Abstract

The potato (Solanum tuberosum L.) is a tuberous herbaceous plant that belongs to the Solanaceae family. Several biotic and abiotic factors affecting its production include fungi such as mildew. In this present work, we proposed to evaluate the antagonistic power of Trichoderma viride against parasite Phytophthora infestans of potato tubers. We conducted two tests; for the first, in confrontation in-vitro, the direct confrontation was performed on an agar PDA medium to demonstrate the inhibitory capacity of T. viride on P. infestans. For the second test, in- vivo confrontation, we realized two methods; the first was carried out using a mycelia disk on the antagonist and the second was done by injecting the spore solution of T. viride into the potato tubers after this pathogen was applied. The results of the in- vitro test revealed that the confrontation between T. viride and the P. infestans showed the inhibitory capacity of T. viride, be it directly (68%) or remotely (58%) on the growth medium. Interesting results were also obtained in- vivo. The injection of the tubercles with a T. viride spore solution reduced the development of P. infestans with an average penetration of 3.28 mm for the T. viride and of 1.65 mm for the P. infestans. The findings of the mycelia discs method were similar to the injection method with a penetration average of 2.62 mm for T. viride and 1.81 mm for P. infestans. The test results in -vitro showed the efficiency of T. viride against P. infestans; while for in-vivo, it was proved that this antagonist possesses a very significant inhibitory effect that suppresses the spread of the pathogen.

Keywords: Biological control, pathogen, confrontation, symptoms, in vivo, in vitro.