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Thursday, August 12, 2021

Early Season Corn Insect Pests, VE to V8

cutworm on corn
Early Season Corn Pests, VE To V8
Corn Growth Stage
   VE       V2       V4       V6       V8       V10       V12       VT       R1   
Below-ground Insect Pests
Seedcorn Maggot
Seedcorn Beetle
White Grubs
Wire Worm
Corn Rootworm Larvae
Above-Ground Insect Pests
Sod Webworm
Grape Colaspis
Black, Dingy, Clayback Cutworms
Chinch Bug
Billbug
Common Stalk Borer
1st Generation European Corn Borer
Above-Ground Non-Insect Pests
Millipedes
Slugs

Below-Ground

When searching for below-ground pests, a small garden trowel or pocketknife is a handy tool to use. Early season insects can be found attacking the seed (seedcorn maggot, seedcorn beetle), the seed and below-ground parts of the seedling (wireworm, sugarcane beetle), they may be more limited to the roots (white grubs), or attack the under-ground stem (sandhill cutworm). White grub is a generic term for the larval stage of insects like the Japanese beetle, European chafer, and May or June beetles. True white grubs are the larval stage of May and June beetles. To identify the grubs, the raster pattern, or the setae (hair) pattern on the posterior end is used. The Ontario Ministry of Agriculture, Food, and Rural Affairs has developed an excellent publication, Agronomy Guide for Field Crops, that can be used to help identify white grubs in the field. Corn rootworm larvae may be present during the later stages of early season growth but may be too small to readily detect. If detected, they will have a brown to black head and a brown to black anal plate.

Wireworms.

Wireworms.
Frank Peairs, Colorado State University, Bugwood.org.

Seed corn maggot.

Seed corn maggot.

White grub.

White grub.
Corn rootworm larvae.
Scott Bauer, USDA Agricultural Research Service, Bugwood.org

Above-Ground

Some of these insect pests feed above-ground but can also be found under-ground. The cutworm species feed above-ground at night but spend the day under soil clods.

Black cutworm.

Black cutworm.
Roger Schmidt, University of Wisconsin-Madison, Bugwood.org.

Claybacked cutworm.

Claybacked cutworm.
James Kalisch, University of Nebraska, Bugwood.org

Maize billbug.

Maize billbug.
Clemson University - USDA Cooperative Extension Slide Series, Bugwood.org

Common Stalk Borer.

Common Stalk Borer.
James Kalisch, University of Nebraska, Bugwood.org

European corn borer.

European corn borer.
Frank Peairs, Colorado State University, Bugwood.org.

Millipede.

Millipede.
Joseph Berger, Bugwood.org.