Pacific Pests, Pathogens and Weeds - Online edition

Pacific Pests, Pathogens, Weeds & Pesticides

Sweetpotato weevil (029)

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  • Worldwide distribution. On sweetpotato and wild Ipomoea (morning glory). An important pest.
  • Adults lay eggs in base of the stem ('crown') and in storage roots, and larvae tunnel through them. Adults eat the leaves and surface of the vines.
  • Damage is the same as done by West Indian weevil. Worse in dry times, and in light sandy soils.
  • Spread by adults on the wing, and in cuttings and storage roots.
  • Cultural control: early, deep rooting varieties; plant only tip cuttings; remove wild morning glory; hill-up, covering cracks during dry times; ideally, make one-time harvest; 3-4-year crop rotation; after harvest, collect and destroy vines and infested storage roots.
  • Chemical control: treat vines (bifenthrin); treat plants in field every 3-4 weeks (bifenthrin or fipronil).
Common Name

Sweetpotato weevil

Scientific Name

Cylas formicarius

AUTHORS Helen Tsatsia & Grahame Jackson
Information from Brookes D, et al. (2019) Origins, divergence, and contrasting invasion history of the sweet potato weevil pests Cylas formicarius (Coleoptera: Brenttidae) and Euscepes batatae (Coleoptera: curculionidae) in the Asia-Pacific. Journal of Economic Entomology XX(XX): 1-9. (; and CABI (2020) Cylas formicarius (sweet potato weevil). Invasive Species Compendium. (; and from O'Sullivan J et al. (undated) Sweetpotato DiagNotes: A diagnostic key and information tool for sweetpotato problems. ( Photos 1,4,5,6 & 8 Russell McCrystal, Bundaberg, Queensland.

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 for the Pacific Community.

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