Rhamphicarpa in Uganda

Together with Prof. Julie Scholes, of the University of Sheffield, Jonne Rodenburg and Mamadou Cissoko visited Uganda to select a field site for the DFID, BBSRC and Bill & Melinda Gates funded STRIGA project and to discuss with farmers and partners from Makerere University and Africa2000. On our field trip we observed Striga infested rice in the uplands and, unexpectedly so, Rhamphicarpa infested rice in the adjacent lowlands. These parasitic weeds are urgent problems to rice farmers in the Eastern Uganda.

On Thursday 23 May we went to Namutumba District (north-east of Iganga) to check some of the Striga affected rice areas and to meet rice farmers dealing with the problem. We visited the Bukonte Mixed Farmers’ Group and Buyanga Women’s Association in Nsinze Sub-County, Bukonte Parish, Busalifu Village and the Abendowooza Ndala Group, Emberi Ekuba Mixed Group, and Ivukula Integrated Farmers’ Association in Ivukula Sub-County, Ivukula Parish, Ivukula Village.

Rainfed rice, along the upland-lowland continuum, is grown extensively in this area and presumable (based on observations) the second crop after maize. In the first village we visited (Busalifu) our attention was immediately drawn to a rain-fed lowland grown to rice that was heavily infested by Rhamphicarpa. The farmers we met here refer to Rhamphicarpa fistulosa as Kayongo and this is the same local name they have for Striga hermonthica. The name refers to ‘something that hampers (rice) growth’. Farmers also knew Striga hermonthica but indicated this was less of a problem in rice in their area. In the next village (Ivukula), about 20 km further north, we met with another 20-30 farmers. Here the farmers were familiar with both Rhamphicarpa and Striga. With a smaller group of them we visited the main nearby rice area and we found again that the lowland area (grown to rice) was heavily infested with Rhamphicarpa. In the higher parts of the upland-lowland continuum we also found Striga hermonthica on rice.

The Rhamphicarpa infested area is extensive and the infection levels are severe. It seems a very serious problem for rice farmers in Namutumba District, but as we have seen before in other locations (e.g. in southern Senegal, central Benin, southern Tanzania and central Madagascar) very few agricultural professionals are aware of the problem. The problem with Rhamphicarpa is that it is a relatively unknown species yet and therefore it is often unnoticed by extension and research (not only in Uganda). We therefore expect that the extent of the problem of Rhamphicarpa in rainfed lowland rice in sub-Saharan Africa is hugely underestimated.