The invention relates to 3-aryl-4-(2,6-dimethylbenzylidene)isoxazol-5(4H)-ones, to agrochemically active salts thereof, to the use thereof and to methods and compositions for controlling phytopathogenic harmful fungi and insects in and/or on plants or in and/or on seed of plants, to processes for producing such compositions and treated seed, and to the use thereof for controlling phytopathogenic harmful fungi in agriculture, horticulture and forestry, in animal health, in the protection of materials and in the domestic and hygiene sector. The present invention further relates to a process for preparing isoxazolone derivatives.
