Hypocrea viridescens ITV43 potential biological control agent for Moniliophthora roreri Cif& Par, Phytophthora megasperma and P. capsici

A Hypocrea/Trichoderma isolate was obtained from a sample of cocoa (Theobroma cacao L.) pod with symptoms of frosty pod rot disease from a cocoa plantation in Huimanguillo, Tabasco, Mexico. The strain was identified as Hypocrea viridescens ITV43 by its morphological characteristics and was tested against Moniliophthora roreri Cif & Par and Phytophthora strains by confrontation experiments. The biocontrol of H. viridescens ITV43 measured as Biocontrol Index (BCI) at 7 days against M. roreri (HT-ITV01, HT-ITV20, HT-ITV27), P. megasperma (HT-ITV08, HT-ITV15, HT-ITV37) and P. capsici (HT-ITV14, HT-ITV16, HT-ITV33) strains ranged from 78.28-81.63%, 63.04-69.95%, and 69.77-76.31%, respectively. After 31 days of incubation the BCI values increased to 81.52-86.50 for M. roreri and 100% for Phythopthora strains. Samples taken from the interaction zone were observed by optical and scanning electron microscopy. The results showed the effect of H. viridescens ITV43 strain on morphological deformations and disorganization of the M. roreri and Phytophthora cell walls structures. Highest BCI values obtained suggest that the Hypocrea strains isolated from T. cocoa could have the ability to antagonize more efficiently against fungal pathogens of this crop.