Fall armyworm moth

Spodoptera frugiperda

1. Identification

• Common name: Fall armyworm
• Scientific name: Spodoptera frugiperda J.E. Smith
• Order: Lepidoptera
• Family: Noctuidae

2. Pest description

• Caterpillars of variable coloration (green, brown, greyish), with a characteristic dorsal pattern in the shape of an inverted “Y” on the head.
• Medium-sized adults, with brownish forewings and pale hindwings with a dark margin.
• A highly polyphagous species, with a great capacity for dispersal and migration.
• It mainly attacks young tissues, leaf whorls and reproductive structures.

3. Main hosts

• Maize.
• Sorghum.
• Rice.
• Cotton.
• Various cultivated and wild vegetables and grasses.

4. Symptoms and damage

• Intense scrapings and perforations on young leaves.
• Damage to the maize whorl, with accumulation of excrement.
• Perforations in panicles, ears and young fruits.
• Significant reduction in yield and quality.
• Young plants may be destroyed in severe attacks.

5. Biological cycle

• Several generations per year, accelerated in warm climates.
• Eggs laid in masses, usually on the underside of the leaves.
• Very voracious caterpillars, with rapid development.
• Pupation in the soil, in shallow chambers.
• Adults with a strong migratory capacity and continuous activity in tropical and subtropical regions.

6. Monitoring

• Observation of scrapings and perforations on young leaves.
• Inspection of the maize whorl to detect caterpillars and excrement.
• Pheromone traps for detection and flight tracking.
• Assessment of the percentage of damaged plants through direct sampling.

7. Management measures

• Cultural: destruction of crop residues, crop rotation and staggered sowing.
• Preventive: choice of more tolerant varieties and practices that reduce the attractiveness of young plants.
• Biological: application of Bacillus thuringiensis and use of parasitoids such as Trichogramma spp..
• Integrated protection: monitoring with pheromones, definition of intervention thresholds and judicious application of authorised insecticides.

Bibliographic references

• EPPO Global Database – Spodoptera frugiperda.
• CABI Invasive Species Compendium – Spodoptera frugiperda.
• FAO – Fall Armyworm Monitoring and Early Warning System (FAMEWS).
• USDA APHIS – Fall Armyworm information page.
• Goergen, G., et al. (2016). First report of outbreaks of the fall armyworm Spodoptera frugiperda in West and Central Africa. PLOS ONE, 11(10): e0165632.