Evaluation of novel biocontrol strains against white root rot of apple

White root rot (WRR) of apple is a major threat to Kashmir Valley orchards, causing significant economic losses. This study systematically isolated, characterised, and identified the WRR pathogen and evaluated novel biocontrol agents both in vitro and in vivo. The pathogen was identified as Dematophora necatrix through cultural, morphological, and microscopic analyses, and Koch’s postulates. Seven previously isolated BCAs (Skau-Tab-1, Skau-Tab-2, SHO-13, BPR-49, WP-33, WG-4, and BP-26) were tested using dual-culture, volatile metabolite production, mycoparasitism, antibiosis, and pot experiments with one-year-old MM106 apple seedlings. SHO-13 showed the highest inhibition in dual culture (76.85%), antibiosis (82.59%), and volatile metabolite assays (74.07%). BPR-49 was the next most effective. WG-4 and BP-26 were the least effective. All BCAs exhibited positive mycoparasitism. In pot experiments, treatments T6 (SHO-13 + Mancozeb) and T8 (BPR-49 + Carbendazim) recorded the lowest root rot incidence (22.3% and 22.85%), compared to 91.66% in untreated controls, emphasising their value in integrated disease management