with outbreak levels of WBCW throughout much of the state.

For those corn growers who chose either the in-plant trait Herculex® I Insect Protection or Herculex XTRA Insect Protection over YieldGard, they were protected against WBCW. Other producers were left scrambling for a rescue spray to stop the outbreak.

“Many producers who grew corn with the YieldGard trait saw significant damage,” says Kelly Montgomery, product development agronomist for Dow AgroSciences in Iowa. “They did so believing western bean cutworm would not be a problem and, needless to say, they weren’t thrilled with having to spend the extra money on insecticide to control western bean cutworm.

“In many cases, the larvae had already made their way into the silks before being discovered, which meant it was too late to control them and the grower was going to have to live with whatever damage occurred.”

The western bean cutworm moves east

The Western Bean Cutworm Monitoring Network* paints a vivid picture of the level of infestation that occurred this past summer in Iowa. Eighty of the state’s 99 counties had traps set in place to monitor WBCW moth flights. As of Aug. 4, 63 counties had seen moth captures at levels of greater than 100 per week. Of those, 38 had seen moth captures of greater than 500 per week.

Now, WBCW appears to have its sight set on cornfields east of the Mississippi River. Seven counties in northwestern Illinois; Vernon and Crawford counties along the Mississippi River in Wisconsin; and Newton County in northwestern Indiana captured moths at levels of greater than 100 per week. Additionally, moths were captured for the first time in Michigan and Ohio during 2006.

“The outbreak in Iowa and the high levels of western bean cutworm in northwest Illinois really made it evident that western bean cutworm is a game-changing pest,” says Lyndall Dallas, product development agronomist for Dow AgroSciences in Illinois. “Growers throughout much of the Corn Belt now have to factor western bean cutworm into their management plans.

“Based on the activity of western bean cutworm this year and its continued eastward movement, it’s pretty safe to say that this is a pest that’s here to stay. Growers need to determine their tolerance for this pest.”

Dallas says that even growers who have not experienced economic damage from WBCW are probably going to want the peace-of-mind protection from WBCW that the Herculex family of traits provides.

“For that peace of mind, growers simply should choose a hybrid with Herculex I  or Herculex XTRA Insect Protection,” Dallas adds.

To learn more about the Herculex Insect Protection family of in-plant traits, see your local seed corn dealer or visit www.herculex.net.

* www.ent.iastate.edu/trap/westernbeancutworm/node/11006

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