maize billbug MER copy.jpg

Maize billbug grub


  • Adult: Shiny, black, ½"-long weevil but often so covered in dirt that it looks like a small clod. It is often found attached, upside-down, to seedling cornstalks near the ground.
  • Larvae: Cream-colored worm with a reddish-brown head capsule.
  • Eggs: White or gray, kidney-shaped and laid in a hole gouged into the plant stem.

Timing of damage: VE to V8

Type of damage: A line of holes running across the leaf, tillering, stunting, distortion and sometimes plant death.

Scouting: Examine 20 consecutive plants in five locations (100 plants total) and note number of 
damaged plants and presence of billbugs.

Economic threshold: Treat only when plants are being severely damaged or killed.

Similar Pests

Ask an Agronomist