- Worldwide distribution. Not recorded in Oceania. On shallot, onion and relatives, food legumes, and potato and cabbage families. Usually, a minor pest in Pacific islands.
- Young caterpillars scrape the surface of outside leaves; larger ones make holes and eat all the leaves.
- Eggs hatch and larvae stay together at first then fan out until there is only one per plant. They pupate in the soil, producing a moth that is a strong flyer.
- Cultural control: handpick; grow under nets; mass trapping using lights; weed; 1-2-year crop rotations.
- Chemical control: PDPs: chillies, neem, pyrethrum, or derris; or, if grown for sale, Bt (Bacillus thuringiensis) on young caterpillars.
Pacific Pests, Pathogens, Weeds & Pesticides
Shallot Spodoptera army worm (178)
Photo 1. Caterpillar damage on onion leaves caused by Spodoptera sp. Often the caterpillars are found inside the tubular leaves.
The species damaging to shallot in Pacific island countries has not been identified. In this fact sheet, it is assumed to be either Spodoptera exigua (common cutworm, beet armyworm, small mottled willow moth), or Spodoptera litura (taro cluster caterpillar) (see Fact Sheet no. 31).
Spodoptera exigua (or Spodoptera litura). Confirmation required.
AUTHOR Grahame Jackson & Mani Mua
Information for Spodoptera litura: from Carmichael A, et al. (2008) TaroPest: an illustrated guide to pests and diseases of taro in the South Pacific. ACIAR Monograph No. 132, 76 pp. (https://lrd.spc.int/about-lrd/lrd-project-partners/taropest); and from Carmichael A (2008) Cluster Caterpillar (Spodoptera litura). PaDIL - http://www.padil.gov.au. Information on Spodoptera exigua: from MAF Plant Health & Environment Laboratory (2011) Beet armyworm (Spodoptera exigua): PaDIL - http://www.padil.gov.au; and Capinera JL (2020) Beet armyworm. Featured Creatures. UF/IFAS. University of Florida. (http://entnemdept.ufl.edu/creatures/veg/leaf/beet_armyworm.htm); and Spodoptera exigua (Hubner, 1808) (undated) Atlas of Living Australia. (https://bie.ala.org.au/species/urn:lsid:biodiversity.org.au:afd.taxon:35e15238-b120-49c9-a3d7-0bd177c3afad); and from Basuki SR (2011) Farmers' knowledge and effectiveness of insecticide uses by farmers in controlling Spodoptera exigua on shallots in Brebes and Cirebon. Indonesian Journal of Agriculture 4(1): 22-32. (https://ei-ado.aciar.gov.au/supplementary-reports/annotated-bibliography/farmers-knowledge-and-effectiveness-insecticide-uses.html). Photo 1 Ooi P (Image ID 38351). Photo 3 Frank Peairs, Colorado State University, Bugwood.org. Photo 5 Robert J. Bauernfeind, Kansas State University, Bugwood.org.
Produced with support from the Australian Centre for International Agricultural Research under project PC/2010/090: Strengthening integrated crop management research in the Pacific Islands in support of sustainable intensification of high-value crop production, implemented by the University of Queensland and the Secretariat of the Pacific Community.