Abstract

The growth inhibition of Colletotrichum gloeosporioides isolated from cassava was studied in-vitro using Trichoderma longibrachiatum. Both fungi were cultured together on the same Petri plate using three different pairing methods. Inoculation of each fungus on separate Petri plates served as controls. For each pairing method, experiments were conducted in five replicates. Radial growth (cm) of both C. gloeosporioides and T. longibrachiatum in all Petri plates were measured daily for 7 days. In all the three pairing methods, T. longibrachiatum significantly inhibited the growth of C. gloeosporioides (P > 0.0001). Growth inhibition of C. gloeosporioides by T. longibrachiatum was better in ‘inoculating antagonist before pathogen’ than in the other two pairing methods (P = 0.05). C. gloeosporioides had significant addition of radial mycelia only between days 1 and 2, as well as days 2 and 3 after pairing (DAP) before contact was made with T. longibrachiatum. Addition of mycelia mass of C. gloeosporioides slowed down significantly by the day upon contact with T. longibrachiatum (P = 0.05, R² = 0.86). F value for day after pairing (DAP) was also highly significant (P > 0.0001). T. longibrachiatumcould thus be said to possess probable antagonistic tendency against C. gloeosporioides.

Key words: Colletotrichum gloeosporioides, Trichoderma longibrachiatum, Manihot esculenta, day after pairing, growth inhibition.