University trials conducted throughout the U.S. Corn Belt this past summer have shown that Herculex® RW rootworm protection (HXRW) is an extremely effective choice for corn rootworm control, surpassing even conventional soil-applied granular insecticides.

In 10 university trials, corn hybrids containing the HXRW trait kept corn rootworm at levels that prevented yield loss, with no root pruning and only slight scarring and root-tip feeding. Products tested in the trials were Pioneer® brand hybrids with the HXRW trait.

HXRW, with protection built into the seed, provided much better control than conventional insecticides applied at planting, according to trial results. This early protection helps plants get off to a fast, healthy start.

"Herculex provides protection when growers need it, which is from planting through the first week or two of July," says Larry Bledsoe, entomology research assistant at Purdue University. The University of Illinois, Iowa State University and other leading schools also participated in the research. This research evaluated only early-season protection, but other field results strongly suggest excellent season-long protection as well.

The trials were designed to evaluate the ability of the HXRW trait to protect corn from root feeding damage by rootworm larvae. Each trial compared an untreated check with a hybrid with the HXRW trait and the same hybrid protected with a granular, soil-applied insecticide.

Plots were evaluated using a node injury score showing the average number of nodes, or groups, of roots pruned by rootworms. Because there are three nodes of primary roots on corn plants, the scale ranges from 0 to 3.0, with yields losses usually beginning at scores of 0.5 to 1.0. HXRW performed especially well in three key states.

"Locations in Iowa, Illinois and Indiana experienced very high corn rootworm (CRW) pressure and clearly demonstrated the ability of the HXRW trait to protect corn roots from corn rootworm," says Tom Doerge, agronomy research scientist for Pioneer.

In Iowa, the score for the HXRW trait was 0.02, compared with 0.32 for the granular insecticide and 1.73 for the check.

In Illinois, HXRW scored 0.07, the insecticide 0.23 and the check 2.08.

In Indiana, HXRW had a score of 0.09, compared with 0.48 for the insecticide and 2.17 for the check.

"Damage in the untreated controls had an average node injury score of 2.17 nodes pruned," says Doerge. "This means that just over two-thirds of the roots of the unprotected plants were severely pruned. In contrast, the root injury on hybrids containing the HXRW trait averaged 0.09. That score indicated no root pruning and only slight scarring and root-tip feeding."

HXRW also performed well at seven other sites where rootworm pressure was less severe.

"HXRW consistently provided more root protection than the soil-applied insecticide," he says. The HXRW trait demonstrated excellent control of the three main species of corn rootworm.

HXRW is a Bt trait that protects against western, northern and Mexican corn rootworm. "Because protection is in the seed, it gives growers an effective alternative to seed- or soil-applied insecticides," says Doerge.

Pioneer reminds growers of the importance of good stewardship practices, including the use of a field refuge, to keep the HXRW trait effective.

Bledsoe encourages growers to see how the technology will perform best under their own management practices.

"As with any new technology, don't overrepresent any one hybrid on your farm," he says. "Start out slowly and see how this technology fits into your total seed package, just as you would with any hybrid."

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.

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Herculex RW rootworm protection technology by Dow AgroSciences and Pioneer Hi-Bred.
®Herculex is a registered trademark of Dow AgroSciences LLC.