Efficacy of Trichoderma harzianum against Fusarium oxysporum and Rhizoctonia solani on bean and tomato plants

Abstract

Experiments were conducted in the laboratory, greenhouse, and field at the Papua New Guinea University of Technology (PNGUT) to assess the efficacy of Trichoderma harzianum against Rhizoctonia solani and Fusarium oxysporum. The dual culture of T. harzianum with R. solani and F. oxysporum isolated from the diseased bean and tomato plants under laboratory conditions showed 60.1% and 63.3%, and 54.9% and 61.6% growth reduction for R. solani and F. oxysporum, respectively. In greenhouse fungal inoculation experiments, bean and tomato plants showed relative germination index ranging from 0.56 to 1, 0.83 to 1, and disease reduction ranging from 64.8 to 96.1, and 20.3 to 83.7%, respectively. Field experiments involved tests with T. harzianum against one pathogenic fungus or against a combination of both R. solani and F. oxysporum, applied simultaneously as the pathogenic fungi or five days before application of pathogenic fungi. The results for bean and tomato plants showed relative germination index ranging from 0.42 to 0.94, and 0.63 to 0.94, and disease reduction recorded at 63.8 to 96.1%, and 11.3 to 63.9%, respectively. The outcomes of this study will form the basis for further investigation into the potential routine use of Trichoderma spp. as biological control agents against soil-borne pathogens in PNG.