EVALUATION OF INTEGRATED STRIGA HERMONTHICA CONTROL TECHNOLOGIES UNDER FARMER MANAGEMENT

Abstract

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

Conventional and biotechnological approaches for control of parasitic weeds

“…A wide range of rotations can be effective in reducing Striga numbers and increasing yields in a subsequent cereal crop (Odhiambo and Ransom 1994;Sauerborn et al 2000;Oswald and Ransom 2001;Schulz et al 2003;Ahonsi et al 2004;Hess and Dodo 2004). However, catch (parasite-susceptible) cropping is rarely used by small farmers to control Striga because the technique is not well known and should be adapted to a specific cropping system (Oswald et al 1999).…”

Participatory appraisal of institutional and political constraints and opportunities for innovation to address parasitic weeds in rice

“…The institutional and political dimensions of parasitic weeds and innovations to address them do not receive structural attention. While farmers frequently participate in parasitic weeds research on rice and other crops (Abang et al, 2007;Emechebe et al, 2004;Kamara et al, 2008;Schulz et al, 2003), above-farm level actors such as the private sector, civil society organisations, and government are less often involved. The objective of this paper is to identify institutional and political constraints and opportunities for innovation to address parasitic weed problems in rice as perceived by different stakeholder groups.…”

Contending with Complexity: The Role of Evaluation in Implementing Sustainable Natural Resource Management

“…In 1999, 19 farmers volunteered to establish experimental plots. An extra village and another 41 farmers joined the work in 2000 (Schulz et al, 2003).…”