In vitro antagonist activity of cedar Trichoderma species against three cedarwood lignivorous fungi

Cedarwood lignivorous fungi cause significant damage to cedar groves. In Morocco, the losses of cedar wood are estimated at more than 30% due to these fungi, which cause two primary diseases known as M'jej and Saboune. In this study, we are interested in the isolation and molecular identification of parasitic fungi and trichoderma species in the cedar groves of Tazekka National Park and Azrou forest, as well as the biological control of these lignivorous fungi by Trichoderma species. The molecular characterization identified three phytopathogenic fungi: Paecilomyces maximus, Pleurostoma richardsiae, and Alternaria tenuissima. Under in vitro conditions, Trichoderma species (Trichoderma lixii, Trichoderma simmonsii, and Trichoderma viridescens) were more effective. They significantly inhibited the mycelial growth of the studied pathogens through the production of volatile metabolites and mycoparasitic capacity. A maximum percentage exceeding 73 % was recorded. In addition, the direct confrontation tests showed a great capacity of Trichoderma isolates to colonize the medium in competition with the pathogenic fungi, with colonization percentages that reached 81.25 %. In general, Trichoderma agents significantly inhibited the growth of pathogens through various inhibition mechanisms, including colonization of the space, mycoparasitism, or the production of volatile or diffusible metabolites. An in-vivo study is recommended to take advantage of this ecological biocontrol solution.