Promising antifungal potential of selective botanical extracts, fungicides and Trichoderma isolates against Alternaria solani.
In vitro antifungal potential of Trichoderma isolates, selective botanical extracts and fungicides against A. solani was evaluated. Trichoderma isolates, i.e. T. harzianum, T. viride and T. hamatum, were tested for their antifungal effect by dual culture technique at 48, 96, 144 and 172 hrs. T. hamatum produced the highest inhibition of A. solani in vitro, followed by T. hazianum and T. viride after 172 hrs. Methanolic leaf extracts of Elettaria cardamomum, Syzygium aromaticum, Curcuma longa and root extract of Parthenium hysterophorus showed up to 100% inhibition of A. solani, compared to control, while methanolic stem and leaf extracts of P. hysterophorus produced up to 90% inhibition of the pathogen. In vitro, six different systemic fungicides Triger 25% EC (Tebuconazole), Solex (Carbendazim 40% + Triadimefon 10%), Dew (Difenoconazole), Amistor Top SC (Azoxystrobin + Difenoconazole), Corel 25% EC (Difenoconazole), Reflex (Difenoconazole + Propiconazole) were tested against A. solani at 5, 10 and 15 ppm concentrations after 48, 96, 144 and 172 hrs. Corel and reflex at all concentrations produced best growth inhibition of A. solani. The inhibition was maximum by all fungicides at 15 ppm after 172 hrs. All fungicides had a promising inhibitory effect on A. solani, except Solex. It can be concluded from the present investigation that a combination of these strategies can be used in integrated disease management of A. solani on potato.