Common names: Armyworm, African armyworm (Okalambo), Rice armyworm.
Latin names: Spodoptera and Pseudaletia spp. Common species include Pseudaletia unipuncta (Haworth) and Spodoptera exempta (Walker).
Damage to plants
- Entire leaves and young plants can be consumed during severe infestation.
- ‘Window pane’ damage to leaves caused by newly emerged larvae, which feed by scraping the leaf surface without perforating it.
- Ragged leaf appearance from the leaf edges inwards, also due to feeding.
- Under severe infestation the entire foliar tissue might be lost, with only midribs remaining. Lower leaves are consumed first.
- Large number of caterpillars migrating across fields and roads.
- Worm frass (feces) on the ground below plants.
Factors favoring insects / pest development
- Moths are attracted to vegetation and therefore no-tillage maize and weedy fields are targets for oviposition.
- Prevailing wind currents can aid adult moth dispersal.
- Cold, wet planting seasons that follow drought years favor armyworms due to a reduction in natural predators and parasitoids.
- Armyworm is globally distributed through the tropics and subtropics.
- It is also found in Europe, Russia, and the United States.