## 3 Results and Discussion
### Antifungal Activity against Plant Pathogenic Fungi  
Various pathogenic fungi infect plants leading to the reduction in yield and quality crop, and the contamination of grains with fungal mycotoxins. Therefore, we have evaluated the antifungal activities of S1, S2, S3 and S4 against five fungal plant pathogens namely _F. oxysporum, F. culmorum, F. graminearum, Alternaria alternata_ and _Aspergillus niger_. As shown in Table 2, the antifungal test demonstrated that pomegranate peel (S1) produced antifungal compounds against a variety of phytopathogenic fungi from different classes. A moderate but significant (\(p<0.05\)) inhibitory effect of S1 on the growth of _Aspergillus niger_ CTM 1009 with an inhibition zone of 14 mm was observed. In 2009, [PERSON] [44] reported that several fungal species, such as _Aspergillus niger_, were sensitive to pomegranate fruit peel water/methanol extract, however, the inhibitory effect of pomegranate water extracts have not been studied against this fungi. In earlier studies, [PERSON] and [PERSON] [45] in 1982 reported that pomegranate peel extract have no effect on the growth of _Aspergillus flavus_ and _Aspergillus parasiticus_. More recently, [PERSON] et al. [46] reported in 2017 that aqueous extract of pomegranate peel showed a wide spectrum of antifungal activities especially against _Fusarium oxysporum_. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline \multirow{2}{*}{**Fungal Strains**} & \multicolumn{5}{c}{**Inhibition Zones Diameters (mm)**} \\ \cline{2-6}  & **S1** & **S2** & **S3** & **S4** & **Amphotericin B** \\ \hline _Fusarium oxysporum_ & \multirow{2}{*}{12.25 \(\pm\) 0.25 dB  & 22.25 \(\pm\) 0.50 dB  & 14.25 \(\pm\) 0.25 b  } & 15.00 \(\pm\) 0.33 b  & 15.00 \(\pm\) 0.33 c  \\ (ISPAVE 21w) & & & & & \\ \hline _Fusarium graminearum_ & \multirow{2}{*}{11.75 \(\pm\) 0.33 a  & 24.75 \(\pm\) 0.33 d  & 14.75 \(\pm\) 0.50 c  } & 11.25 \(\pm\) 0.66 b  & 14.75 \(\pm\) 0.38 ab  \\ (CTM 10230) & & & & & \\ \hline S1 (pomegranate peel), S2 (_Spirulina_), S3 (pomegranate peel–_Spirulina_: 25%/75%) and S4 (pomegranate peel–_Spirulina_: 50%/50%). \(\pm\): standard deviation of the mean; inhibition zones diameters (mm) with a different letter (a–d) of the same fungal strain are significantly different (\(p<0.05\)); Inhibition zones diameters (mm) with a different letter (A–C) of the same extract are significantly different.[ENDFOOTNOTE] & 14.75 \(\pm\) 0.66 b  & 19.25 \(\pm\) 0.83 c  & 14.75 \(\pm\) 0.66 b [FOOTNOTE:]Footnote : footnotemark: [ENDFOOTNOTE] \\ (CTM 10230) & & & & & \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Antifungal activity of of _Spirulina platensis_ and its combinations with pomegranate peel against plant pathogenic fungi: _Fusarium oxysporum_, _Fusarium culmorum_, _Fusarium graminearum_, _Aspergillus niger_ and _Alternaria alternata_ strains. Equally, as illustrated in the Table 2, we have demonstrated the capacity of _Spirulina_ (S2) to inhibit all the studied panel of fungal strains, particularly _Fusarium_ genus. In fact, this antifungal activity was similar to standard synthetic antifungal agent (Amphotericin B). Similarly, [PERSON] [47], reported the inhibition growth of _Fusarium oxysporum_ followed by _Aspergillus flavus_ and _Aspergillus niger_ by _Spirulina platensis_ organic extract. Furthermore, [PERSON] et al. in 2011 reported the inhibitory effect of hexane and methanolic extracts of _Spirulina platensis_ against _Aspergillus_ spp. [48]. The activity of the alga could be due to the intracellular and extracellular metabolites that have antifungal properties [47]. In general, it was demonstrated that the most antifungal compounds in _Spirulina_ are mainly polyphenols along with polysaccharides that inhibit microbial growth, or directly by destroying the living structures of fungi [49]. Compared to S1, S2 and S4, Amphbotericin B had higher antifungal activity against _Aspergillus niger_ CTM 10099 and _Alternaria alternata_ CTM 10230.