Ergot threat to sorghum
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CTA. 1998. Ergot threat to sorghum. Spore 73. CTA, Wageningen, The Netherlands.
Permanent link to this item: http://hdl.handle.net/10568/48977
Internet URL: http://spore.cta.int/images/stories/pdf/old/spore73.pdf
Sorghum is an important crop in semi-arid parts of Africa, as well as in other parts of the world. It is a particularly useful crop in that it is more drought-tolerant than many other grain crops. However, the disease ergot or honeydew is becoming a...
Sorghum is an important crop in semi-arid parts of Africa, as well as in other parts of the world. It is a particularly useful crop in that it is more drought-tolerant than many other grain crops. However, the disease ergot or honeydew is becoming a growing threat to sorghum worldwide. Ergot is a serious disease of sorghum that affects the production of F1 hybrid seeds, particularly if 'nicking' is poor or seed-set is delayed in male-sterile lines. A disease of the ovaries, ergot reduces grain yield because infected flowers do not produce grain. In addition, it reduces germination and seedling emergence and predisposes seedlings to other diseases. The resultant grain is of lower quality and because of the sticky secretion produced by one type of the disease, threshing is difficult. Ergot is not only damaging to the crop itself, but poses a serious human health risk due to the dangerous toxins that the disease can produce. The ergot disease now has serious implications for export of sorghum from one country or one region to another. Quarantine regulations will have to be rigorously applied as it has been found that the ergot pathogen has an extraordinary capacity to spread rapidly. In Brazil, in South America an epidemic of the disease covered 800,000 km2 in a week in 1995, and in 1996 in Queensland, Australia it spread over 60,000 km2 in three weeks. Scientists have found that the measures that best reduce the incidence of ergot are to sow only seed that has been produced from ergot-free areas; to alter sowing dates to allow flowering when environmental conditions do not favour the disease development (during wet or high humidity conditions); to rogue infected plants; and to spray seed production plots with a triazole fungicide 3-4 times at 5-7 days intervals, starting before stigma emergence. The International Crops Research Institute for the Semi-Arid Tropics Patancheru PO Andhra Pradesh 502 324 INDIA