The invention relates to 3-aryl-4-(2-thienylmethylene)isoxazol-5(4H)-ones, to agrochemically active salts thereof, to their use 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 preparing such compositions and to treated seed, and to their use for controlling phytopathogenic harmful fungi in agriculture, horticulture and forestry, in animal health, in the protection of materials and in the domestic and hygiene field. The present invention further relates to a process for preparing isoxazolone derivatives.
