Transplanting maize and sorghum reducesStriga hermonthicadamage

Striga hermonthica is a major threat to cereal production in western Kenya and other parts of the world. In laboratory experiments, maize and sorghum showed some resistance to late Striga attachment and parasitism. Field experiments were conducted in 1996 and 1997 in western Kenya to assess the effect of transplanting maize and sorghum, under rain-fed field conditions, on grain yield and Striga parasitism. In transplanted sorghum, Striga emergence was not reduced and sorghum failed to produce grain yield in three out of four seasons. Transplanting maize in all experiments significantly increased grain yield compared to direct seeding. The improved productivity was largely associated with less Striga attachment. Striga densities were considerably lower if maize seedlings were more than 17 d old at transplanting, with decreasing levels of Striga with increasing age of the maize seedlings. Seedlings transplanted before they were 15 d old did not reduce Striga attachment. Transplanting maize under rain-fed conditions is probably only suitable for small areas that are highly infested with Striga, due to its high labor requirements. Under these conditions, crop yield can be more than doubled. An incentive to using this method by small-scale farmers would be that the main input at risk is their own labor. However, the establishment of nurseries and the timing of the transplanting operation require a certain level of farm management that could constrain the adoption of this technique.