Proliferation of Trichoderma koningii in the tomato rhizosphere and the suppression of damping-off by Sclerotium rolfsii

An isolate of Trichoderma koningii Rifai was used for the treatment of tomato seeds. Seeds were stored at 6 or 20 degree C and periodically sampled, to determine the potential of T. koningii to successfully colonize the tomato rhizosphere and inhibit Sclerotium rolfsii Sacc. damping-off. The antagonist was found to be rhizosphere competent and populations increased with seedling age. Storage conditions of tomato seeds affected the biocontrol ability of T. koningii, as well its effect on plant growth. Nevertheless, after each storage period, up to 4 months, Trichoderma-treated seed still gave significantly greater (P less than or equal to 0.05) seedling counts, height and fresh weight of plants than uncoated control seed. Significant correlations (P less than or equal to 0.05) were obtained between T. koningii rhizosphere population densities and biocontrol ability and plant growth effects.