Plant Growth Promotion and Biocontrol of by Saline Tolerant Isolates under Salinity Stress.

This present study evaluates three isolates of Trichoderma as plant growth promoting or biological control agents: f. sp. , Trichoderma , and the marine isolate obtained from , Trichoderma The purpose is to contribute to an overall reduction in pesticide residues in the fruit and the environment and to a decrease in chemical fertilizers, the excess of which aggravates one of the most serious abiotic stresses, salinity. The tolerance of the different isolates to increasing concentrations of sodium chloride was evaluated in vitro, as well as their antagonistic capacity against Pythium ultimum. The plant growth promoting capacity and effects of strains on the severity of on melon seedlings under saline conditions were also analysed. The results reveal that the three isolates of , regardless of their origin, alleviate the stress produced by salinity, resulting in larger plants with an air-dry weight percentage above 80% in saline stress conditions for , or an increase in root-dry weight close to 50% when f. sp. was applied. Likewise, the three isolates showed antagonistic activity against , reducing the incidence of the disease, with the highest response found for . Biological control of by f. sp. and is reported for the first time, reducing disease severity by 62.96% and 51.85%, respectively. This is the first description of f. sp. as a biological control agent and growth promoter. The application of these isolates can be of enormous benefit to horticultural crops, in both seedbeds and greenhouses.