Trichoderma harzianum

This study investigated the shelf life and viability of Trichoderma harzianum formulated with various carrier combinations to enhance its potential as a sustainable biocontrol agent. Formulations were prepared using different ratios of corn cob and spent mushroom substrate (4:1 and 1:1) respectively, combined with clay and cassava starch. The viability of T. harzianum spores was monitored monthly over a five-month storage period under room temperature conditions (15–35 °C) by determining colony-forming units (CFU/g) on potato dextrose agar. The experiment was subjected to Completely Randomized Design (CRD) and data was analyzed using Analysis of Variance (ANOVA) at a 5% significance level. Results revealed that the media type had a highly significant effect (p< 0.001) on spore viability across all months, while concentration and substrate × concentration were non-significant. The formulation containing a 1:1 mixture of corn cob and spent mushroom substrate supplemented with clay and cassava starch consistently produced the highest CFU/g values throughout the storage period, indicating superior shelf stability. onversely, formulations with higher corn cob ratios (4:1) showed reduced viability. Overall, the inclusion of starch improved moisture retention and nutrient availability, slowing the decline in spore viability over time. The study concludes that a balanced organic–inorganic matrix enriched with starch provides an optimal carrier system for maintaining the viability of T. harzianum during storage, thereby enhancing its suitability for large-scale biocontrol applications.