Screening and Optimization of Solid Fermentation Medium for Trichoderma viride M1M2 and Its Controlling Effect on Sclerotinia Stem Rot in Soybean

WANG Chun; WANG Qian; CAO Xu; MENG Qinglin; WANG Yu; YU Liangbin; LI Yichu

doi:10.15933/j.cnki.1004-3268.2026.05.011

Abstract：Using wheat bran,rice husk,and cracked maize as substrates,single-factor and orthogonal experiments were conducted to screen the optimal sporulation medium formulation for Trichoderma viride strain M1M2.The effects of mineral elements(Fe2+,Mg2+,Cu2+,etc.)on sporulation yield were investigated,while inoculum density,moisture content,and incubation temperature were optimized.Pot experiments were conducted to assess the biocontrol efficacy of different M1M2 spore suspension concentrations against sclerotinia stem rot in soybean,and selective media were employed to monitor colonization dynamics in soil,aiming to establish a technical foundation for M1M2 biocontrol agent development and application.The results demonstrated that strain M1M2 achieved maximum mycelial growth rate and biomass in wheat bran and cracked maize substrates.Orthogonal screening identified the optimal solid-state fermentation formula as cracked maize:rice husk:wheat bran=2:3:1,with Mg2+and Cu2+supplementation to this substrate significantly enhancing sporulation.The optimized fermentation conditions comprised inoculation with 7 mL of spore suspension at 1×106 spores/mL in 20 g substrate,water addition of 5 mL,and incubation at 28℃,yielding maximum sporulation under these parameters.Pot experiments revealed that M1M2 application concentrations≥1×107 cfu/mL provided>60％control efficacy against sclerotinia stem rot in soybean,with 1×108 cfu/mL and 1×109 cfu/mL treatments achieving 71.4％and 72.5％efficacy,respectively.Soil colonization analysis showed that M1M2 populations peaked at 6.5×106 cfu/g on day 7 post-application and remained at 2.0×105 cfu/g after 30 days—10-fold higher than the blank control.These findings indicate that cost-effective mass production of strain M1M2 can be realized through medium screening,fermentation optimization,and application technology development.The strain exhibits effective biocontrol at concentrations≥1×107cfu/mL,providing an efficient candidate and compatible application technology for biological management of sclerotinia stem rot in soybean.