Sweetpotato weevil

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Scientific Name: Cylas formicarius Fabr.


  Larvae tunnelling in stem (N. Talekar).

Adult male sweetpotato weevil.

Diagnostic summary

  • What they do to plants

- larvae feed and tunnel into the stems and storage roots.


- adult weevils feed on the tender buds, leaves, stems and storage roots.

  • What you see on  plants

- damage is characterized by small feeding and ovipositional punctures on the stem and storage root surface and larval tunnels filled with frass on the tissues.  


- larval feeding causes thickening, drying and cracking of the stem.

  • Larval stage is  the most destructive stage.

  • Severely damaged roots become bitter, emit terpene odour, less marketable if not unmarketable.

  • Early detection can be done by checking the base of the plant for feeding punctures and exit holes.

  • Hot, dry weather favours weevil development.

  • Found throughout the tropical and subtropical regions worldwide except in some parts of Africa.


Economic importance

Geographical distribution



Biology and ecology

Detection and inspection



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Other weevils