Antagonistic potential of Trichoderma spp. evaluated under in vitro and in vivo conditions against Alternaria spp. responsible for early blight of tomato in Algeria

In recent years, many studies have shown that Alternaria early blight bio control became an alternative strategy to protect a wide range of economically important crops. Among the most damaging diseases of tomato in Algeria, three species have been identified as: Alternaria solani, A. linariae and A. grandi and considered among major constraint. As a control approach, this research was carried out to assess antagonistic activity of Trichoderma atroviride and T. asperellum against these three species of Alternaria genus and realised in vitro, in vivo, and greenhouse conditions. In vitro results showed that the mycelial growth of Alternaria spp. was reduced by both Trichoderma species. Under in vivo conditions, early blight symptoms were reduced to 65.9% in pre-treated plants. Results of two years of greenhouse experiments indicate that T. atroviride reduced disease severity by 64.6% and 59.7% in 2017-2018 and improved productivity by 44.2% and 44.6%. This study showed that the antagonistic activity of the two Trichoderma species has a bio-stimulant effect to protect tomato plants by enhancing its defence system and productivity.