Hyper-linked corn seedling insect diagnostic guide

John Obermeyer and Larry Bledsoe
Purdue Extension Entomology

The following diagnostic guide has been developed to facilitate the field problem solving process for corn early in the season. Corn symptoms from insect damage are listed below. Possible causes are listed for each symptom; insect names are hyper-linked and clicking on it will link to a page for further information about the pest, plant damage, scouting methods, and links to Purdue's conventional management guidelines.

Happy and accurate scouting!

	General Appearance: Plants wilting Symptom: Upper leaves roll; and affected plants appear dull, and may be stunted; plants may die. Cause(s): Black cutworm White grubs Wireworms Grape colaspis grub Corn root aphid
	General Appearance: Plants discolored Symptom: Purpling or reddening of leaves from tip back; initially lower leaves affected; leaf tips may later turn dark brown and die. Cause(s): White grubs Grape colaspis grub
	General Appearance: Plants discolored, malformed, and/or stunted Symptom: Yellow elongated areas on leaves and/or yellow halo around holes; upper leaves may roll and twist, plants may show excessive tillering, stunting, and/or deformity Cause: Brown stink bug
	OR
	General Appearance: Plants discolored, malformed, and/or stunted Symptom: Plants bent or twisted; stunted; irregular to round rows of holes in unfolded leaves Cause(s): Stalk borer Billbugs Brown stink bug
	General Appearance: Plant tissue removed Symptom: Whole plants cut off at ground level Cause(s): Black cutworm Sod webworms Variegated cutworm
	OR
	General Appearance: Plant tissue removed Symptom: Leaves entirely eaten off or large chunks of leaf tissue removed Cause(s): Armyworm Grasshoppers
	OR
	General Appearance: Plant tissue removed Symptom: Ragged holes in the leaves Cause(s): Black cutworm Slugs Variegated cutworm Stalk borer Armyworm Southern corn leaf beetle
	OR
	General Appearance: Plant tissue removed Symptom: Rows of circular to elliptical holes across leaves Cause(s): Billbug Stalk borer Brown stink bug
	OR
	General Appearance: Plant tissue removed Symptom: Irregular gray to brown narrow lines or "tracks" scratched from the top layer of leaf tissue; heavily infested leaves may appear gray in color, shrivel, and die Cause: Corn flea beetle

Return to April 15, 2004 issue New Agriculture Network.

Funding to initiate this network was provided by the American Farmland Trust and EPA Region 5.
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Contact webmaster. Updated 04/15/04