The parasitic angiosperms, Striga hermonthica and S. gesnerioides, obligate root parasites endemic in sub-Saharan Africa, constitute severe constraints to cereal and legume production in West and Central Africa. Over the years, a range of effective component technologies has been identified for Striga control in Africa. The potential of these technologies has been demonstrated under researcher-managed conditions. To promote farmer testing of the technologies, community workshops were conducted in 42 rural communities in Kaduna State, northern Nigeria. These revealed that agriculture was the main source of livelihood for most households. The three most important crops, maize, sorghum and pearl millet are attacked by S. hermonthica, regarded as the major constraint to crop production, often causing 70–100% crop loss. Farmers recognised two types of Striga damage (underground and aboveground), with greater damage being caused by underground Striga. Farmers attributed increasing incidence and severity of Striga damage to lack of capital, poor soil fertility, infestation of previously uninfested land by Striga seeds, and continuous cropping of host crops. The most widely used among the 15 existing Striga control techniques identified by the farmers were hoe weeding and hand pulling, application of inorganic fertilizer and manure, crop rotations, fallowing, and early planting. In assessing possible control measures farmers considered increased crop yield, reduced Striga reproduction and Striga emergence, greater crop vigour, and increased soil fertility as positive attributes. Negative attributes comprised increased labour requirement, higher costs, increased risk of crop damage or yield reduction, and lower quantity and quality of produce. Overall, a legume-cereal rotation was the most highly rated control option for S. hermonthica management evaluated by the farmers. The implications of these results are examined with respect to farmers' adoption and adaptation of Striga control options beyond the experimental plots.

On-farm trials were conducted in the northern Guinea savanna of Nigeria. The objective was to compare integrated Striga hermonthica control measures (soyabean or cowpea trap crop in the first year followed by maize resistant to Striga in the second year) with farmers' traditional practices (cereal-based cropping systems) under farmer-managed conditions.Integrated control proved to be highly effective in terms of reducing Striga incidence both in terms of reduced seed density in the soil and decreased infection in maize. Resistant maize following the soyabean trap crop yielded 1.58 t ha −1 of grain and out-yielded local maize following traditional practices by more than 80%. Similarly, the overall productivity over the period of the experiment was highest with the integrated control treatment using soyabean. Conversely, resistant maize after the cowpea trap crop yielded only 0.92 t ha −1 (possibly due to the poor performance of the cowpea crop in the first year), and maize yields were similar to those obtained with farmer practices. Initial Striga seed density in the soil was negatively correlated (r = −0.33) with soil nitrogen, but nitrogen-fertilizer application rates did not seem to affect the level of Striga infection in maize. I N T RO D U C T I O NStriga hermonthica (Del.) Benth., a root-parasitic flowering plant, is endemic in Africa and constitutes one of the most severe constraints to cereal production in sub-Saharan Africa . Traditional cereal-based cropping systems included prolonged fallow periods that kept Striga infestation at tolerable levels. As land use intensified with more cereal monocropping and reduced fallow periods, infestation levels increased, threatening the livelihood of millions of people. Sauerborn (1991) estimated that more than 5 × 10 6 ha were infested in six West African countries and that around 21 × 10 6 ha might be infested in Africa as a whole, resulting in annual losses of more than four million tonnes of grain (US$ 480 million).Research on S. hermonthica has a long history, and a range of effective component technologies have been identified as effective control methods (Parker and Riches, 1993). Examples are host-plant resistance and the use of trap crops, i.e., non-hosts that stimulate the suicidal germination of Striga seeds and therefore reduce the seed bank

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Two sets of on-farm trials, each covering two years, were conducted in the northern Guinea savannah of Nigeria over the period 1999-2001, the objective being to compare integrated Striga hermonthica control measures (soybean or cowpea trap crops followed by maize resistant to Striga) with farmers' traditional cereal-based cropping systems. In both sets of trials, this proved to be highly effective in increasing productivity over the two year period, especially where soybean was used as a trap crop. Resistant maize after a trap crop increased the net benefit over the two cropping seasons in both trials by over 100 % over farmer practice. However, in the second set of trials there was no significant increase in productivity between a trap crop followed by Striga resistant maize, and a trap crop followed by local maize especially where legume intercropping and fertilizer had been applied in the farmer practice. There was also no increase in productivity between two years' traditional cereal cropping and one year's local maize followed by Striga resistant maize. This indicates the importance of a legume trap crop in the first year in order to ensure high productivity in the second year, regardless of variety. Up to 20 % of farmers obtained higher productivity from their own practices, notably intercropping of cereals with legumes and use of inorganic fertilizers. Leguminous trap crops and Striga resistant maize, together with two key management practices (increased soybean planting density and hand-roguing) were seen to be spreading both within and beyond the research villages, indicating that farmers see the economic benefits of controlling Striga. Survey findings show that explaining the reasons why control practices work can greatly increase the adoption of these practices. Wider adoption of Striga control will therefore require an extension approach that provides this training as well as encouraging farmers to experiment and adapt Striga control options for their local farming systems. I N T RO D U C T I O NStriga hermonthica, a parasitic flowering plant, endemic to Africa, constitutes one of the most severe constraints to cereal production in sub-Saharan Africa. It parasitizes sorghum, maize, millet, rice and sugar cane, as well as pasture and wild grasses, by attaching itself to the roots of the host plant diverting essential nutrients and leaving the host stunted and yielding little or no grain, often causing yield losses in excess of § §

A survey was conducted during dry and rainy seasons of 2011 in order to determine the phytosociological attributes of acquatic weeds of Kano-Hadeja-Nguru wetlands. Random quadrat method was adopted for the phytosociological studies. The study areas consisted of communities from Kano, Jigawa and Yobe States. In each state, six communities were randomly selected. In each community20 quadrats of 4 m 2 size were laid down and hence sum of 120 quadrats were randomly thrown for each state. Within each quadrat area, weeds were identified, counted and weed cover scores were recorded. Weeds were cut at ground level, fresh and dry weights were determined. Typha grass was the most dominant species in the wetlands of Jigawa (21.195 and 22.5%) compared to either Kano (9.345 and 5.27%) or Yobe (12.73 and12.135%) states. Weed density, weed cover scores as well as fresh and dry weight of weed samples from Kano were observed to be higher than the other two states. Morphological characteristics of Typha spp found in Kano State were taller with more leaves than the other two states. The study suggested that there is strong need to start an Integrated Typha management in the study areas.