Evaluation of in vitro antifungal potential of several fungicides against Alternaria alternata (Fr.) Keissler, the causal agent of potato brown spot in Afghanistan

Potato brown spot caused by Alternaria alternata (Fr.) Keissler is one of the most destructive diseases potato worldwide. The present study was conducted to identify causal agent, and test efficacy several fungicides with different modes actions against A. alternata. Five chemical including; Copper oxychloride (Sufer Oxychloride® 50% WP), Carbendazim (Carbendazim Aria® 60% Penconazole (Penconazole®  20% WE) , Mancozeb (Qadri Mancozeb®  80% WP) Flutriafol 6.94% + Tebuconazole 20.8% (Topgaurd® 30% SC) were tested at four concentrations of; 20, 100, 300 500 mg l, using poisoned food technique. Among fungicides, highest in vitro inhibition (%) mycelial growth pathogen recorded on causing complete (100 %) followed 100 % l; moreover, it strong 90.17 l. Both proved be effective expressing potency 93.75 even lowest concentration 20 l after 5 days fungal incubation, although inhibitory decreased slightly over time 10 incubation. third fungicide (41.91, 75.24 84.21 respectively. least observed (8.77 (21.05 maximum For best our knowledge, this first report as agent Afghanistan.