Biocontrol of Trichoderma isolates against Phytopthora infestans and evaluating the growth of tomatoes (lycopersicon esculentum)

Abstract

Tomato (lycopersicon esculentum) is one of the most important vegetable crops belongs to the family solanaceae ranking 8th in annual national production in Ethiopia. In spite of this, major pests like, Phytopthora infestans, affect the production of tomatoes around the world. To achieve profitable yields economically, producers intensify chemical treatments to control plant diseases but indicate health risks to the consumers. As result, application of biological antagonists against tomatoes disease reduces incidence and severity of the pathogen. Therefore, the aim of the study is to assess the antagonistic potential of isolates of Trichoderma against the Phytopthora infestans on the growth and yield of tomato plants. The 40 diseased plants samples were collected from Dedo and Goma districts and analyzed in Jimma university. All the data were subjected to one-way ANOVA at p ≤ 0.05. From 36 isolates, 18 were identified to be Phytopthora infestans and from 103 isolates obtained from soil, 10 were Trichoderma spp. In dual culture assay, the 3 days percentage of inhibition of pathogen by Trichoderma-Ju-TGDa-2, Ju-TGDb-3, Ju-TDWc-2 and Ju-TGDb-2 varied from 10.2 to 15%, 38% to 43.4% in 6 days and increased to 58 to 61.4% in 9 days. The non-volatile compounds of Trichoderma-Ju-TGDb-3, JuTDWc-2, Ju-TGDa-2, Ju-TGDb-2 and Ju-TGDb-1 inhibited with 63.9%, 60.9%, 57.7%, 44.4% and 24%, respectively. The volatile compounds of the Trichoderma-Ju-TGDb-2, Ju-TDWc-2, JuTGDb-3 and Ju-TGDa-2 inhibition varied between 42.5 to 2.5 in 3 days, 63.5 to 34.7% in 5 days and 64.1 to 35.8% in 6 days. In greenhouse, the shoot length, root length, fresh and dry weights and yields of tomato plants were 78.7 cm, 28.21 cm, 104.11 g, 28.44 g, 15.96 g respectively. It is concluded that the Trichoderma isolates Ju-TGDa-2, Ju-TGDb-3 and Ju-TDWc-2 are the most promising biocontrol agent against the late blight as well as enhance the growth and reduce the relative percent yield loss of tomato plants. It should be recommended that the potential isolates should be further evaluated for their safety and the protocol of administration need to be developed for field application by smallholder farmers.