In vitro and in vivo efficiency of Trichoderma harzianum against Rhizopus soft rot occurred on tomato fruits (Lycopersicon esculentum)

Abstract

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