Fungicidal Efficacy of Leaf Extracts From Khaya senegalensis (Desr.) A. Juss. Irrigated With Agricultural Drainage Water and Treated With Some Fertilizer Types.

This study evaluated the bio-based chemical compounds and antifungal potential of leaf ethanolic extracts from 20-month-old Khaya senegalensis (Desr.) A. Juss. seedlings. Plants were irrigated with three water types: 100% Nile water (NW), 50% NW + 50% agricultural drainage water (ADW), and 100% ADW, and fertilized with NPK, seaweed extract (SE), microbial top strains (TS), or their combinations. The extracts were tested against plant pathogenic fungi, Botrytis fabae and Alternaria alternata. Rutin, gallic acid, and naringenin were the primary bioactive compounds. Under 100% NW, maximum concentrations reached 29.79, 6.87, and 13.039 mg/g extract, respectively. While 100% ADW caused severe abiotic stress and threshold failure in unfertilized plants, adding SE and TS biostimulants to the 50% ADW blend protected the leaf chemical profile (PC1 = 97.5%, PC2 = 1.5%). The highest fungal inhibition percentage (FIP) against B. fabae reached 54.8% using 50% NW + 50% ADW combined with NPK + TS. Against A. alternata, the maximum FIP was 85.6% at 3% with 100% ADW + NPK + TS. Minimum inhibitory concentrations were 0.75%-5% for B. fabae and 0.0625%-0.25% for A. alternata. Thus, K. senegalensis extracts offer a sustainable biopesticide resource for managing plant pathogens under marginal water irrigation.