Pacific Pests, Pathogens, Weeds & Pesticides - Online edition

Pacific Pests, Pathogens, Weeds & Pesticides

Passionfruit Phytophthora rot (154)

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Photo 1. Stem rot, water mould, Phytophthora nicotianae. Rots are purple at first, later brown. When they girdled the stem they cause a wilt.

Photo 2. Fruit rot caused by the water mould, Phytophthora nicotianae. Rots are grey-green at first and later light brown.

Summary

  • Worldwide distribution. On passionfruit, cultivated and wild. Note, this is the same fungus that causes a similar disease on tomato (root rot, and a firm dark fruit rot; see Fact Sheet no. 157), and also attacks capsicum, citrus (see Fact Sheet no. 264), papaya (see Fact Sheet no. 152), pineapple, and tobacco.
  • A water mould, an oomycete, not a fungus.
  • A blight of young leaves, brown spots on older ones, rots on fruits and vines; root decay causing wilts.
  • Spread by rain splash from spores in the soil; long distance spread is on wind-driven rain, and perhaps on nursery plants.
  • Cultural control: yellow variety rootstocks with graft 30 cm above soil; avoid planting in poorly drained land; prune to aid air circulation and drying; grass barriers to stop rain-splash; collect trash and burn after harvest.
  • Chemical control: copper or mancozeb (protectants); or phosphorous acid (systemic).

Common Name

Fruit rot, Phytophthora blight

Scientific Name

Phytophthora nicotianae; previously, Phytophthora nicotianae pv. parasitica. Note that in Fiji Phytophthora cinnamomi has also been reported as the cause of collar rot.

AUTHOR Grahame Jackson
Information (and Photo 2) from Gerlach WWP (1988) Plant diseases of Western Samoa. Samoan German Crop Protection Project, Deutsche Gesellschaft für Technische Zusammenarbeit (GTZ) Gmbh, Germany; and from CABI (undated) Phytophthora blight on passion fruit Phytophthora nicotianae var. parasitica. Plant Knowledge Bank. (https://www.plantwise.org/knowledgebank/factsheetforfarmers/20137804235); and from DAF (2016) Managing passionfruit plantations affected by wet weather. (https://www.daf.qld.gov.au/__data/assets/pdf_file/0016/57202/factsheet-passionfruit-and-wet-weather.pdf). Photo 1 Diseases of vegetable crops in Australia (2010). Editors, Denis Persley, et al. CSIRO Publishing.

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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