European corn borer

Ostrinia nubilalis

1. Identification

• Common name: European corn borer
• Scientific name: Ostrinia nubilalis Hübner
• Order: Lepidoptera
• Family: Crambidae

2. Pest description

• Adults 20–30 mm in wingspan, yellowish wings with wavy patterns.
• Females generally larger and paler than males.
• Larvae cream to pinkish in colour, with a brown head.
• Larvae bore into stems, leaves and ears.
• Presence of internal galleries and fragments of plant tissue.

3. Main hosts

• Maize.
• Sorghum.
• Pepper.
• Bean.
• Potato.
• Various wild host plants.

4. Symptoms and damage

• Borings in the leaves forming “windows”.
• Galleries in the stem that cause breakage and lodging.
• Borings in the ears and damage to the grains.
• Reduction of yield and quality.
• Greater susceptibility to secondary fungal infections.

5. Biological cycle

• One to two generations per year in temperate climates.
• Eggs laid in clusters on the underside of the leaves.
• Larvae develop inside the stem and the ears.
• Pupation inside the galleries or in the crop residues.
• Adults emerge in spring and summer.

6. Monitoring

• Observation of egg masses on the leaves.
• Checking for borings and galleries in stems and ears.
• Monitoring with pheromone traps to detect flights.
• Recording of damage in plots with a history of the pest.
• Assessment of attack intensity to determine the need for intervention.

7. Management measures

• Cultural: destruction of crop residues, crop rotation and choice of less susceptible varieties.
• Biological: use of Trichogramma spp. as biological control agents when authorised.
• Integrated protection: monitoring with pheromones, interventions only when justified, judicious application of authorised insecticides and integration of cultural practices to reduce population pressure.

Bibliographic references

• EPPO Global Database – Ostrinia nubilalis.
• CABI Invasive Species Compendium – O. nubilalis.
• Malvar, R. A. et al. (2008). European corn borer management in maize.
• Showers, W. B. et al. (1993). Biology and ecology of the European corn borer.