Solid-state fermentation in an earthen vessel: Trichoderma viride spore-based biopesticide production using corn cobs

Area of Science:

• Agricultural Microbiology
• Biotechnology
• Plant Pathology

Background:

• Plant diseases caused by fungal pathogens like Rhizoctonia solani lead to significant crop losses.
• Developing sustainable and effective biopesticides is crucial for integrated pest management and reducing reliance on synthetic chemicals.
• Trichoderma viride is a well-known biocontrol agent with potential for large-scale biopesticide production.

Purpose of the Study:

• To develop a simple and robust method for producing Trichoderma viride spores using corn cobs as a substrate.
• To characterize the secondary metabolites of the produced biopesticide and evaluate its antimicrobial and plant growth-promoting activities.
• To assess the storage viability of the biopesticide for potential farm deployment.

Main Methods:

• Production of Trichoderma viride spores in an earthen vessel using 4 kg of corn cobs over 21 days.
• Gas chromatography-mass spectrometry (GC-MS) analysis of the ethyl acetate extract to identify secondary metabolites.
• Determination of minimum fungicidal concentration (MFC) against Rhizoctonia solani.
• Plate assays and pot experiments on Rhizoctonia solani-infected potato plants.
• Storage viability assessment at 30 ± 2 °C for 10 months.

Main Results:

• Maximum spore count achieved was 2.50 × 10^9 spores/g of substrate with a significant moisture reduction.
• GC-MS analysis identified 20 secondary metabolites, including 13 antimicrobial compounds and one plant growth-promoting compound.
• The biopesticide exhibited a minimum fungicidal concentration of 5-10 mg/ml against Rhizoctonia solani.
• Effective antifungal activity and plant growth promotion were observed in plate and pot experiments.
• The biopesticide maintained 71.28% viability after 10 months of storage.

Conclusions:

• A simple, cost-effective technology for producing a potent Trichoderma viride biopesticide using corn cobs has been successfully developed.
• The biopesticide possesses significant antimicrobial properties against Rhizoctonia solani and plant growth-promoting capabilities.
• The high storage viability indicates strong potential for practical application in agriculture for sustainable disease management.