For many years, farmers in Tanzania have desperately tried to control the parasitic flowering plant Striga spp.—popularly known as witchweed—that can make maize farming nearly impossible in regions of heavy infestation. In Tanzania Striga infests an estimated 0.6 million hectares over 10 regions, causing yearly losses to farmers of some 1.7 million tons of grain worth US$ 350 million. For lack of cost-effective control measures for this pest, some farmers have stopped growing maize.
However, there is now hope, thanks to a new maize variety, that is effective in controlling Striga. The variety, TAN222, has the added advantage of being high yielding 3.7 tons per hectare, according to Isaka Mashauri, director of Tanseed International, the company that is commercializing the variety in Tanzania.
Many years of joint research by CIMMYT, BASF (a multinational producer and supplier of agrochemicals), and the Weizmann Institute of Science in Israel have resulted in a solution and source of hope for farmers. It involves coating seed of a herbicide-tolerant maize variety with the systemic herbicide imazapyr. When the seed is sown and sprouts, any Striga plants that attack it are killed. As part of this research, the partners developed herbicide tolerant maize lines based on a natural mutation in maize.
The African Agricultural Technology Foundation (AATF) is promoting this technology among farmers and extension agencies in areas of sub-Saharan Africa where Striga is prevalent. In Tanzania, the seed company Tanseed International has used the herbicide tolerant lines from this effort to develop and market the maize variety TAN222.
Anatia Mike, a farmer in Muheza District, Tanzania, tried using herbicide-coated seed of TAN222 and managed to harvest 1.2 tons of grain per hectare from her Striga infested farm, where previously she was getting yields of only 0.5 tons. At a recent field day organized by the research partners on Mike’s homestead to demonstrate the efficacy of this technology, Karimu Mtambo, the Director of Tanzania’s Ministry of Agriculture, Food Security, and Cooperatives, lauded the practice as the best and most effective in controlling Striga and improving maize yields, and called on farmers to adopt it together with other good agricultural practices.
Also present were Mashauri; Denis Tumwesigye Kyetere and Gospel Omanya, Executive Director and Seed Systems Manager, respectively, AATF; BASF representative Sammy Waruingi; Ibrahim Matovu, Muheza District Commissioner; and from CIMMYT agronomist Fred Kanampiu and breeder Dan Makumbi.
Kyetere promised full support from AATF in scaling out the technology, and Kanampiu called on the government to put in place mechanisms like herbicide registration for commercial use that would facilitate speedy adoption of the technology. He also urged seed companies to work with the Ministry of Agriculture to educate farmers on its use. Matovu promised to have Striga control included in the district agenda, particularly in budgeting.