Pacific Pests, Pathogens and Weeds - Online edition

Pacific Pests, Pathogens, Weeds & Pesticides

Taro corm rots - post-harvest (179)

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  • Worldwide in the tropics, on many crops. Important diseases.
  • Fungi, water moulds (oomycetes) and bacteria cause the rots. They enter corms at harvest when suckers are broken off. The common ones are: (i) Athelia – pink with white border; (ii) Pythium - white crumbly rot; (iii) Phytophthora taro leaf blight - firm brown rot; (iv) Lasiodiplodia - black, spongy, sour-smelling rot; and (v) Erwinia - soft rot.
  • Cultural control: harvest, remove suckers and soil, and store in (i) leaf-lined soil pit, or (ii) plastic bags or (iii) plastic-lined cardboard boxes, if for markets.
  • Chemical control: improve storage in plastic bags by first dipping corms in bleach (1% for 1-2 mins).
Common Name

Taro corm rots (post-harvest)

Scientific Name

The following are the commonly recorded rots that develop in taro corms after harvest:

Athelia rolfsii (see Fact Sheet no. 11)
Lasiodiplodia (Botryodiplodia) theobromae
Pythium splendens
Phytophthora colocasiae (see Fact Sheet no. 14)
Erwinia species: Erwinia carotovora subsp. carotovora (see Fact Sheet nos. 101, 214, 289, 296); now renamed Pectobacterium carotovorum subsp. carotovorum, and
Erwinia crysanthemi.

AUTHOR Grahame Jackson
Information from and from Biosecurity Australia (2011) Review of import conditions for fresh taro corms. Biosecurity Australia, Canberra. (; and 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. (

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.

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