The wicked witchweed
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CTA. 2002. The wicked witchweed. Spore 98. CTA, Wageningen, The Netherlands.
Permanent link to this item: http://hdl.handle.net/10568/46486
Internet URL: http://spore.cta.int/images/stories/pdf/old/spore98.pdf
Striga or witchweed (Striga hermonthica) is well on its way to joining the list of the world s worst weeds, and is already top of list of many an African farmer. It is a parasitic weed that penetrates the roots of other plants, diverting nutrients...
Striga or witchweed (Striga hermonthica) is well on its way to joining the list of the world s worst weeds, and is already top of list of many an African farmer. It is a parasitic weed that penetrates the roots of other plants, diverting nutrients and water from the host plant and thus stunting their growth. Striga occurs mainly in cereal crops, such as maize, sorghum, fonio and millet, but Striga spp. also affects cowpeas and groundnuts. It has infested mainly the savanna areas in Africa and accounts for an estimated loss of 40 million tonnes of cereal annually continent-wide. Striga especially hits Benin, Burkina Faso, Cameroon, Mali, Nigeria, Sudan and Togo, but it is also present in the eastern and southern parts of the continent. In Kenya, striga is being fought off by planting desmodium (see box). The International Institute of Tropical Agriculture (IITA) in Nigeria has devoted years to developing resistance in cereals against striga. By combining resistance in certain maize races with varieties that have a good production, IITA researchers have managed to breed striga tolerance in maize. Calliandra calothyrsus and Croton megalocarpus, both popular agroforestry tree species, release allelopathic (growth inhibiting) compounds into the environment which reduces striga infestation. The most straightforward method of weed control, after all is said and done, is probably through a acombination of measures such as intercropping with N-fixing and Striga repelling plants, and maintaining or increasing soil fertility.