Bondi Junction NSW, Australia
Fact Sheets
Tomato late blight (261)
Pacific Pests, Pathogens and Weeds
Pacific Pests, Pathogens and Weeds


  • Worldwide distribution. On tomato, potato and wild species in the potato family. There is evidence of strains attacking different hosts. An important disease.
  • A water mould, or oomycete, not a fungus.
  • Irregular patches on leaves; white cottony growth with spores on undersides. Leaves yellow, shrivel and fall. Dark brown, firm fruit rot. Worse in cool, wet weather.
  • Spread by wind or wind-driven rain, up to 20 km; and on seed for planting.
  • Cultural control: check plants in nursery; avoid planting near older plants; space plants to aid air movement; intercrop; stake; mulch; drip rather than overhead irrigation; tolerant varieties; crop rotation.
  • Chemical control: copper, mancozeb or chlorothalonil, alone, or alternate with, e.g., metalaxyl, cymoxanil, dimethomorph or strobilurins. Phosphorus acid either alone or with chlorothalonil.

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