Isolation of Tomato Fruits Mycoflora and Evaluation in vitro and in vivo by Trichoderma harzianum

The present investigation aimed is to isolate and identify the mycetes accompanying the tomato fruits (Lycopersicon esculentum), and to evaluate in vitro and in vivo the ability of T.harzianum to control the isolated mycetes. Some infected tomato fruits by mycetes were brought from Oum-elbouaghi market. The results of isolation allowed the identification of Stemphylium sp. and Aspergillus niger. One isolate of T.harzianum / Hypocrea lixii was utilized in this study. The results of direct confrontation (in vitro) of T.harzianum against Stemphylium sp. and A.niger on PDA medium indicated the inhibition of mycelium growth in variable degrees; it was equal in the fourth day of the experiment to 54.54 % and 52.17% for Stemphylium sp. and A.niger respectively. However, it did not show any growth of the tested fungus when re-planting a disk from the interaction hyphal area between T.harzianum and Stemphylium sp. or A.niger from dual cultures, while T.harzianum grew alone in the plates. The microscopic observations of mycelia of dual culture in slide methods showed that the mycelia of T.harzianum induced degradation and aggregated the spores and analyzed the mycelia of A.niger , overgrowing the mycelia of Stemphylium sp and coiled around of them and degrading them. In vivo screening showed after 10 days of incubation an antagonistic activity of T.harzianum against the tested fungus on tomato fruits, with inhibition equal to 100 % and 95% in Stemphylium sp. and in A.niger respectively, compared with controls. Beside we found that the treated fruits with T.harzianum stayed saints as compared with control, when Stemphylium and A.niger soft rot infected all surface the test fruits. This strain of T.harzianum may offer potential for biological control of tomato Stemphylium and A.niger soft rot.