Applied Biological Research

The antagonistic activities of 11 indigenous fungal isolates belonging to 9 species were evaluated in vitro and three effective ones under in vivo against mulberry root rot pathogen Fusarium oxysporum. In vitro evaluation was done by agar plug, dual culture and food poisoning techniques. In agar plug method, Trichoderma viride isolates M and A caused maximum inhibition in pathogenic growth followed by T. harzianum. All the four isolates of Trichoderma proved highly antagonistic in dual culture, whereas Chaetomium indicum was antagonist, Trichothecium roseum moderately antagonist and Scopulariopsis brevicaulis non-antagonist. Maximum inhibition in mycelial growth (54.9%), sporulation (85.2%), spore germination (89.5%) over control (F. oxysporum) was observed due to the culture filtrate of Trichothecium roseum. The mechanism of antagonism was either hyper-parasitism or competition or antibiosis. All the three biocontrol agents evaluated in vivo significantly reduced root rot incidence and severity as compared to control, 8 and 20 months after inoculation. The disease incidence and severity in different treatments after 8 months ranged from 10 to 40 and 5.3 to 26.3%, respectively, whereas after 20 months it varied from 16.7 to 56.7 and 12.0 to 31.7%, respectively. T. viride recorded minimum disease incidence and severity. Biocontrol agents positively influenced plant height, number of leaves plant⁻¹ and above- and under-ground plant biomass.