Reduction of frosty pod rot severity in Theobroma cacao CCN51 by indigenous Trichoderma-based bioformulations under controlled conditions

Cacao is of significant socio-cultural and economic importance for Peru. However, it is highly susceptible to phytopathogens, such as Moniliophthora roreri , the causal agent of frosty pod rot. This disease is well known for its significant impact on the quality and yield of cacao beans. In response to the necessity of environmentally friendly alternatives for cacao management, the use of bioformulations based on native microorganisms naturally adapted to Peruvian cacao agroecosystems is proposed. In this study, native Trichoderma afroharzianum CP24-6, Trichoderma BIF7-C3, Trichoderma UCF18-M1, and Trichoderma UCPF4-C3, isolated from cacao rhizosphere in the Amazonas region, were selected to evaluate their potential to protect cacao crop from M. roreri infection. These strains were tested under in vitro conditions, achieving up to 100 % inhibition of the phytopathogen growth. The strains were then used as active ingredients in bioformulations prepared with two substrates, rice and rice husk. The results suggested an influence on spore production, CFU/g, purity and germination quality parameters. Moreover, under field controlled conditions, the bioformulations exhibited variable effects on disease severity. Notably, the application of strains CP24-6 and BIF7-C3, using rice as the fermentative substrate, significantly reduced both external and internal severity by over 40 %, respectively. These findings highlight the critical roles of both substrate and strain selection in bioformulation efficacy and suggest the potential of these natives strain-based bioformulation for managing cacao moniliasis.