Cultural control measures to diminish sorghum yield loss and parasite success under Striga hermonthica infestation

Prospects of reducing Striga hermonthica (Del.) Benth. parasitism by means of cultural control measures were assessed. In a pot experiment, deep planting, the use of transplants and shallow soil-tillage, strongly delayed and reduced Striga infection of a sensitive and a tolerant sorghum cultivar. Application of all three measures combined resulted in a four-week delay in first emergence of the parasite, a reduced number of emerged Striga plants and a decimation of Striga dry weight. With the sensitive cultivar CK-60B a yield loss of 92% was reduced to 26%, whereas with the tolerant cultivar Tiemarifing application of the cultural control measures completely cancelled out a yield loss of 28%. Evaluation of these cultural measures under field conditions in Mali resulted in a strong reduction in Striga-infection level (85%). At the same time, the measures did not result in delayed first emergence of the parasite and had no beneficial effect on crop yield. It was argued that the presence of a natural Striga soil seed bank, with seeds throughout the tilth, might be an important reason for the reduced effectiveness of the proposed cultural control measures under field conditions.