The Effect of Bio-agent Duotaibao on Trichoderma Enrichment in Tobabcco Field Soil

Purpose In present research, the field soil treated with different dosages of Duotaibao during tobacco growth period was sampled for this bio-agent' effect on Trichoderma spp. population dynamic evaluation.Methods By using Trichoderma selective medium and the dilution plate method, the Trichoderma spp. colony was counted at dilution ratio 1.0×10-2 and 1.0×10-3 levels, and eventually the effect of Duotaibao on Trichoderma population dynamic was evaluated.Results All application of different dosage had a positive effect on the growth of Trichoderma spp., and the treatment D(300 g/m2)obtained the highest number of Trichoderma spp.72.2×102 and 72.4×103 with the increase rates of 77.8% and 126.25%,compared with CK. Further analysis showed that Trichoderma spp. population showed greatly seasonal fluctuation. E.g it achieved the highest number of Trichoderma colony with 98×103 and 95×103 in July and August,respectively, however, it only got 49×103 and 53×103 in May and September.Conclusion Based on our research work, it is reasonable that application of Duotaibao with dosage of 300 g/m2 is optimal for Trichoderma spp. population enhancement.