A new corn rootworm trait that is in the late stages of regulatory approval has demonstrated excellent control, consistency and yield results in extensive university and Syngenta testing.  Event MIR604*, which Syngenta seeks to commercialize under its Agrisure™ brand of traits, has shown an average 32 bushel-per-acre yield advantage in rootworm-infested fields and, in Syngenta studies, no yield drag compared to the hybrid isoline.

MIR604 is being reviewed by the Department of Agriculture, the Food and Drug Administration (FDA) and in experimental trials under the Environmental Protection Agency (EPA).  If it is approved, Syngenta hopes to market MIR604 as Agrisure RW, individually and in stacks, through elite hybrids of its Garst®, Golden Harvest® and NK® brands to growers in the U.S. for planting in the 2007 season.  Syngenta already markets Agrisure GT (glyphosate tolerance), Agrisure CB/LL (season-long corn borer control with Liberty® herbicide tolerance) and Agrisure GT/CB/LL (stacked traits).

“MIR604, the Agrisure rootworm event, has exceeded our expectations in rigorous testing conducted throughout the Midwest Corn Belt,” says Jack Bernens, head, Agrisure traits. “In addition to demonstrating effective, consistent protection from corn rootworm, it has been placed in leading Syngenta genetics utilizing an industry-leading trait conversion process that will ensure hybrids with this trait will reach their full yield potential.”

Offering excellent built-in control of corn rootworm, MIR604 is a modified full length Cry3Aa gene from Bacillus thuringiensis (Bt).  The modification extends the activity of this gene to Mexican, northern and western corn rootworms.  MIR604 controls newly hatched rootworms through the first larval instar as they begin to feed on corn roots.  The larvae are eliminated as soon as they consume the unique Bt protein in the roots.

More than 60 trials over a three-year period were conducted across the Corn Belt by nine Midwestern universities and Syngenta(1).  In trials with economic pest pressure, hybrids with MIR604provided an average root rating of 0.22 (on a 0-3 Node-Injury Scale, with 0.01 representing no feeding damage and 3.00 being the highest level of root damage), well below the industry-accepted economic threshold of 0.75. Conventional check plots showed an average root rating of 1.51 over the same time period.  The rootworm event also provided more effective control when compared to standard insecticide treatments.

MIR604 had an 89 percent consistency of control averaged over the same trials and under varying weather conditions.  Consistency is a measure of the frequency of when the individual roots average equal to or less than 0.5.  In comparison, untreated control plots averaged 33 percent consistency.

In areas of high insect pressure, MIR604 averaged a 0.37 in root rating and 79 percent consistency, while the untreated plots averaged a 2.3 rating and 12 percent consistency.

University entomologists who have conducted research on the new trait in their respective state over the past three years are encouraged at the results.  In Kansas, for example, trials demonstrated outstanding control under extreme rootworm pressure.  ”We’ve had a damage rating of 2.00 in the untreated plots and virtually no damage in the MIR604 fields,” says Gerald Wilde, Kansas State University extension entomologist. “The new trait performed very well, even under severe pressure.”

Further east in Indiana, Larry Bledsoe, entomologist at Purdue University, noted that trials in 2005 were subjected to heavy rootworm pressure and a prolonged period of drought.  “The MIR604 plots performed well, while the conditions in the check plots allowed rootworms to feed faster than the roots were growing,” Bledsoe noted.

Bernens notes that, if it is approved, MIR604 would be placed in elite genetics utilizing an industry-leading trait conversion process that allows the hybrids to reach their full yield potential.  The Syngenta system of marker-assisted breeding helps ensure proper conversion and maintains the efficacy of the trait.

“Syngenta has taken the time to find the right way to convert this gene to maximize the potential of the rootworm trait and place it in the highest quality hybrids,” Bernens says.  “This will also allow growers to reap the full benefits of the trait – unparalleled control of rootworms and maximum yield potential.”

MIR604 is one of many new products in development through Syngenta biotech research and development.  Agrisure GT (glyphosate-tolerant corn) and Agrisure CB (protection against corn borers) and the stack of Agrisure GT/CB were the first Syngenta traits to be introduced commercially in 2005.  Other innovative stacks will follow. 

For more information, please visit Agrisuretraits.com. 

* MIR604, the corn rootworm event, is not currently registered for sale or use in the United States and is therefore not being offered for sale. This news release does not constitute an offer for sale. This product will not be available for sale until the EPA has approved registration and all necessary authorizations have been granted.

Syngenta is a world-leading agribusiness committed to sustainable agriculture through innovative research and technology. The company is a leader in crop protection, and ranks third in the high-value commercial seeds market. Sales in 2005 were approximately $8.1 billion. Syngenta employs some 19,000 people in over 90 countries. Syngenta is listed on the Swiss stock exchange (SYNN) and in New York (SYT). Further information is available at www.syngenta.com.

(1) J.D. Oleson et al., 2005

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