Pacific Pests, Pathogens and Weeds - Online edition

Pacific Pests, Pathogens, Weeds & Pesticides

Fall armyworm (401)

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  • Widespread, and spreading. Present in Asia, but not Indonesia, the Philippines, Oceania. Hosts: maize, millets, rice, sorghum, sugarcane, and many others of economic importance.
  • Damage: larvae eat leaves and bore into fruits, e.g., maize cobs. Crops losses across Africa since 2016 have cost billions of dollars.
  • Eggs masses (up to 200) on underside of leaves. Young larvae green, feed together, later brown with three whitish lines along back, dark spots with spines, and upside-down Y on head. Larger larvae cannibalistic and nocturnal. Adults, brown forewings and white hindwings, up to 40 mm wingspan.
  • Spread is rapid on the wing, and on air currents. Highly invasive.
  • Natural enemies: many parasitoids and predators known, and pathogens.
  • Cultural control: avoid overlapping crops; avoid planting new crops next to old; plant napier or Brachicaria grass (attracts moths) around crops, and Desmodium (repels moths) between crops; monitor; crush egg masses; bird perches; attract ants; ash for maize whorls; collect and burn debris after harvest,
  • Chemical control: biorational pesticides: (i) botanicals (chillies, neem, derris, pyrethrum); (ii) microbials e.g., Bt (Bacillus thuringiensis subspecies kurstaki) against young caterpillars, spinosad, Beauveria; (iii) avoid other kinds of pesticides as moths have resistance to them, or will develop it, and (iv) will kill natural enemies.
Common Name

Fall armyworm. Named after its flight into North America where it lays eggs, and the larvae develop in the Fall or Autumn.

Scientific Name

Spodoptera frugiperda

AUTHOR Grahame Jackson
Information from John Wightman (2019) Fall armyworm update. Natural Resource Development Maleny Queensland. (; and CABI (2019). Spodoptera frugiperda (fall armyworm) Crop Protection Compendium. (; and Fall armyworm. Wikipedia. (; and FAO FAMEWS V3 app; and FAO Fall Armyworm Guidance Notes 1-5. (; and from Kris Wyckhuys. Hanoi, Vietnam. Photo 1 Russ Ottens, University of Georgia, Photo 2 Frank Peairs, Colorado State University, Photo 3 John C. French Sr., Retired, Universities:Auburn, GA, Clemson and U of MO, Photo 4 Lyle Buss, University of Florida, Diagram from FAO FAW Guidance Note 2 Fall Armyworm Scouting. (

Produced with support from the Australian Centre for International Agricultural Research under project HORT/2016/18: Responding to emerging pest and disease threats to horticulture in the Pacific islands, implemented by the University of Queensland and the Pacific Community

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