Trichoderma atroviride SC1 is a good wound colonizer and can protect grapevine from infections of Phaeoacremonium aleophilum and Phaeomoniella chlamydospora in nurseries and vineyards

Phaeoacremonium aleophilum (Pal) and Phaeomoniella chlamydospora (Pch) are two of the most important species associated with Esca disease in grapevines. They are frequently isolated from vines showing symptoms of Esca disease in different countries. Plant colonization by these two microorganisms is supposed to take place from wounds. Therefore wound protection during all stages of grapevine propagation and in established vineyards is of extreme importance to prevent infection by these Esca-associated microorganisms. However, products containing either chemicals or biocontrol agents as Trichoderma harzianum and T. atroviride gave inconsistent results so far. The main reason for failure is most probably the short protection time of wounds. The strain T. atroviride SC1 was isolated from decayed wood, it has an outstanding capacity of colonizing wounds and it is a strong producer of hydrolytic enzymes. We evaluated the capability of colonizing wounds and the efficacy of preventing Pal and Pch infections either under natural infections and artificial inoculation in established vines. T. atroviride SC1 is able to colonize wounds for several months after application and to protect plants along the growing season. When applied in the nursery process it successfully colonizes almost all parts of the plants (rootstocks and scions) , fully controls infections by Pal and Pch during grafting and the level of colonization is stable during the entire process, thus giving a percentage of colonization of plants close to 100% at the time of commercialization The trials were carried out for three years in several sites in Italy and France indicating a good adaptability to different environmental conditions and consistency of results. T. atroviride SC1 may represent an interesting strain for further developments in the protection of grapevine wounds from Esca-associated microorganisms.