Résumé:
The present investigation aims to evaluate the in vitro and in vivo ability of T.harzianum to control the
Rhizopus soft rot, that occurred on tomato fruits (Lycopersicon esculentum). Rhizopus stolonifer was
isolated from infected tomato fruits, which were brought from Oum-elbouaghi market, and identified in
laboratory of microbiology, university of Oum-elbouaghi ( Algeria). T.harzianum / Hypocrea lixii ) was
brought from the same laboratory. The results of direct confrontation (in vitro) of T.harzianum against
R.stolonifer on PDA medium, showed that an inhibition in the mycelia growth of R.stolonifer, it was equal
in the fourth day of the experiment to 43.66 %. The microscopic observations of mycelia showed that the
mycelia of T.harzianum was capable of overgrowing and degrading R.stolonifer sporangiophores and
sporangiospores. Besides, it coiled around the sporangiophores of R.stolonifer with appressoria
structure. However, it did not show any growth of R.stolonifer when re-planting a disk from the interaction
hyphal area between T.harzianum and R.stolonifer from dual culture, while T.harzianum grew alone in the
plate. In vivo screening of T.harzianum showed an antagonistic activity against R.stolonifer on tomato
fruits with 82.86% inhibition after 7 days, however the tomato fruits stayed intact, compared with control,
where Rhizopus soft rot destroyed the tomato fruits. This strain of T.harzianum may offer potential for
biological control of tomato Rhizopus soft rot
