A first case of Sclerotinia sclerotiorum, also known as white mold, has been identified on watercress (Nasturtium officinale) cultivated in an aquaponic system at the University of Debrecen's Aquaponic Research Station in Hungary. The fungus was identified after affecting 30% of 3-month-old watercress plants, showing symptoms such as withered leaves and stems with white mycelium. Fungal isolates from the infected plants showed similar morphological characteristics, indicating the same fungal strain.