Marmande seedlings caused by R. Solani. Experimentswere carried out in both sterilized and non-sterilized soils, wherefour treatments were performed: (1) positive control by sowinguncoated tomato seeds in non-infested soils; (2) negative control bysowing uncoated tomato seeds in infested soils to evaluate the vari-etal sensitivity; (3) sowing coated tomato seeds in infested soils toevaluate the biocontrol capacity of each antagonistic isolate againstR. solani damping-off; (4) use of a chemical agent, thioperoxydi-carbonic diamide, tetramethylthiram (TMTD), to control R. solanidamping-off. In the last case, sterilized seeds were treated as rec-ommended by the manufacturer (thorough mixing, for 3 min, of10 g of the surface-sterilized tomato seeds in 0.08 g of chemicalcontrol agent wetted with 10 ml of distilled water and drying for2 h under a laminar flow hood), before being cultivated in infestedsoils.