Sorghum harvested for seed fromClaviceps africana-infectedfields becomes coated with sugary disease exudates in which the fungal spores are borne. The role of exudates in the inhibition of seed germination, seedling growth and predisposition to seedling diseases was investigated.In vitrostudies showed that low exudate concentrations could reduce germination and seedling growth and that cultivars differed in their response to exudates. In the field and greenhouse, seed-borne exudate concentrations were quantified on the basis of spores g−1seed. Concentrations of 6.47 x 106spores g−1seed artificially applied to healthy seed reduced germination and seedling emergence, and predisposed seedlings to mesocotyl discoloration and post-emergence damping off. The spore concentration on seed from a naturally-infected field was 55 x 106spores g−1seed. This could be reduced by seed washing but large volumes of water were required to reduce exudate concentrations to levels which would not affect germination and seedling development.