The effect of 1.5% v/v Ca-lignosulphonate (Ca-Ls) amendment to two different organic substrates on the viability of Sclerotinia sclerotiorum sclerotia was investigated. Sclerotia were buried in Ca-Ls amended substrates for 30 days. Non amended substrates and sterile sand were used as controls. The viability of sclerotia recovered from organic substrates was reduced by 50-42% compared to controls. The Ca-Ls enhanced the activity of the indigenous mycoparasitic fungi Fusarium oxysporum, Mucor spp and Trichoderma spp. Therefore the biocontrol ability of Ca-Ls against sclerotia was due to the stimulation of microbial activity and therefore it is strictly dependent on the microbial composition of the substrate
