Relationships of Trichoderma spp. quantity in soil to reducing the damping off in tobacco seedlings

B. Gveroska

Abstract: The study was conducted to investigate the quantity of Trichoderma spp., its reducing effect on the damping off in tobacco seedling and find the most efficacious application way of biocontrol agent. Some variants of application of biocontrol agent and following applications were used. Variants with fungicide, alone or together with Trichoderma, as well as no sterilized soil and manure, were also included. There is high population density of Trichoderma spp. when it is applicated by seed and treating the soil before sowing evens the soil and manure for mulching. These variants have the best results -the smallest intensity of the damping-off in seedlings. The level of a disease control in variants with a fungicide treatment and that by Trichoderma was equal or more effective in case of Trichoderma. When the biocontrol agent is applicated after growing up the seedlings, there is a smaller amount of BCA than application before sowing. The investigations have shown that bigger Trichoderma spp. quantity has a positive effect on reducing disease intensity in tobacco seedlings caused by R. solani. The model of BCA application with sowing (by seed and treating the soil or soil and manure for mulching) and several applications during the growing period are recommended for damping- off control in tobacco seedling.

Keywords: biological control; damping off; quantity; reducing effect; Rhizoctonia solani; tobacco seedlings; Trichoderma spp.

Date published: 2019-02-20