Egyptian Journal of Biological Pest Control (Oct 2022)
Antifungal and growth activity of strains of Trichoderma spp. against the Avocado “tristeza” disease, Phytophthora cinnamomi
Abstract
Abstract Background Avocado “tristeza,” a disease caused by Phytophthora cinnamomi, is one of the main limiting factors of avocado production in the Caribbean region. To control the pathogen, the application of agrochemicals is required, but this has caused environmental problems. Trichoderma spp. present properties in promoting plant growth and controlling phytopathogens, being proposed as an alternative to replace chemical fertilizers. The objective of the study was to evaluate the antagonistic activity of Trichoderma spp. against P. cinnamomi and its possible potential for promoting plant growth in vitro. Soil samples were taken from avocado cultivars from the municipalities of Ovejas (Sucre-Colombia) and Chalán (Sucre-Colombia). Results Serial dilutions were carried out for the isolation of Trichoderma spp. Once the strains were purified, the antagonism test against P. cinnamomi was carried out in PDA culture medium. For growth promotion, SRS medium was used for phosphate solubilization and CAS medium for siderophore production. DNA extraction and identification of the isolates were performed using the tef1 gene. Trichoderma harzianum and T. asperellum presented a 93.4% inhibition against the pathogen, followed by T. viride with an inhibition of 83.5% and finally T. longibrachiatum with 78.4% inhibition, showing significant differences in the control of the growth of the pathogen (p < 0.05) and promoted plant growth. These species release enzymes that can degrade the cell wall of the pathogen causing its death or inhibit its growth through the production of secondary metabolites. Conclusions The results showed that the application of Trichoderma spp. in crops confers protection against pathogens and stimulates the growth of plants to obtain a high yield.
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