Redlegged and differential grasshoppers have defoliated border rows of cornfields in Crawford and Carroll counties in west central Iowa. In some fields the damage started during July and grasshoppers ate everything except the stalk, ear, and leaf midribs, causing the plants to die by late August. Complete defoliation extended five to seven rows into the field in some areas. Grain yields will be reduced in these rows but little could have been done to prevent the damage once the grasshoppers moved into the tall corn. Insecticides would have been the only option for control but getting spray equipment into tasseling-stage corn to spray a few border rows would not have been practical. Where significant grasshopper damage occurs, field edges should be scouted during June next year for grasshopper nymphs as they the feed on grasses and weeds. Control tactics possibly could be implemented before the grasshoppers move into the corn.
|Field corn killed by grasshoppers in early September 2001 near Denison, Iowa.|
This article originally appeared on pages 180-181 of the IC-486(22) -- September 17, 2001 issue.