Survival and proliferation in soil of Trichoderma koningii in alginate prills

Trichoderma koningii may act as an antagonist of several phytopathogenic fungi. The incorporation of its biomass as alginate prills with or without wheat bran and the storage temperature effects on viability were evaluated. The prills were produced by adding T. koningii (Tkp) biomass to a sodium alginate suspension and dripping into calcium chloride solution. In one of the treatments wheat bran was added. The prills were dried and stored for 1 month, 2 months, 1 year and 2 years at 5 and 25 °C. To assess viability, plastic trays filled with sterile soil were infested. The number of colony-forming units (c.f.u.) of T. koningii was evaluated after 4, 8 and 12 weeks. Wheat bran prills remained biologically active for more than 2 years when kept at 5 °C. After 12 weeks the c.f.u. number per gram was 3.7 × 10⁴. This value indicates that T. koningii might be applied to the soil as alginate prills.