RELATIVE ROLES OF WIND, CROP SEEDS, AND CATTLE IN DISPERSAL OF STRIGASPP

Parasitic flowering plants of the genus Striga cause extensive damage to cereal and legume crops in Africa, but factors affecting seed dispe rsal have not been well understood. Petrolatum-coated microscope slide s placed at regular intervals from Striga hermonthica plants and suspe nded at 1-, 2-, and 3-m heights from trees within and around S. hermon thica-infested fields indicated that distribution of seeds by wind was not extensive. The maximum horizontal distance that seeds were caught was 12 m and the maximum vertical distance was 2 m. Samples of local market supplies of cowpea, maize, millet, and sorghum from six areas o f Nigeria over 2 yr contained an average of 20.9, 32.4, 24.2, and 27.3 Striga seeds, respectively. Cattle dung was sampled intensively for p arasite seeds in and around two S. hermonthica-infested fields and fro m 45 locations (88 fields) in S. hermonthica-infested areas of Nigeria . Cattle dung was of minor importance in seed dispersal. Implications of dispersal mechanisms in control are discussed.