Hop Vine Borer

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Injury and Symptoms

Hop vine borer larvae tunneling at bottom of corn stalk (left photo). Hop vine borer injury below-ground portions on stalk (right photo).
  • Larvae tunnel upward from the bottom of the stalk; injury is confined
    to below-ground portions of stalk (see yellow arrows above)
  • Tunneling usually kills the plant
  • Infestations in corn are associated with: 
    • areas of grassy weeds
    • field edges, terraces, or waterways where perennial grasses occur
    • no-till or conservation-till fields with poor grass control the previous year
    • continuous corn production and poor grass control
Corn stand loss in northeast Iowa due to hop vine borer.

Stand loss in northeast Iowa (note grassy weeds in field).

Facts of Hop Vine Borer

  • Common name: hop vine borer
  • Latin name: Hydraecia immanis, family Noctuidae
  • Description
    • Adult: dull brown moth with buff-colored front forewings and dull-white hind wings; wingspan 1½ inches
    • Larva: solid orange or reddish-brown head with black eyes; large dark purple or brown spots, almost square-shaped, along the back with transverse rows along the side, and separated by contrasting dirty white lines
    • Egg: brown and oval, often laid in parallel rows, hidden under dried grass leaves and sheaths
hop vine borer larva

Larva of hop vine borer

  • Origin and distribution: 
    • Native to North America
    • Central and eastern Corn Belt from western Iowa to southern Ohio and New York
  • Similar species: 
    • Potato stem borer, which is light red or pink, occurs mostly north of the Great Lakes and in the St. Lawrence River Valley

Pest Status and Importance

  • Occasional or rare pest of early vegetative corn
  • Stand loss is possible in areas of grassy weeds
  • Damage mostly reported from northern Illinois, northeastern Iowa, southeastern Minnesota and southern Wisconsin

Life History of Hop Vine Borer

  • One generation per year
  • Overwintered eggs hatch in late April and early May
  • Larvae have six, or occasionally seven, stages
  • First-stage larvae tunnel into grass stems such as smooth brome grass, quackgrass, orchard grass, woolly cupgrass, and wirestem muhly
  • Third- and fourth-stage larvae outgrow grass stems and move to corn
  • Large larvae prefer only corn and hops
  • Larvae pupate in the soil in early July
  • Adults emerge during late July and August
  • Females lay eggs on grasses
Reported Midwest distribution of hop vine borer.
Corn plant with 'dead heart' killed by hop vine borer.

Photo above: Corn plant with "dead heart" killed by hop vine borer.

Stand loss caused by hop vine borer.

Photo above: Stand loss caused by hop vine borer.

Integrated Pest Management Practices

  • Weed management
    • Do not allow grassy weeds to proliferate in corn
    • Eliminate grassy weeds before late summer to remove egg-laying sites
  • Insecticides
    • Broad spectrum insecticides labeled for cutworms may provide control, but only if applied at corn emergence and before larvae tunnel into the stem
  • Insecticide seed treatments
    • Seed treatments are not labeled for this insect
  • Bt corn
    • Products containing Cry1Ab or Cry1F traits are not labeled for this insect
Hop vine borer larva

Photos and Text
Marlin E. Rice, Pioneer
Reviewed by Herb Eichenseer and Paula Davis (Pioneer)