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Corn: Symptoms in the Field

Author: OMAFRA Staff
Creation Date: 01 March 2002
Last Reviewed: 01 March 2002
Agronomy Guide > Pub 811: Corn > Symptoms In The Field
Excerpt from Agronomy Guide for Field Crops (Chapter 3)
Order OMAFRA Publication 811: Agronomy Guide for Field Crops

Table of Contents

  1. Introduction
  2. Symptoms in the Field - Table 3-27
  3. Updates on Corn: Symptoms In The Field
  4. Related links...

Introduction

Table 3-27. Symptoms in the Field, shows insects and pests that could be causing the symptoms in the field.
Individual descriptions of insects found in corn and recommendations for their control follow.

Table 3-27. Symptoms in the Field

Legend:
X - causing the symptoms
- - not causing the symptoms

Gaps in the Stand
Symptoms Insects and Pests (A to C)
Fall
armyworm		 True
armyworm		 Black
cutworm		 Corn
earworm		 Corn
flea
beetle		 Corn leaf aphid Corn rootworm adult Corn rootworm larva
Seed is fed upon or hollowed out - - - - - - - -
Plants are stunted or wilting - - - - - - - -
Plants are cut off at or below soil level - - X - - - - -
Symptoms Insects and Pests (E to W)
European chafer European corn borer Grasshoppers Potato stem borer Seedcorn beetle Seedcorn maggot Slugs Wireworms
Seed is fed upon or hollowed out - - - - X X X X
Plants are stunted or wilting X - - X - - - X
Plants are cut off at or below soil level - - - X - - - -

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Leaf Tissue Feeding

Symptoms Insects and Pests (A to C)
Fall
armyworm		 True
armyworm		 Black
cutworm		 Corn
earworm		 Corn
flea
beetle		 Corn leaf aphid Corn rootworm adult Corn rootworm larva
Feeding holes are ragged X X X - - - - -
Pinholes or round, symmetrical holes - - - - - - - -
Feeding tracks running parallel to leaf veins on upper surface of leaf - - - - X - - -
Symptoms Insects and Pests (E to W)
European chafer European corn borer Grasshoppers Potato stem borer Seedcorn beetle Seedcorn maggot Slugs Wireworms
Feeding holes are ragged - - - - - - - X
Pinholes or round, symmetrical holes - X - - - - - -
Feeding tracks running parallel to leaf veins on upper surface of leaf - - - - - - - -

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Stalk Damage

Symptoms Insects and Pests (A to C)
Fall
armyworm		 True
armyworm		 Black
cutworm		 Corn
earworm		 Corn
flea
beetle		 Corn leaf aphid Corn rootworm adult Corn rootworm larva
Tunnelling within the stalk - - - - - - - -
Stalk "goosenecked" - - - - - - - X
Symptoms Insects and Pests (E to W)
European chafer European corn borer Grasshoppers Potato stem borer Seedcorn beetle Seedcorn maggot Slugs Wireworms
Tunnelling within the stalk - X - X - - - -
Stalk "goosenecked" - - - - - - - -

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Ear Damage

Symptoms Insects and Pests (A to C) (more)
Fall
armyworm		 True
armyworm		 Black
cutworm		 Corn
earworm		 Corn
flea
beetle		 Corn leaf aphid Corn rootworm adult Corn rootworm larva
Large chunks or kernels missing:
  • entry hole on side of ear and feeding throughout ear
    		•  X - - - - - - -
  • no entry hole into ear and feeding concentrated on ear tip
    		•  - - - X - - - -
    Surface feeding on kernels and/or husk tunnelling - - - - - - - -
    Silks clipped - - - X - - - -
    Ears drop - - - - - - - -
    Symptoms Insects and Pests (E to W) (return)
    European chafer European corn borer Grasshoppers Potato stem borer Seedcorn beetle Seedcorn maggot Slugs Wireworms
    Large chunks or kernels missing:
  • entry hole on side of ear and feeding throughout ear
    		•  - - - - - - - -
  • no entry hole into ear and feeding concentrated on ear tip
    		•  - - - - - - - -
    Surface feeding on kernels and/or husk tunnelling - X - - - - - -
    Silks clipped - - X - - - - -
    Ears drop - X - - - - - -

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    Tassel Damage
    Symptoms Insects and Pests (A to C)
    Fall
    armyworm    		 True
    armyworm    		 Black
    cutworm    		 Corn
    earworm    		 Corn
    flea
    beetle    		 Corn leaf aphid Corn rootworm adult Corn rootworm larva
    Broken tassels - - - - - - - -
    Tassels discoloured or sticky - - - - - X - -
    Tassels are fed on - - - X - - - -
    Symptoms Insects and Pests (E to W)
    European chafer European corn borer Grasshoppers Potato stem borer Seedcorn beetle Seedcorn maggot Slugs Wireworms
    Broken tassels - X - - - - - -
    Tassels discoloured or sticky - - - - - - - -
    Tassels are fed on - - - - - - - -

    Updates on Corn: Symptoms in the Field

    No updates available at this time.

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    Related links...

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