Pacific Pests, Pathogens, Weeds & Pesticides - Online edition

Pacific Pests, Pathogens, Weeds & Pesticides

Maize northern leaf blight (226)

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Photo 1. Large elongated grey spots of maize northern leaf blight, Setosphaeria turcica.

Photo 2. Spots of maize northern leaf blight, Setosphaeria turcica, starting to form dark masses of spores.

Diagram. Disease cycle of maize northern leaf blight (NLB). The spores are called 'conidia', and the cottony growth of the fungus, the 'mycelium').

Summary

  • Worldwide distribution. On maize, sorghum and wild grasses. An important disease.
  •  Large, oval, grey or light brown, spots, 25-150 mm, sometimes with dark margins. Spots merge. Brown spore masses in rings. Leaves dry out and die.
  • Spread is by rain splash and wind.
  • Cultural control: resistant varieties; adequate amounts of P and K, but do not over supply N; weed, especially grasses; crop rotation; collect and burn trash after harvest.
  • Chemical control: unlikely to be economic; if needed use chlorothalonil and mancozeb.

Common Name

Maize leaf blight, maize northern leaf blight

Scientific Name

Setosphaeria turcica; the asexual stage name is Exserohilum turcicum. It has also been known as Helminthosporium turcicum. There are many races or strains of the fungus.

AUTHOR Grahame Jackson
Information from CABI (2012) Setosphaeria turcica (maize leaf blight). Crop Protection Compendium. (https://www.cabi.org/cpc/datasheet/49783). Photos 1&2 Kohler F, et al. (1997) Diseases of cultivated crops in Pacific Island countries. South Pacific Commission. Pirie Printers Pty Limited, Canberra, Australia. and Setosphaeria turcica. Wikipedia. (https://en.wikipedia.org/wiki/Setosphaeria_turcica); and Diagram (and information) Svec L, Dolezal B (undated) Crop insights: managing northern corm leaf blight race shifts. Pioneer. (https://www.pioneer.com/us/agronomy/Managing-Northern-Corn-Leaf-Blight.html/).

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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