Pioneer Hi-Bred International, Inc., has joined the effort to track the eastward movement of western bean cutworm (WBC), a destructive pest that can reduce corn yields by as much as 30 percent to 40 percent. Pioneer agronomists and sales representatives in Iowa, Illinois, Missouri, Minnesota and Wisconsin will place and monitor more than 200 WBC pheromone traps.

Extension entomologists at Iowa State University, University of Missouri, University of Wisconsin, Purdue University and the University of Illinois also will be tracking the movement of this insect.

For the past three years, Iowa State University (ISU) Department of Entomology has led the effort to coordinate cooperators to assist in scouting and identifying the emergence patterns of WBC. Growers can access the latest WBC data for all states by logging on to www.ent.iastate.edu/trap/westernbeancutworm. The site is a tool for growers to assess the WBC infestation, damage and peak hatching time in their area.

“Each year, we’re finding that WBC continues to spread farther east from the Great Plains, which emphasizes the need for scouting,” says Brent Wilson, Pioneer technical information manager located in Iowa. Pioneer joined ISU in the effort to monitor WBC during the 2004 growing season.

In 2005, pheromone traps confirmed movement of WBC into the northern half of Illinois and many counties in Wisconsin. Before 2005, the insect was found in Iowa, southern Minnesota, northern Missouri, Colorado, South Dakota, Nebraska, western Kansas and the panhandles of Texas and Oklahoma.

“We found that monitoring the movement of this insect is a real benefit to our customers not only during the growing season, but when they make their seed-purchasing decisions,” adds Wilson.

Historically, management of WBC has been limited to careful scouting and timely application of insecticides. Growers now have access to in-plant control of WBC with the Herculex® I and Herculex XTRA insect protection traits. Herculex XTRA contains both the Herculex I trait and the Herculex RW trait for corn rootworm control.

In addition to guarding against western bean cutworm, the Herculex I gene protects the corn plant against European and southwestern corn borer, black cutworm, fall armyworm, corn earworm, sugarcane borer, southern cornstalk borer and lesser cornstalk borer. In addition to those insects, Herculex XTRA also protects against western, northern and Mexican corn rootworms. Herculex XTRA guards against a broader range of above- and below-ground insects in corn than any other in-seed product on the market.

The life of a WBC
Adult WBC moths emerge in mid- to late July, mate and begin laying eggs immediately. WBC moths lay eggs in masses from five to 200. Eggs will turn purple by the fifth day of development and hatch as larvae one or two days later.

Young WBC larvae feed on tassels and silks, but eventually tunnel through the silk channel to reach the developing kernels. Direct yield loss occurs as larvae consume all or parts of developing kernels. Partially consumed kernels may be attacked further by ear molds or secondary insect feeders that enter the ear through the WBC feeding channel.

“Once these larvae enter the ear tip, control is nearly impossible,” says Wilson. “If farmers choose to fight WBC with insecticide, peak hatching must be identified and immediate spraying must follow.”

Wilson adds that if an insecticide is needed, the application should be timed so 90 percent to 95 percent tassel emergence has occurred. If the tassels already have emerged, the application should be timed when 70 percent to 90 percent of the larvae have hatched.

For more information about western bean cutworm tracking or the Herculex family of insect protection technology, contact your local Pioneer representative.

Pioneer Hi-Bred International, Inc., a subsidiary of DuPont, is the world’s leading source of customized solutions for farmers, livestock producers and grain and oilseed processors. With headquarters in Des Moines, Iowa, Pioneer provides access to advanced plant genetics, crop protection solutions and quality crop systems to customers in nearly 70 countries. DuPont is a science company. Founded in 1802, DuPont puts science to work by creating sustainable solutions essential to a better, safer, healthier life for people everywhere. Operating in more than 70 countries, DuPont offers a wide range of innovative products and services for markets including agriculture, nutrition, electronics, communications, safety and protection, home and construction, transportation and apparel.