4.6.2. Antifungal Assay Using Poisoned Food Method (PFM)

The poisoned food method (PFM) was used to study the antifungal activity of BBS-NiONPs using different phytopathogenic fungal pathogens (A. niger, A. alternata and F. oxysporum). All fungal pathogens were obtained from Plant Pathology Laboratory, Department of Plant Sciences, Quaid-i-Azam University, Islamabad, Pakistan [29]. These fungal pathogens were cultured using autoclaved Sabouraud dextrose agar media (SDA; Oxoid CMO147). Different doses (100, 500 and 1000 µg/mL) of prepared BBS-NiONPs solution were mixed with SDA media, shaken properly, and poured into Petri plates for solidification. A disc of 7 days old fungal culture (5 mm) was put in the middle of the media plates. The non-treated SDA media and fluconazole-treated SDA media were used as the negative and positive controls, correspondingly. After incubation for 3 days at 27 °C, the mycelial growth against various concentrations of BBS-NiONPs was measured in millimetres and the percentage of inhibition was calculated by the given formula [42].

where, FC and FN represent the average increase in fungal growth (F) in the control and each treatment (NPs).