Key Points

  • Common stalk borer is a sporadic and infrequent pest of corn in much of North America.
  • Damage to corn is most common near field borders, waterways, or terraces, and in continuous corn.
  • Several available Bt corn technologies provide control or suppression of common stalk borer larvae.

Pest Facts and Impact on Crop

  • Latin name: Papaipema nebris.
  • Native to North America; may be found in most areas east of the Rockies.
  • Sporadic and infrequent pest of corn; incidence increases with no-till or grass weed infestation.
  • Highest incidence usually occurs in rows closest to grass field borders, waterways, or terraces with large weeds (e.g., giant ragweed), or in continuous corn.
  • Development begins in grasses, but larvae move at about 1400 - 1700 GDU (base 41 °F) to larger hosts, including nearby corn.
  • Primary hosts are corn, quackgrass, giant ragweed, wirestem muhly, tomato, and occasionally soybeans.
  • Has no known significant natural enemies.

Photo - closeup stalk borer larva on leaf

Stalk borer

Injury Symptoms

  • Stalk borers tunnel into corn stalks above the soil or climb directly into the whorl resulting in tattered leaves.
  • Young plants (VE-V3) may be killed by tunneling below the growing point.
  • On older plants (V4-V8), the leaves will usually discolor, wilt, and die if tunneling is between them and the growing point; often called “dead heart.”
  • Plants infested after the V8 stage usually show little visible injury.
  • Non-lethal infestations in early-stage plants cause stunting, tillering, delayed development, and increase frequency of barren plants, reducing yield.

Photo - growing corn plant damaged from common stalk borer

Dead "heart"

Photo - stunted ears on corn plant - insect damage

Stunted ears

Photos - Side by side - stalk borer tunneling into plant stalk and damaged corn plant

Tunnel in corn stalk.

Pest ID - Key Characteristics

  • Stalk borer larvae are cream to light brown with a dark purple saddle on the forward half of the body.
  • Larvae have dark streaks on either side of their heads.
  • As larvae grow, the purple becomes dilute and faded.
  • Larvae are about ½ inch long when they leave grass and will reach nearly 2 inches at full development before fall.

Photo - Early-stage stalk borer head - closeup

Early-stage stalk borer head

Photo - early-stage stalk borer on leaf - closeup

Early-stage stalk borer.

Photo - late-stage stalk borer on leaf - closeup

Late-stage stalk borer.

Areas Prone to Common Stalk Borer Injury

Photo - insect egg laying site - grass terrace corn field

Egg laying site: grass terrace.

Photo - stunted corn plants in border rows infested with stalk borers.

Stunted corn in border rows infested with stalk borers.

Photo - insect egg laying site - giant ragweed and grasses

Egg laying site: giant ragweed and grasses.

Management Considerations

  • Tillage or herbicide grass control in the prior fall will reduce ovipositional attractiveness.
  • Burning grassy field borders before planting may destroy eggs.
  • Begin scouting at about 1300 GDU (41° base) accumulation since January 1.
    • Grassy or weedy field edges, such as shelterbelts, terraces, waterways.
    • No-till fields with heavy vegetation prior to burn down.
  • Resistance available
    • Several available Bt corn technologies provide control or suppression of common stalk borer larvae.
  • Pesticide use and timing
    • Most effective if timed when larva are leaving host plants after a herbicide application.
    • Maximum 80% effective when used on infested plants, spray only infested areas of the field.
    • On corn plants below V6, less than 10% infestation may warrant spot treatment, later than V7 nearly 100% of the plants must be infested to warrant treatment

Pest ID - Related/Confused Species

Several species share the same habitat and may cause similar looking injury.

Other borers:

Photo - Eurpean corn borer - no purple

Eurpean corn borer - no purple

Photo - Corn earworm - multicolored stripes

Corn earworm – multicolored stripes

Photo - Hop vine borer - no stripe on side of head - burrows up from root

Hop vine borer – no stripe on side of head, burrows up from root

Photo - Fall armyworm - multicolored stripes

Fall armyworm – multicolored stripes

Photo - Southwestern corn borer - dark spots - no stripe on side of head

Southwestern corn borer – dark spots, no stripe on side of head

Photo - Lesser cornstalk borer - purple bands - not striped

Lesser cornstalk borer – purple bands - not striped

Other seeding feeders:

  • Billbug, wireworm, cutworm

Stalk Borer Annual Cycle

Timeline - common stalk borer life cycle.

Click here or on the image above for a larger view.

Photo - man on phone walking in cornfield - midseason - cloudy sky

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