Study on the effects of four medicinal plant essential oils and two Trichoderma species on biocontrol of grape fruit rot fungi

Grape, like other horticultural products due to high humidity, low relative pH and wealth of nutrients, is subjected to attack by pathogenic fungi during the harvest and storage stages. In this study, at first, the some post-harvest pathogenic fungi of grape were isolated in Meshgin-shahr and two fungal species including Botrytis cinerea and Cladosporium cladosporioides were identified as the domonant species. Aspergillus tubingensis, causal agent of fruit rot and toxigenic species on grape and raisin was selected as well. In order to evaluate their biocontrol possibility, the effects of Trichoderma harzianum T447 and T. hamatum T622 and four medicinal plant essential oils (EOs) including mentha, spearmint, fennel and yarrow were tested in vitro. Results revealed that both of anthagonistic fungi were prospering than pathogenic fungi in nutrient competition and their volatile metabolites showed the highest inhibition to C. cladosporioides. 10% filtrate culture extract of T. harzianum T447 could effectively (≥85%) prevented the fungal mycelial growth. Also, our results showed that fungal species, EO type and its concentration play a critical role (P≤0.01) in fungal mycelia inhibition. Mentha and fennel EOs were known respectively as the most effective and weakest treatments. GC-MS analysis demonstrated that piperitoneoxid and Cis piperitone oxide, L-Menthone, dimethyl-4(E),6-octadien-2-ol and trans-Anethole were the main components of the essential oils of Mentha longifolia, M. spicata, Foeniculum vulgare and Achillea sp., respectively. Due to the significant inhibition of essential oils and biocontrol fungi, additional researches about their use for grape post-harvest diseases control are recommended.