Isolation and in-vitro assessment of antagonistic activity of Trichoderma spp. against Magnaporthe oryzae Longorola strain causing rice blast disease in Mali

Pyricularia oryzea (Magnaporthe oryzae) causes blast diseases in rice (Oryza sativa) in Mali. The losses could reach 90% of production during rainy weather conditions. Isolation and characterization of M. oryzae and Trichoderma species were carried out to assess the importance and distribution of the pathogen and antagonist Trichoderma species in rice fields in Sikasso (Mali), and select, in vitro, Trichoderma species with high pathogen biocontrol activity. In the pathogen isolation, only one isolate of M. oryzae were obtained, while 12 Trichoderma isolates were obtained. In the fungal growth tests three isolates of Trichoderma: Trichoderma harzianum S31, T. harzianum S32, and T. harzianum S33 highly inhibited the growth of the pathogen with a coefficient of antagonism of 0.55, 0.71 and 0.78 respectively. These isolates were selected for further greenhouse and field tests.