In vitro bio-activity of three potential antagonistic fungi against selected plant pathogens in Ghana

Abstract

In the quest of developing sustainable strategies for the management of diseases affecting major crop species, this study screened three antagonists, viz. Trichoderma asperellum., Penicillium citrinum. and Myxotrichum stipitatum., for inhibitory activity against seven plant pathogens, viz. Pestalotia heterocornis, Curvularia eragrostidis, Lasiodiplodia theobromae, Sclerotium rolfsii, Colletotrichum gloeosporioides, Aspergillus flavus, and A. parasiticus on Potato Dextrose Agar (PDA) plates using the dual culture method. For each potential antagonistic fungus-pathogen combination, four replicated dual culture plates were prepared and laid out in a completely randomized design (CRD). Control plates with only the pathogens and no antagonistic fungi were also established. All assay plates were incubated at 28 (approx.) and the diameters of the pathogen in both the dual culture and control plates were measured at 6, 10 and 14 days. Percentage inhibition of fungal pathogens were calculated and used to draw a colony reduction curve for each antagonist-pathogen interaction. Areas Under the Colony Reduction Curves (AUCRCs) were calculated. Of the three antagonistic fungi tested, Trichoderma asperellum. was the most effective in inhibiting colony diameters of all seven pathogens with an average AUCRC of 813.19 % days, followed by the Penicillium citrinum. (519.25 % days). The weakest antagonist was Myxotrichum stipitatum sp. with an AUCRC of 440.6. % days. The results of the study suggest that T. asperellum and P. citrinum could be exploited for plant disease biocontrol.