Attività allelopatica in vitro della gommoresina di asafoetida sull’antagonismo di Trichoderma harzianum nei confronti dei Pleuroti delle Apiaceae.

Apiaceae oyster mushrooms (Pleurotus species) are well known for producing fruit bodies with excellent organoleptic qualities. Its cultivation is subject to contamination by several microorganisms during cultivation. Trichoderma harzianum, a filamentous fungus, is an antagonist that can cause extensive losses in Pleurotus spp. cultivation. The aim of the present work was to evaluate in vitro allelopathic activity of asafoetida oleogum-resin on the bio-control of T harzianum. Using the macrodiluition technique, asafoetida oleogum-resin was assayed for inhibitory activity against three strains of Pleurotus species, and pathogenic fungus T harzianum. The allelopathic activity of the asafoetida oleogum-resin was investigated in dual culture experiments on an agar-based medium in which different concentrations of oleogum-resin were incorporated. The results of the mycelial growth inhibition percentage of asafoetida oleogum-resin against T harzianum and Pleurotus spp., has shown that at the lowest experimental concentration levels (1,25 and 2,5 µg/ml), asafoetida oleogum-resin had a specific antifungal effect on the growth of T. harzianum mycelium and was stimulating the mycelial growth in Pleurotus species. In vitro antagonistic activity of T. harzianum against Pleurotus spp. mainly comprised four type of interactions between colonies. In the presence of the oleogumresin, all strains of T. harzianum appeared to be moderately active (1,25 µg/ml of oleogum-resin) or slightly active (2,5 µg/ml of oleogum-resin) against the Pleurotus species that either completely or partially replaced T. harzianum. In conciusion, lower concentrations of asafoetida oleogum-resin, corresponding to the allelopathic concentrations tested, could be used to control proliferation of green mould that is now being treated with other sanitizing agents.