Evaluation of biogenically synthesized magnesium nanoparticles using pumpkin seed and Agaricus bisporus extracts for the management of white rot disease of eggplant caused by Sclerotinia sclerotiorum

Abstract

White rot caused by Sclerotinia sclerotiorum is an important disease that can substantially reduce crop growth and yield. The present study evaluated the antifungal and disease-suppressive potential of biosynthesized magnesium oxide nanoparticles (MgO-NPs) and Agaricus bisporus extracts against S. sclerotiorum and their effects on growth and yield of two cultivars (Jawhara and Barcelona). The most virulent fungal isolate obtained from infected plants was identified molecularly by PCR amplification of the ITS region, which produced an approximately 600-bp amplicon consistent with S. sclerotiorum. In vitro assays showed that MgO-NPs had the strongest antifungal activity, completely inhibiting mycelial growth at 0.70 mL L^-1 and achieving 96% inhibition at 0.50 mL L^-1. The 5% alcoholic mushroom extract inhibited mycelial growth by 60%. SEM characterization revealed predominantly spherical MgO-NPs with particle sizes of approximately 20–50 nm and a mean diameter of about 35 nm. Under greenhouse conditions, the infected control exhibited the highest disease incidence (65.83%) and severity (0.638), whereas the ‘alcoholic extract + MgO-NP’ combined treatment completely suppressed disease incidence and reduced disease severity to 0.052. Treatment applications also substantially improved chlorophyll content, plant height, dry weight, and fruit production. The highest chlorophyll content (46.77 SPAD) was recorded with the’ aqueous extract + MgO-NP’ treatment, while MgO-NPs produced the highest dry weight (20.97 g) and mean fruit weight (2525.5 g plant^-1). Overall, biosynthesized MgO-NPs, particularly when combined with A. bisporus extracts, showed considerable potential for suppressing S. sclerotiorum and improving crop performance.