Identification of Early Season Insects in Corn

Early Season Corn Insect Pests, VE to V8 

 

Corn Growth Stages

VE V2 V4 V6 V8 V10 V12 VT R1
BELOW-GROUND INSECT PESTS
SEEDCORN MAGGOT  
       
SEEDCORN BEETLE  
             
SUGARCANE BEETLE 
             
WHITE GRUBS
           
WIREWORM
           
SANDHILL CUTWORM
           
     
 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
 
     
1ST GENERATION SOUTHWESTERN CORN BORER
 
     
1ST GENERATION SOUTHERN CORN BORER
 
ABOVE-GROUND NON-INSECT PESTS
MILLIPEDES
               
SLUGS
           

Below-Ground 

 

When searching for below-ground pests, a small garden trowel or pocket knife is a handy tool to use. Some early-season insects are found attacking the seed (seedcorn maggot, seedcorn beetle) others may attack the seed and below-ground parts of the seedling (wireworm, sugarcane beetle), others are more limited to the roots (white grubs), and some attack the under-ground stem (sandhill cutworm). White grub is a generic term for the larval stage of insects like the Japanese beetle, rose or sand 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. Michigan State University has developed an excellent publication, Severe grub damage spotted in northern Michigan hay field, 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.  

Early Season Corn Insect Pests, VE to V8 
IM

Wireworms.  

Frank Peairs, Colorado State University, Bugwood.org. 

Seed corn maggot damage; seed corn maggot larvae feeding on soybean seedling

Seed corn maggot. 

Photo courtesy of Alton N. Sparks, Jr., University of Georgia, Bugwood.org.

White grub. 

Alton N. Sparks, Jr., University of Georgia, Bugwood.org. 

Sugar cane beetle

Sugarcane beetle.  

Clemson University - USDA Cooperative Extension Slide Series.  

Sandhill cutworm.

Sandhill cutworm.  

James Kalisch, University of Nebraska, Bugwood.org     

Corn rootworm larvae.

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 

Southern corn stalk borer.

Southern corn stalk borer.  

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

European corn borer.

European corn borer.  

Frank Peairs, Colorado State University, Bugwood.org. 

Southwestern corn borer.

Southwestern corn borer.  

Frank Peairs, Colorado State University, Bugwood.org. 

Millipede.

Millipede.  

Joseph Berger, Bugwood.org.  

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