No. 16 Article 3/July 11, 2008

Black Cutworms in Late-Planted Corn and Soybeans

As we have suspected, black cutworms have continued to pose a threat to late-planted corn and, as we learned recently, late-planted soybeans. We typically focus on black cutworms only early in the season, when corn is in stages VE through V6 or so. But 2008 has been unlike most other years, so the summer generation of black cutworms in Illinois has caused some problems in fields that were planted late because of this spring's wet conditions. Robert Bellm, University of Illinois Extension crop systems educator in Edwardsville, shared some reports from Bond, Madison, and Montgomery counties, where many fields were being treated with insecticides to control black cutworms in fields that had been planted between June 10 and 20.

Although we usually don't worry too much about black cutworm injury to seedling soybeans because of the initial high plant populations, Dan Schaefer of Illini FS in Tolono reported on a field where the plant population of soybeans was reduced by as much as 50% in some places. Replanting was warranted in some large areas of the field, and an insecticide was applied to protect the new growth.

I write about this only to remind people that anything seems to be possible with insects this year, so observation should be intensified accordingly. Soon enough we'll be into the time for mid- to late-season insect pests to take over, but in the meantime, don't disregard the early-season insects "coming back for more."--Kevin Steffey

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