Identification of native soil-derived Trichoderma spp. isolates and analysis of their antagonist traits against Lasiodiplodia theobromae causing stem-end rot in papaya

The aim of the present research was to identify and analyse the biocontrol capacity of nine local Trichoderma spp. isolates against Lasiodiplodia theobromae. The isolates were identified as T. asperellum (3), T. harzianum (5) and T. koningiospsis (1). These fungi significantly slowed L. theobromae mycelial development in vitro, with maximum reductions of 75.4 and 64.1% reported with T. asperellum BRS-1 and T. harzianum BRS-7, respectively. The antagonistic fungi were able to inhibit the growth of L. theobromae through the production of mycotoxic compounds. After 5 days of incubation, the fungi produced a large number of conidia and targeted lytic enzymes in solid-state fermentation (SSF). The principal component analysis (PCA) clustered Trichoderma strains according to their phylogenetical relationships and demonstrated a tight association between the species sub-group and antagonistic features. These findings suggest that local soil-derived Trichoderma spp. have the potential to be efficient biological agents against L. theobromae.