• biocontrol
• biostimolant
• peat
• substrates
• Trichoderma

Trichoderma spp. are free-living fungi commonly widespread in soil and root ecosystems. Recent discoveries show them as opportunistic, avirulent plant symbionts as well as parasites of other fungi. Some strains establish robust and long-lasting colonization of roots by entering into the first epidermal layers. Root colonization frequently results in enhancing of growth and development, crop productivity or induction of resistance to abiotic and biotic factors.
Peat, mainly imported from the northern and eastern European regions, is the basic constituent of organic substrates commonly utilized in the cultivation of ornamental plants in pots or in benches. During the past few years, the supply of the peat is hampered by environmental and economical constraints. Recently, the European Commission decided to exclude all substrates containing peat from the release of the Community Eco-Label Mark. In this optic the need to reduce peat in ornamental substrates devised great attention and resulted in pressing and increasing research activity to set up new and innovative substrates for ornamental market.
The aim of the present PhD thesis is to select beneficial fungi belonging to Trichoderma genus, to be add as soil inoculants, in order to develop an innovative, economical and suitable substrate alternative to peat for cultivation of seed plants (Limonium sinuatum and Cupressus sempervirens) and of acidophilus species (Camellia japonica) of ornamental interest. The activity involved the selection of Trichoderma spp. isolates for their ability to grow in the roots, as endophytes, or in the rhizosphere, to protect plants against plant pathogens or to act as plant growth promoters. The preliminary screening for endophytism resulted in 10 interesting isolates (out of 162) for Limonium sinuatum, 9 (out of 162) for Cupressus sempervirens and 8 (out of 202) for Camellia japonica. From following rounds of screening, three Trichoderma isolates, among which T. asperellum 2046 in common for all the species, confirmed the best endophytic performance and improved growth.
The antagonistic activity of these selected strains, against fungal plant pathogens as Sclerotinia sclerotiorum, S. minor, Colletotrichum gleospoiroides and Rhizoctonia solani, has been evaluated in order to analyse if these isolates could be considered good beneficial fungi. In addition. T2046 was evaluated in biocontrol experiments on Limonium, against S. sclerotiorum and S. minor with mycoparasistim investigated as principal mechanisms.
Encouraging results herewith obtained, suggest that T. asperellum 2046 could be taken into account as bioactive ingredient of new biopesticide and/or biofertilizer to be used as inoculant for innovative substrates for ornamental plants.