Demand-Driven Technologies for Sustainable Maize ... - IITA

eduction or absence of rotation and bush fallow, has exacerbated landdegradation and Striga infestation in the sub-region. Striga infestationis associated with low soil fertility, continuous monocropping, increasedland use intensifi cation, and poor weed management (Ransom 1999).Sauerborn (1991) reported that 21 million ha of land wereinfested with Striga in Africa, while estimates obtained by Lagoke etal. (1991) showed that about 50 million out of the 73 million ha ofarable cropland in Africa were already severely or moderately infested.The extent of infestation of the savanna ecologies in Nigeria may behigher as shown by Lagoke et al. (1991) who reported infestation ofover 40% of the arable land by several Striga species. They furtherforecast infestation of another 40% during the 10 subsequent years,bringing the level of infestation to 80% by 2001. Crop losses rangingbetween 10 and 100% due to the menace of the parasitic weeds havebeen reported (Lagoke et. al. 1991). Striga impairs photosyntheticeffi ciency (Stewart et al. 1991) and exerts phytotoxic effects (Ransomet al. 1996) on the host.Striga infestation and host damage are usually more severe underabiotic stresses. Manyong et al. (1996) reported that S. hermonthica(Del.) Benth had become a serious problem in areas of poor marketaccess where farmers do not apply fertilizer adequately to maize innorthern Guinea savanna of Nigeria. Emechebe et al. (1991) alsoreported that S. gesnerioides (Willd.) Vatke completely blighted cowpea[Vigna unguiculata (L.) Walp] on farmers’ fi elds in the northern Guineasavanna, resulting in crop losses as high as 100%.The problem of Striga infestation is sometimes compounded by theoccurrence of more than one species on the same farmland and especiallyin cereal-legume intercrops. In a study conducted by the PromotingSustainable Agriculture in Borno State (PROSAB) Project, farmers ratedStriga infestation as the most important constraint together with lowsoil fertility during a community livelihood analysis in the study area(PROSAB 2004). However, no empirical study has been conducted todetermine the level or extent of infestation in the study area apart frompreliminary reports made by Gworgwor et al. (2001). They reportedthat 98% of the fi elds sampled in the northeast region of Nigeria wereinfested with Striga hermonthica while Striga densifl ora was a minorspecies in the zone. Ogborn (1987) reported that Striga infestation infarmers’ fi elds varied according to farming practices such as rotations,manure and/or fertilizer application, and weed management.Soil type, fi eld management, distance of farms from settlementsand rainfall regime may also infl uence the extent of Striga infestation.The present study was conducted to determine the level and extentof infestation of crop and fallow fi elds by Striga species in thePROSAB area. Information obtained from the study would serve as273