No. 19 Article 2/July 29, 2005

Corn Rootworm "Digs" Completed in DeKalb and Monmouth

On July 25 and 26, we completed our corn rootworm "digs" (about 1,600 roots at each location) in Monmouth and DeKalb, respectively. In addition to these experiments, crop systems and IPM Extension educators are continuing their cooperation in an on-farm survey of first-year corn rootworm larval injury. By mid-August, we intend to share the preliminary results of our root evaluations from multiple projects this summer. Because of the very dry conditions at some of our sites, such as Monmouth, product performance will be significantly challenged. At each site, the level of root damage was severe across many treatments. However, overall plant height and root regeneration appeared more negatively affected at the Monmouth experiment.

Darren Bakken, a graduate research assistant with our IPM program in Crop Sciences, has established an interesting experiment at three locations (DeKalb, Monmouth, and Urbana) that includes three split treatments: YieldGard hybrid, the isoline treated with Poncho 1250, and the isoline without any insecticide. The whole-plot treatments consist of five different nitrogen rates: 0, 60, 120, 180, and 240 pounds per acre. The experiment at each location has been established on corn following a trap crop of corn as well as soybeans. Because of the drought conditions and severe corn rootworm injury that have developed this summer, we have witnessed striking contrasts among the various treatments. In general, the vigor (color, height) of plants in corn following soybeans appears to be much better. The height of YieldGard plants in our experiments also is considerably greater than the other treatments. This has been a common observation this summer. We look forward to Darren's full assessment of his experiment later this year

Brown grass alleys at Monmouth Research and Education Center, July 25, 2005.

Drought-stressed plants at Monmouth Research and Education Center, July 25, 2005.

Severe corn rootworm damage, DeKalb Research and Education Center, July 26, 2005.

Root-digging crew, DeKalb Research and Education Center, July 26, 2005.

--Mike Gray

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