Striga research in Ethiopia: achievements and future prospects

Most of the damaging spedies of Striga hermonthica, Striga asiatica, S. latericia, S. asper, S. gesnerioides, and S. forbesii are known to occur in Ethiopia. Among those, Striga hermonthica is the most wide spread and devastating, attacking important food crops such as sorghum, maize, and finger millet. More recently, it is becoming increasing important on tef, Eragrostis tef trouter, the main staple cereal food crop in the country. A large number of sorghum genotypes both indigenous and introduced were evaluated by the programme. Varieties that have showed relatively consistent and high level of resistance were SAR-24, ICSV-1007, ICSV-1006, N-13, Framida and SRN-39. Work on identifying resistance sources in maize was not so successful. However, considerable variation between varieties was observed in terms of suscepibility to Striga. A promising line, b37 91-952-1 (from purdue University, USA) was found to be low stimulant producer in recent laboratory tests. Some more tropical lines from CIMMYT have also appeared to be very low haustorium factor producers. Pearl millet has so far proved immune to Ethiopian populations of Striga hermonthica. Results ofother Striga control investigations have revealed that late season hand pulling (flowering Striga) requires 2 to 4 fold less labour compared to early pulling (farmers' practice). Nitrogen has decreased infestation and the effect was more apparent on some selected improved varieties such as ICSV-1006, and ICSV-1007 and under conditons of improved moisture availability. Inter-cropping of sorghum with legume crops was found to be effective in minimizing Striga incidence and improving yield per unit area legume crops was found be effective in minimizing Striga incidence and improving yield per unit area. None of the herbicides tested could arrest subterranean development of Striga but 2,4-D, glufosinate and oxiflourfen were suitable for post emergence use to prevent seed setting. Integrated control trials have revealed that Striga can be more effectively controlled through the combined use of improved management practices involving relatively more resistant cultivars, row planting, fertilizer and hand pulling (flowering Striga) or 2,4-D (11 product/ha.). The national strategy is to develop a more holistic approach to address the complex of all associated factors with Striga. Currently, special emphasis is being given to developing cropping systems and agroforestry interventions to improve soil fertility and control Striga.