Southwestern maize borer

Also known as Southwestern corn borer
Diatraea grandiosella

Damage to plants

  • Feeding in the whorl causing dead heart.
  • Tunneling of the stems and ears causing interference with nutrient and water translocation.
  • Boring in the ears, which can increase prevalence of ear rots.
  • Girdling of the stem near the soil surface, causing lodging.


  • Pinholes and perforations in young leaves emerging from the whorl.
  • Tunneling in the stems and ears.
  • Lodging.
  • Dead heart.

Factors favoring insects / pest development

  • Reduced tillage methods will allow larvae to overwinter in infested crop stems.
  • Mild temperatures and low rainfall during the off season will aid the survival of larvae in diapause.
  • Low number of natural predators.

Geographic distribution

  • Southern USA, Central America and the Caribbean.

For extended information click here