Assessment of fungicide efficacy against white mold disease (Sclerotinia sclerotiorum) in tomato

White mold caused by Sclerotinia sclerotiorum is a destructive disease of tomato, leading to severe yield losses under protected and field conditions. Given the limited effectiveness of cultural practices alone, the present study aimed to rationally evaluate the efficacy of commonly used fungicides against S. sclerotiorum under laboratory and greenhouse conditions to identify the most effective management options. Seven fungicides were first screened in vitro at four concentrations (25-100 µg ml⁻¹) to assess mycelial growth inhibition over time. Subsequently, the most promising fungicides were evaluated under greenhouse conditions through seed treatment and foliar application to determine their effects on disease incidence, disease severity, and disease control efficacy. In laboratory assays, azoxystrobin, propiconazole, carbendazim, and sulphur completely inhibited mycelial growth at all tested concentrations and observation intervals, whereas difenoconazole and tebuconazole + trifloxystrobin showed high but incomplete inhibition. Iprodione was consistently the least effective fungicide. Greenhouse experiments confirmed significant effects of fungicides, concentrations, and days after inoculation on disease development. Carbendazim emerged as the most effective fungicide in both seed treatment and foliar application, resulting in the lowest disease incidence and severity and the highest disease control efficacy, followed closely by propiconazole. Sulphur showed moderate effectiveness, while azoxystrobin provided comparatively lower and less consistent control under greenhouse conditions. Overall, carbendazim and propiconazole provided consistent, dose-dependent control of tomato white mold through both seed treatment and foliar application, supporting their optimized use in integrated management of S. sclerotiorum.